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Sample records for infrared complex faraday

  1. Cryogen-free heterodyne-enhanced mid-infrared Faraday rotation spectrometer

    PubMed Central

    Wang, Yin; Nikodem, Michal; Wysocki, Gerard

    2013-01-01

    A new detection method for Faraday rotation spectra of paramagnetic molecular species is presented. Near shot-noise limited performance in the mid-infrared is demonstrated using a heterodyne enhanced Faraday rotation spectroscopy (H-FRS) system without any cryogenic cooling. Theoretical analysis is performed to estimate the ultimate sensitivity to polarization rotation for both heterodyne and conventional FRS. Sensing of nitric oxide (NO) has been performed with an H-FRS system based on thermoelectrically cooled 5.24 μm quantum cascade laser (QCL) and a mercury-cadmium-telluride photodetector. The QCL relative intensity noise that dominates at low frequencies is largely avoided by performing the heterodyne detection in radio frequency range. H-FRS exhibits a total noise level of only 3.7 times the fundamental shot noise. The achieved sensitivity to polarization rotation of 1.8 × 10−8 rad/Hz1/2 is only 5.6 times higher than the ultimate theoretical sensitivity limit estimated for this system. The path- and bandwidth-normalized NO detection limit of 3.1 ppbv-m/Hz1/2 was achieved using the R(17/2) transition of NO at 1906.73 cm−1. PMID:23388967

  2. Enhancement of optical Faraday effect of nonanuclear Tb(III) complexes.

    PubMed

    Nakanishi, Takayuki; Suzuki, Yuki; Doi, Yoshihiro; Seki, Tomohiro; Koizumi, Hitoshi; Fushimi, Koji; Fujita, Koji; Hinatsu, Yukio; Ito, Hajime; Tanaka, Katsuhisa; Hasegawa, Yasuchika

    2014-07-21

    The effective magneto-optical properties of novel nonanuclear Tb(III) complexes with Tb-O lattice (specifically, [Tb9(sal-R)16(μ-OH)10](+)NO3(-), where sal-R = alkyl salicylate (R = -CH3 (Me), -C2H5 (Et), -C3H7 (Pr), or -C4H9 (Bu)) are reported. The geometrical structures of these nonanuclear Tb(III) complexes were characterized using X-ray single-crystal analysis and shape-measure calculation. Optical Faraday rotation was observed in nonanuclear Tb(III) complexes in the visible region. The Verdet constant per Tb(III) ion of the Tb9(sal-Me) complex is 150 times larger than that of general Tb(III) oxide glass. To understand their large Faraday rotation, electron paramagnetic resonance measurements of Gd(III) complexes were carried out. In this Report, the magneto-optical relation to the coordination geometry of Tb ions is discussed.

  3. Suppression of infrared absorption in nanostructured metals by controlling Faraday inductance and electron path length.

    PubMed

    Han, Sang Eon

    2016-02-08

    Nanostructured metals have been intensively studied for optical applications over the past few decades. However, the intrinsic loss of metals has limited the optical performance of the metal nanostructures in diverse applications. In particular, light concentration in metals by surface plasmons or other resonances causes substantial absorption in metals. Here, we avoid plasmonic excitations for low loss and investigate methods to further suppress loss in nanostructured metals. We demonstrate that parasitic absorption in metal nanostructures can be significantly reduced over a broad band by increasing the Faraday inductance and the electron path length. For an example structure, the loss is reduced in comparison to flat films by more than an order of magnitude over most of the very broad spectrum between short and long wavelength infrared. For a photodetector structure, the fraction of absorption in the photoactive material increases by two orders of magnitude and the photoresponsivity increases by 15 times because of the selective suppression of metal absorption. These findings could benefit many metal-based applications that require low loss such as photovoltaics, photoconductive detectors, solar selective surfaces, infrared-transparent defrosting windows, and other metamaterials.

  4. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  5. A potassium Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1992-01-01

    The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.

  6. Michael Faraday's Bicentenary.

    ERIC Educational Resources Information Center

    Williams, L. Pearce; And Others

    1991-01-01

    Six articles discuss the work of Michael Faraday, a chemist whose work revolutionized physics and led directly to both classical field and relativity theory. The scientist as a young man, the electromagnetic experiments of Faraday, his search for the gravelectric effect, his work on optical glass, his laboratory notebooks, and his creative use of…

  7. Broadband Faraday isolator.

    PubMed

    Berent, Michał; Rangelov, Andon A; Vitanov, Nikolay V

    2013-01-01

    Driving on an analogy with the technique of composite pulses in quantum physics, we theoretically propose a broadband Faraday rotator and thus a broadband optical isolator, which is composed of sequences of ordinary Faraday rotators and achromatic quarter-wave plates rotated at the predetermined angles.

  8. Michael Faraday's Bicentenary.

    ERIC Educational Resources Information Center

    Williams, L. Pearce; And Others

    1991-01-01

    Six articles discuss the work of Michael Faraday, a chemist whose work revolutionized physics and led directly to both classical field and relativity theory. The scientist as a young man, the electromagnetic experiments of Faraday, his search for the gravelectric effect, his work on optical glass, his laboratory notebooks, and his creative use of…

  9. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  10. Michael Faraday, media man.

    PubMed

    Fara, Patricia

    2006-03-01

    Michael Faraday was an enthusiastic portrait collector, and he welcomed the invention of photography not only as a possible means of recording observations accurately, but also as a method for advertising science and its practitioners. This article (which is part of the Science in the Industrial Revolution series) shows that like many eminent scientists, Faraday took advantage of the burgeoning Victorian media industry by posing in various roles.

  11. Following Michael Faraday's Footprints

    NASA Astrophysics Data System (ADS)

    Galeano, Javier

    2011-01-01

    Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable for following Michael Faraday's footprints. There are many other places in Europe of special interest for the physics teacher,2,3 and some useful guides to help us visit places as "scientific travelers,"4,5 but this paper focuses on Michael Faraday and London. I have personally visited most of the places described below and found the experience to be really worthwhile.

  12. High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST

    NASA Astrophysics Data System (ADS)

    Ding, W. X.; Lin, L.; Duff, J. R.; Brower, D. L.

    2014-11-01

    Magnetic fluctuation-induced transport driven by global tearing modes has been measured by Faraday-effect polarimetry and interferometry (phase measurements) in the MST reversed field pinch. However, the role of small-scale broadband magnetic and density turbulence in transport remains unknown. In order to investigate broadband magnetic turbulence, we plan to upgrade the existing detector system by using planar-diode fundamental waveguide mixers optimized for high sensitivity. Initial tests indicate these mixers have ×10 sensitivity improvement compared to currently employed corner-cube Schottky-diode mixers and ×5 lower noise. Compact mixer design will allow us to resolve the wavenumbers up to k ˜ 1-2 cm-1 for beam width w = 1.5 cm and 15 cm-1 for beam width w = 2 mm. The system can also be used to measure the scattered signal (amplitude measurement) induced by both plasma density and magnetic fluctuations.

  13. High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST.

    PubMed

    Ding, W X; Lin, L; Duff, J R; Brower, D L

    2014-11-01

    Magnetic fluctuation-induced transport driven by global tearing modes has been measured by Faraday-effect polarimetry and interferometry (phase measurements) in the MST reversed field pinch. However, the role of small-scale broadband magnetic and density turbulence in transport remains unknown. In order to investigate broadband magnetic turbulence, we plan to upgrade the existing detector system by using planar-diode fundamental waveguide mixers optimized for high sensitivity. Initial tests indicate these mixers have ×10 sensitivity improvement compared to currently employed corner-cube Schottky-diode mixers and ×5 lower noise. Compact mixer design will allow us to resolve the wavenumbers up to k ∼ 1-2 cm(-1) for beam width w = 1.5 cm and 15 cm(-1) for beam width w = 2 mm. The system can also be used to measure the scattered signal (amplitude measurement) induced by both plasma density and magnetic fluctuations.

  14. High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST

    SciTech Connect

    Ding, W. X. Lin, L.; Brower, D. L.; Duff, J. R.

    2014-11-15

    Magnetic fluctuation-induced transport driven by global tearing modes has been measured by Faraday-effect polarimetry and interferometry (phase measurements) in the MST reversed field pinch. However, the role of small-scale broadband magnetic and density turbulence in transport remains unknown. In order to investigate broadband magnetic turbulence, we plan to upgrade the existing detector system by using planar-diode fundamental waveguide mixers optimized for high sensitivity. Initial tests indicate these mixers have ×10 sensitivity improvement compared to currently employed corner-cube Schottky-diode mixers and ×5 lower noise. Compact mixer design will allow us to resolve the wavenumbers up to k ∼ 1–2 cm{sup −1} for beam width w = 1.5 cm and 15 cm{sup −1} for beam width w = 2 mm. The system can also be used to measure the scattered signal (amplitude measurement) induced by both plasma density and magnetic fluctuations.

  15. Faraday rotation system. Topical report

    SciTech Connect

    Bauman, L.E.; Wang, W.

    1994-07-01

    The Faraday Rotation System (FRS) is one of the advanced laser-based diagnostics developed at DIAL to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the MHD channel, the system directly measures electron density through a measurement of the induced rotation in the polarization of a far infrared laser beam after passing through the MHD flow along the magnetic field lines. A measurement of the induced polarization ellipticity provides a measure of the electron collision frequency which together with the electron density gives the electron conductivity, a crucial parameter for MHD channel performance. The theory of the measurements, a description of the system, its capabilities, laboratory demonstration measurements on seeded flames with comparison to emission absorption measurements, and the current status of the system are presented in this final report.

  16. Following Michael Faraday's Footprints

    ERIC Educational Resources Information Center

    Galeano, Javier

    2011-01-01

    Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable…

  17. Following Michael Faraday's Footprints

    ERIC Educational Resources Information Center

    Galeano, Javier

    2011-01-01

    Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable…

  18. SMAP Faraday Rotation

    NASA Technical Reports Server (NTRS)

    Le Vine, David

    2016-01-01

    Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

  19. Observation of Trans-Ethanol and Gauche-Ethanol Complexes with Benzene Using Matrix Isolation Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Amicangelo, Jay; Silbaugh, Matthew J.

    2016-06-01

    Ethanol can exist in two conformers, one in which the OH group is trans to the methyl group (trans-ethanol) and the other in which the OH group is gauche to the methyl group (gauche-ethanol). Matrix isolation infrared spectra of ethanol deposited in 20 K argon matrices display distinct infrared peaks that can be assigned to the trans-ethanol and gauche-ethanol conformers, particularly with the O-H stretching vibrations. Given this, matrix isolation experiments were performed in which ethanol (C_2H_5OH) and benzene (C_6H_6) were co-deposited in argon matrices at 20 K in order to determine if conformer specific ethanol complexes with benzene could be observed in the infrared spectra. New infrared peaks that can be attributed to the trans-ethanol and gauche-ethanol complexes with benzene have been observed near the O-H stretching vibrations of ethanol. The initial identification of the new infrared peaks as being due to the ethanol-benzene complexes was established by performing a concentration study (1:200 to 1:1600 S/M ratios), by comparing the co-deposition spectra with the spectra of the individual monomers, by matrix annealing experiments (35 K), and by performing experiments using isotopically labeled ethanol (C_2D_5OD) and benzene (C_6D_6). Quantum chemical calculations were also performed for the C_2H_5OH-C_6H_6 complexes using density functional theory (B3LYP) and ab initio (MP2) methods. Stable minima were found for the both the trans-ethanol and gauche-ethanol complexes with benzene at both levels of theory and were predicted to have similar interaction energies. Both complexes can be characterized as H-π complexes, in which the ethanol is above the benzene ring with the hydroxyl hydrogen interacting with the π cloud of the ring. The theoretical O-H stretching frequencies for the complexes were predicted to be shifted from the monomer frequencies and from each other and these results were used to make the conformer specific infrared peak assignments

  20. Complex structure within Saturn's infrared aurora

    USGS Publications Warehouse

    Stallard, T.; Miller, S.; Lystrup, M.; Achilleos, N.; Bunce, E.J.; Arridge, C.S.; Dougherty, M.K.; Cowley, S.W.H.; Badman, S.V.; Talboys, D.L.; Brown, R.H.; Baines, K.H.; Buratti, B.J.; Clark, R.N.; Sotin, Christophe; Nicholson, P.D.; Drossart, P.

    2008-01-01

    The majority of planetary aurorae are produced by electrical currents flowing between the ionosphere and the magnetosphere which accelerate energetic charged particles that hit the upper atmosphere. At Saturn, these processes collisionally excite hydrogen, causing ultraviolet emission, and ionize the hydrogen, leading to H3+ infrared emission. Although the morphology of these aurorae is affected by changes in the solar wind, the source of the currents which produce them is a matter of debate. Recent models predict only weak emission away from the main auroral oval. Here we report images that show emission both poleward and equatorward of the main oval (separated by a region of low emission). The extensive polar emission is highly variable with time, and disappears when the main oval has a spiral morphology; this suggests that although the polar emission may be associated with minor increases in the dynamic pressure from the solar wind, it is not directly linked to strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained using our current understanding of Saturn's magnetosphere. The equatorward arc of emission exists only on the nightside of the planet, and arises from internal magnetospheric processes that are currently unknown. ??2008 Macmillan Publishers Limited. All rights reserved.

  1. Modified Faraday cup

    DOEpatents

    Elmer, J.W.; Teruya, A.T.; O`Brien, D.W.

    1996-09-10

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams is disclosed. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees from 0{degree} to 360{degree} and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment. 12 figs.

  2. Modified Faraday cup

    DOEpatents

    Elmer, John W.; Teruya, Alan T.; O'Brien, Dennis W.

    1996-01-01

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0.degree. to 360.degree. and the waveforms are recorded by a digitizing storage oscilloscope. Two-din-tensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment.

  3. Michael Faraday vs. the Spiritualists

    NASA Astrophysics Data System (ADS)

    Hirshfeld, Alan

    2006-12-01

    In the 1850s, renowned physicist Michael Faraday launched a public campaign against pseudoscience and spiritualism, which were rampant in England at the time. Faraday objected especially to claims that electrical or magnetic forces were responsible for paranormal phenomena, such as table-spinning and communication with the dead. Using scientific methods, Faraday unmasked the deceptions of spiritualists, clairvoyants and mediums and also laid bare the credulity of a public ill-educated in science. Despite his efforts, Victorian society's fascination with the paranormal swelled. Faraday's debacle anticipates current controversies about public science education and the interface between science and religion. This episode is one of many described in the new biography, The Electric Life of Michael Faraday (Walker & Co.), which chronicles Faraday's discoveries and his unlikely rise from poverty to the pinnacle of the English science establishment.

  4. Faraday instability in deformable domains

    NASA Astrophysics Data System (ADS)

    Pucci, Giuseppe; Ben Amar, Martine; Couder, Yves

    2014-11-01

    We investigate the Faraday instability in floating liquid lenses, as an example of hydrodynamic instability that develops in a domain with flexible boundaries. We show that a mutual adaptation of the instability pattern and the domain shape occurs, as a result of the competition between the wave radiation pressure and the capillary response of the lens border. Two archetypes of behaviour are observed. In the first, stable shapes are obtained experimentally and predicted theoretically as the exact solutions of a Riccati equation, and they result from the equilibrium between wave radiation pressure and capillarity. In the second, the radiation pressure exceeds the capillary response of the lens border and leads to non-equilibrium behaviours, with breaking into smaller domains that have a complex dynamics including spontaneous propagation. The authors are grateful to Université Franco-Italienne (UFI) for financial support.

  5. Infrared spectral identification of complex organic molecules in interstellar grains

    NASA Technical Reports Server (NTRS)

    Greenberg, J. M.; Schutte, W.

    1985-01-01

    The chemical evolution of interstellar grains leads ultimately to a comparison consisting largely of complex organic molecules. Comparison of infrared absorption spectra of laboratory produced analogue materials with astronomical observations confirm the the presence of similar molecules in interstellar space. The abundance of this complex organic matter derived from the strength of the absorption bands is of the order of ten million solar masses and is almost certainly as large or larger than all conceivable planets.

  6. fsclean: Faraday Synthesis CLEAN imager

    NASA Astrophysics Data System (ADS)

    Bell, M. R.; Ensslin, T. A.

    2015-06-01

    Fsclean produces 3D Faraday spectra using the Faraday synthesis method, transforming directly from multi-frequency visibility data to the Faraday depth-sky plane space. Deconvolution is accomplished using the CLEAN algorithm, and the package includes Clark and Högbom style CLEAN algorithms. Fsclean reads in MeasurementSet visibility data and produces HDF5 formatted images; it handles images and data of arbitrary size, using scratch HDF5 files as buffers for data that is not being immediately processed, and is limited only by available disk space.

  7. Hysteretic Faraday waves

    NASA Astrophysics Data System (ADS)

    Périnet, Nicolas; Falcón, Claudio; Chergui, Jalel; Shin, Seungwon; Juric, Damir

    2016-11-01

    We study with numerical simulations the two-dimensional Faraday waves in two immiscible incompressible fluids when the lower fluid layer is shallow. After the appearance of the well known subharmonic stationary waves, a further instability is observed while the control parameter passes a secondary threshold. A new state then arises, composed of stationary waves with about twice the original pattern amplitude. The bifurcation presents hysteresis: there exists a finite range of the control parameter in which both states are stable. By means of a simple stress balance, we show that a change of the shear stress can explain this hysteresis. Our predictions based on this model are in agreement with our numerical results. Project funded by FONDECYT Grants 1130354, 3140522 and the National Research Foundation of Korea (NRF- 2014R1A2A1A11051346). Computations supported by the supercomputing infrastructures of the NLHPC (ECM-02) and GENCI (IDRIS).

  8. Fabry-Perot enhanced Faraday rotation in graphene.

    PubMed

    Ubrig, Nicolas; Crassee, Iris; Levallois, Julien; Nedoliuk, Ievgeniia O; Fromm, Felix; Kaiser, Michl; Seyller, Thomas; Kuzmenko, Alexey B

    2013-10-21

    We demonstrate that giant Faraday rotation in graphene in the terahertz range due to the cyclotron resonance is further increased by constructive Fabry-Perot interference in the supporting substrate. Simultaneously, an enhanced total transmission is achieved, making this effect doubly advantageous for graphene-based magneto-optical applications. As an example, we present far-infrared spectra of epitaxial multilayer graphene grown on the C-face of 6H-SiC, where the interference fringes are spectrally resolved and a Faraday rotation up to 0.15 radians (9°) is attained. Further, we discuss and compare other ways to increase the Faraday rotation using the principle of an optical cavity.

  9. Fabry-Perot enhanced Faraday rotation in graphene

    NASA Astrophysics Data System (ADS)

    Ubrig, Nicolas; Crassee, Iris; Levallois, Julien; Nedoliuk, Ievgeniia O.; Fromm, Felix; Kaiser, Michl; Seyller, Thomas; Kuzmenko, Alexey B.

    2013-10-01

    We demonstrate that giant Faraday rotation in graphene in the terahertz range due to the cyclotron resonance is further increased by constructive Fabry-Perot interference in the supporting substrate. Simultaneously, an enhanced total transmission is achieved, making this effect doubly advantageous for graphene-based magneto-optical applications. As an example, we present far-infrared spectra of epitaxial multilayer graphene grown on the C-face of 6H-SiC, where the interference fringes are spectrally resolved and a Faraday rotation up to 0.15 radians (9{\\deg}) is attained. Further, we discuss and compare other ways to increase the Faraday rotation using the principle of an optical cavity.

  10. Faraday anomalous dispersion optical tuners

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.

  11. Faraday imaging at high temperatures

    DOEpatents

    Hackel, L.A.; Reichert, P.

    1997-03-18

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs.

  12. Faraday imaging at high temperatures

    DOEpatents

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  13. Faraday anomalous dispersion optical tuners

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.

  14. MUSIC for Faraday rotation measure synthesis

    NASA Astrophysics Data System (ADS)

    Andrecut, M.

    2013-03-01

    Faraday rotation measure (RM) synthesis requires the recovery of the Faraday dispersion function (FDF) from measurements restricted to limited wavelength ranges, which is an ill-conditioned deconvolution problem. Here, we propose a novel deconvolution method based on an extension of the MUltiple SIgnal Classification (MUSIC) algorithm. The complexity and speed of the method is determined by the eigen-decomposition of the covariance matrix of the observed polarizations. We show numerically that for high to moderate signal-to-noise ratio (S/N) cases the RM-MUSIC method is able to recover the Faraday depth values of closely spaced pairs of thin RM components, even in situations where the peak response of the FDF is outside of the RM range between the two input RM components. This result is particularly important because the standard deconvolution approach based on RM-CLEAN fails systematically in such situations, due to its greedy mechanism used to extract the RM components. For low S/N situations, both the RM-MUSIC and RM-CLEAN methods provide similar results.

  15. Infrared spectroscopy of V2+(H2O) complexes

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, B.; Duncan, M. A.

    2012-03-01

    Doubly charged vanadium-water complexes are produced by laser vaporization in a pulsed supersonic expansion. Size-selected ions are studied with infrared photodissociation spectroscopy in the O-H stretch region using argon complex predissociation. Density functional theory calculations provide structures and vibrational spectra of these ions. The O-H stretches of V2+(H2O) appear at lower frequencies than those of the free water molecule or V+(H2O). The symmetric stretch is more intense than the asymmetric stretch in both V+(H2O) and V2+(H2O) complexes. Spectra of V2+(H2O)Arn (n = 2-7) show that the coordination of the V2+ is filled with six ligands, i.e. one water and five argon atoms.

  16. Communication: Infrared spectroscopy of salt-water complexes

    NASA Astrophysics Data System (ADS)

    Tandy, Jon; Feng, Cheng; Boatwright, Adrian; Sarma, Gautam; Sadoon, Ahmed M.; Shirley, Andrew; Das Neves Rodrigues, Natercia; Cunningham, Ethan M.; Yang, Shengfu; Ellis, Andrew M.

    2016-03-01

    To explore how the ion-pair in a single salt molecule evolves with the addition of water, infrared (IR) spectra of complexes composed of NaCl and multiple water molecules have been recorded for the first time. The NaCl(H2O)n complexes were formed and probed in liquid helium nanodroplets, and IR spectra were recorded for n = 1 → 4. The spectra for n = 1, 2, and 3 are consistent with formation of the lowest energy contact-ion pair structures in which each water molecule forms a single ionic hydrogen bond to an intact Na+Cl- ion-pair. Alternative structures with hydrogen bonding between water molecules become energetically competitive for n = 4, and the IR spectrum indicates likely the coexistence of at least two isomers.

  17. Active Faraday optical frequency standard.

    PubMed

    Zhuang, Wei; Chen, Jingbiao

    2014-11-01

    We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

  18. Infrared spectroscopy of nonclassical ions and their complexes

    SciTech Connect

    Boo, Doo Wan

    1995-01-01

    This thesis describes an infrared spectroscopic study on the structures and dynamics of the nonclassical ions and their complexes, using ion trap vibrational predissociation spectroscopy. Chapter One provides an introduction to the experimental apparatus used in this work. Chapter Two describes the previous theoretical and experimental works on the carbonium ion CH5+ and infrared spectroscopic and theoretical works on CH5+. CH5+ was predicted to scramble constantly without possessing a stable structure. In Chapter Three, the infrared spectroscopy for the molecular hydrogen solvated carbonium ions CH5+(H2)n (n=1-6) in the frequency region of 2700-4200 cm-1 are presented and compared with the results of ab initio molecular dynamics simulation on CH5+(H2)n (n=0-3). The results suggested that the scrambling of CH5+ slowed down considerably by the stabilization effects of the solvent H2 molecules, and it was completely frozen out when the first three H2 molecules were bound to the core CH5+. Chapter Four presents the complete infrared spectra for the solvated carbonium ions, CH5+(A)x(B)y (A,B=H2, Ar, N2, CH4;x,y=0-5) in the frequency region of 2500-3200 cm-1. As the binding affinities of the solvent molecules and the number of the solvent molecules in the clusters increased, the scrambling of CH5+ slowed down substantially. The structures of the solvated carbonium ions and the evidence for rapid proton transfer in CH5+(CH4) were also presented. Chapter Five presents the vib-rotational spectrum for the H-H stretching mode of the silanium ion SiH5+. The results suggested that Si

  19. Ultrafast infrared studies of complex ligand rearrangements in solution

    SciTech Connect

    Payne, Christine K.

    2003-01-01

    The complete description of a chemical reaction in solution depends upon an understanding of the reactive molecule as well as its interactions with the surrounding solvent molecules. Using ultrafast infrared spectroscopy it is possible to observe both the solute-solvent interactions and the rearrangement steps which determine the overall course of a chemical reaction. The topics addressed in these studies focus on reaction mechanisms which require the rearrangement of complex ligands and the spectroscopic techniques necessary for the determination of these mechanisms. Ligand rearrangement is studied by considering two different reaction mechanisms for which the rearrangement of a complex ligand constitutes the most important step of the reaction. The first system concerns the rearrangement of a cyclopentadienyl ring as the response of an organometallic complex to a loss of electron density. This mechanism, commonly referred to as ''ring slip'', is frequently cited to explain reaction mechanisms. However, the ring slipped intermediate is too short-lived to be observed using conventional methods. Using a combination of ultrafast infrared spectroscopy and electronic structure calculations it has been shown that the intermediate exists, but does not form an eighteen-electron intermediate as suggested by traditional molecular orbital models. The second example examines the initial steps of alkyne polymerization. Group 6 (Cr, Mo, W) pentacarbonyl species are generated photolytically and used to catalyze the polymerization of unsaturated hydrocarbons through a series of coordination and rearrangement steps. Observing this reaction on the femto- to millisecond timescale indicates that the initial coordination of an alkyne solvent molecule to the metal center results in a stable intermediate that does not rearrange to form the polymer precursor. This suggests that polymerization requires the dissociation of additional carbonyl ligands before rearrangement can occur. Overall

  20. Infrared Spectroscopy of Charge Transfer Complexes of Purines and Pyrimidines

    SciTech Connect

    Rathod, Pravinsinh I.; Oza, A. T.

    2011-10-20

    The FTIR spectra of charge transfer complexes of purines and pyrimidines with organic acceptors such as TCNQ, TCNE, DDQ, chloranil and iodine are obtained and studied in the present work. Adenine, guanine, thymine, cytosine and uracil are the purines and pyrimidines which are found as constituent of DNA and RNA. Charge transfer induced hydrogen bonding is concluded on the basis of indirect transitions observed in the infrared range in these CTCs. Some CTCs show gaussian bands revealing delocalization of charge carriers. The CTCs show interband transition in three-dimensions rather than two-dimensions unlike CTCs of amino acids. There is no extended hydrogen bonded network spanning the whole crystal. This leads to indirect transition due to locally deformed lattice furnishing a phonon-assisted transition.

  1. Near infrared photodissociation spectra of the aniline +-argon ionic complexes

    NASA Astrophysics Data System (ADS)

    Pino, T.; Douin, S.; Boudin, N.; Bréchignac, Ph.

    2006-02-01

    The near infrared spectra of the ionic complexes aniline(NH 2) +-argon and aniline(ND 2) +-argon have been measured by laser photodissociation spectroscopy. The bands observed from 10 500 to 13 500 cm -1 have been assigned to the D1(A˜2A2)←D0(X˜2B1) electronic transition within the solvated chromophore. They are characterized by a long vibrational progression involving the 6a mode. On the basis of CASSCF calculations, a large change of geometry along this coordinate is found while the amino group remains in the ring plane. Therefore, a change of the conjugation of the ring rather than a charge transfer is inferred. This is thought to be the origin of the extent of the progression.

  2. Infrared Spectroscopy of Charge Transfer Complexes of Purines and Pyrimidines

    NASA Astrophysics Data System (ADS)

    Rathod, Pravinsinh I.; Oza, A. T.

    2011-10-01

    The FTIR spectra of charge transfer complexes of purines and pyrimidines with organic acceptors such as TCNQ, TCNE, DDQ, chloranil and iodine are obtained and studied in the present work. Adenine, guanine, thymine, cytosine and uracil are the purines and pyrimidines which are found as constituent of DNA and RNA. Charge transfer induced hydrogen bonding is concluded on the basis of indirect transitions observed in the infrared range in these CTCs. Some CTCs show gaussian bands revealing delocalization of charge carriers. The CTCs show interband transition in three-dimensions rather than two-dimensions unlike CTCs of amino acids. There is no extended hydrogen bonded network spanning the whole crystal. This leads to indirect transition due to locally deformed lattice furnishing a phonon-assisted transition.

  3. Building a better Faraday cage

    NASA Astrophysics Data System (ADS)

    MartinAlfven; Wright, David; skocpol; Rounce, Graham; Richfield, Jon; W, Nick; wheelsonfire

    2015-11-01

    In reply to the physicsworld.com news article “Are Faraday cages less effective than previously thought?” (15 September, http://ow.ly/SfklO), about a study that indicated, based on mathematical modelling, that conducting wire-mesh cages may not be as good at excluding electromagnetic radiation as is commonly assumed.

  4. Faraday's Law and Seawater Motion

    ERIC Educational Resources Information Center

    De Luca, R.

    2010-01-01

    Using Faraday's law, one can illustrate how an electromotive force generator, directly utilizing seawater motion, works. The conceptual device proposed is rather simple in its components and can be built in any high school or college laboratory. The description of the way in which the device generates an electromotive force can be instructive not…

  5. Faraday's first dynamo: A retrospective

    NASA Astrophysics Data System (ADS)

    Smith, Glenn S.

    2013-12-01

    In the early 1830s, Michael Faraday performed his seminal experimental research on electromagnetic induction, in which he created the first electric dynamo—a machine for continuously converting rotational mechanical energy into electrical energy. His machine was a conducting disc, rotating between the poles of a permanent magnet, with the voltage/current obtained from brushes contacting the disc. In his first dynamo, the magnetic field was asymmetric with respect to the axis of the disc. This is to be contrasted with some of his later symmetric designs, which are the ones almost invariably discussed in textbooks on electromagnetism. In this paper, a theoretical analysis is developed for Faraday's first dynamo. From this analysis, the eddy currents in the disc and the open-circuit voltage for arbitrary positioning of the brushes are determined. The approximate analysis is verified by comparing theoretical results with measurements made on an experimental recreation of the dynamo. Quantitative results from the analysis are used to elucidate Faraday's qualitative observations, from which he learned so much about electromagnetic induction. For the asymmetric design, the eddy currents in the disc dissipate energy that makes the dynamo inefficient, prohibiting its use as a practical generator of electric power. Faraday's experiments with his first dynamo provided valuable insight into electromagnetic induction, and this insight was quickly used by others to design practical generators.

  6. A Mobile Phone Faraday Cage

    ERIC Educational Resources Information Center

    French, M. M. J.

    2011-01-01

    A Faraday cage is an interesting physical phenomenon where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block the signal to a mobile phone by enclosing it in a metal can. The background of the physics behind this is…

  7. Faraday Cage Protects Against Lightning

    NASA Technical Reports Server (NTRS)

    Jafferis, W.; Hasbrouck, R. T.; Johnson, J. P.

    1992-01-01

    Faraday cage protects electronic and electronically actuated equipment from lightning. Follows standard lightning-protection principles. Whether lightning strikes cage or cables running to equipment, current canceled or minimized in equipment and discharged into ground. Applicable to protection of scientific instruments, computers, radio transmitters and receivers, and power-switching equipment.

  8. A Mobile Phone Faraday Cage

    ERIC Educational Resources Information Center

    French, M. M. J.

    2011-01-01

    A Faraday cage is an interesting physical phenomenon where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block the signal to a mobile phone by enclosing it in a metal can. The background of the physics behind this is…

  9. Various Paths to Faraday's Law

    ERIC Educational Resources Information Center

    Redzic, Dragan V.

    2008-01-01

    In a recent note, the author presented a derivation of Faraday's law of electromagnetic induction for a closed filamentary circuit C(t) which is moving at relativistic velocities and also changing its shape as it moves via the magnetic vector potential. Recently, Kholmetskii et al, while correcting an error in an equation, showed that it can be…

  10. Various Paths to Faraday's Law

    ERIC Educational Resources Information Center

    Redzic, Dragan V.

    2008-01-01

    In a recent note, the author presented a derivation of Faraday's law of electromagnetic induction for a closed filamentary circuit C(t) which is moving at relativistic velocities and also changing its shape as it moves via the magnetic vector potential. Recently, Kholmetskii et al, while correcting an error in an equation, showed that it can be…

  11. Faraday's Law and Seawater Motion

    ERIC Educational Resources Information Center

    De Luca, R.

    2010-01-01

    Using Faraday's law, one can illustrate how an electromotive force generator, directly utilizing seawater motion, works. The conceptual device proposed is rather simple in its components and can be built in any high school or college laboratory. The description of the way in which the device generates an electromotive force can be instructive not…

  12. BROADBAND RADIO POLARIMETRY AND FARADAY ROTATION OF 563 EXTRAGALACTIC RADIO SOURCES

    SciTech Connect

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-12-10

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1′ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  13. Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources

    NASA Astrophysics Data System (ADS)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-12-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1‧ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  14. Faraday rotation measure synthesis of UGC 10288

    NASA Astrophysics Data System (ADS)

    Kamieneski, Patrick; Wang, Q. Daniel; Pare, Dylan; Sullivan, Kendall

    2017-01-01

    Faraday rotation measure synthesis is a powerful tool that has been employed in the past decade when studying line-of-sight magnetic fields of galactic and extragalactic sources. Rotation measures, which are sensitive to the strength and direction of fields in an intervening medium between the source and observer, were classically determined by assuming a single, uniform Faraday-rotating medium. Rotation measure synthesis, on the other hand, is a more robust method that allows for probing a more complicated scenario. We will outline results from a study of magnetic field structure in the disk and halo of edge-on galaxy UGC 10288, using 6 cm and 20 cm observations from CHANG-ES (Continuum Halos in Nearby Galaxies - an EVLA Survey). The presence of a strongly polarized complex background source situated perpendicular to the foreground disk allows for an investigation of the disk-halo magnetic fields of UGC 10288. In particular, we present evidence of magnetic field reversals above the plane of the disk. This finding is not easily explained solely by the prevailing α-Ω dynamo mechanism. Rather, a field reversal may be indicative of different parities of the poloidal field components for the individual disk and halo mechanisms.

  15. Faraday rotation in CMB maps

    NASA Astrophysics Data System (ADS)

    Ruiz-Granados, Beatriz; Battaner, Eduardo; Florido, Estrella

    2016-10-01

    WMAP CMB polarization maps have been used to detect a low signal of Faraday Rotation (FR). If this detection is not interpreted as simple noise, it could be produced: at the last scattering surface (LSS) (z=1100), being primordial, at Reionization (z=10), in the Milky Way. The second interpretation is favoured here. In this case magnetic fields at Reionization with peak values of the order of 10-8 G should produce this observational FR.

  16. Faraday Dispersion Functions of Galaxies

    NASA Astrophysics Data System (ADS)

    Ideguchi, Shinsuke; Tashiro, Yuichi; Akahori, Takuya; Takahashi, Keitaro; Ryu, Dongsu

    2014-09-01

    The Faraday dispersion function (FDF), which can be derived from an observed polarization spectrum by Faraday rotation measure synthesis, is a profile of polarized emissions as a function of Faraday depth. We study intrinsic FDFs along sight lines through face-on Milky Way like galaxies by means of a sophisticated galactic model incorporating three-dimensional MHD turbulence, and investigate how much information the FDF intrinsically contains. Since the FDF reflects distributions of thermal and cosmic-ray electrons as well as magnetic fields, it has been expected that the FDF could be a new probe to examine internal structures of galaxies. We, however, find that an intrinsic FDF along a sight line through a galaxy is very complicated, depending significantly on actual configurations of turbulence. We perform 800 realizations of turbulence and find no universal shape of the FDF even if we fix the global parameters of the model. We calculate the probability distribution functions of the standard deviation, skewness, and kurtosis of FDFs and compare them for models with different global parameters. Our models predict that the presence of vertical magnetic fields and the large-scale height of cosmic-ray electrons tend to make the standard deviation relatively large. In contrast, the differences in skewness and kurtosis are relatively less significant.

  17. Deconvolving Current from Faraday Rotation Measurement

    SciTech Connect

    Stephen E. Mitchell

    2008-02-01

    In this paper, a unique software program is reported which automatically decodes the Faraday rotation signal into a time-dependent current representation. System parameters, such as the Faraday fiber’s Verdet constant and number of loops in the sensor, are the only user-interface inputs. The central aspect of the algorithm utilizes a short-time Fourier transform, which reveals much of the Faraday rotation measurement’s implicit information necessary for unfolding the dynamic current measurement.

  18. Quantum Faraday Effect in the Universe

    NASA Astrophysics Data System (ADS)

    Rodríguez, Lídice Cruz; Martínez, Aurora Pérez; Piccinelli, Gabriella; Querts, Elizabeth Rodríguez

    We study the Quantum Faraday rotation starting from the photon self-energy in the presence of a constant magnetic field. The Faraday angle is calculated in the non-degenerate regime and for weak field limit. Two physical scenarios, possibly characterized by these conditions, are the recombination epoch and the jets originated in pulsars. We discuss the resonant behavior that the Faraday angle exhibits in these scenarios and investigate the possibility of detecting cosmic magnetic fields through this resonant mechanism.

  19. Extreme events in Faraday waves

    NASA Astrophysics Data System (ADS)

    Punzmann, Horst; Shats, Michael; Xia, Hua

    2014-05-01

    Observations of extreme wave events in the ocean are rare due to their low statistical probability. In the laboratory however, the evolution of extreme wave events can be studied in great detail with high spatial and temporal resolution. The reported surface wave experiments in the short wavelength gravity-capillary range aim to contribute to the understanding of some of the underlying mechanisms for rogue wave generation. In this talk, we report on extreme wave events in parametrically excited Faraday waves. Faraday waves appear if a fluid is accelerated (normal to the fluid surface) above a critical threshold. A variety of novel tools have been deployed to characterize the 2D surface elevation. The results presented show spatio-temporal and statistical data on the surface wave conditions leading up to extreme wave events. The peak in wave amplitude during such an event is shown to exceed six times the standard deviation of the average wave field with significantly increased statistical probability compared to the background wave field [1]. The experiments also show that parametrically excited waves can be viewed as assembles of oscillons [2] (or oscillating solitons) where modulation instability seems to play a crucial role in their formation. More detailed studies on the oscillon dynamics reveal that the onset of an increased probability of extreme wave events correlates with the increase in the oscillons mobility and merger [3]. Reference: 1. Xia H., Maimbourg T., Punzmann H., and Shats M., Oscillon dynamics and rogue wave generation in Faraday surface ripples, Physical Review Letters 109, 114502 (2012) 2. Shats M., Xia H., and Punzmann H., Parametrically excited water surface ripples as ensembles of oscillons, Physical Review Letters 108, 034502 (2012) 3. Shats M., Punzmann H., Xia H., Capillary rogue waves, Physical Review Letters, 104, 104503 (2010)

  20. Faraday screen sputtering on TPX

    SciTech Connect

    Ehst, D.A.

    1994-12-01

    The TPX design stipulates that the ion-cyclotron resonance frequency (ICRF) antenna must have a Faraday screen (FS). The author considers here possible low Z coatings for the screen, as well as sputtering behavior of the Ni and Ti substrates. The theory of rf-induced sputtering has been developed, and he follows those theoretical approaches. The author`s emphasis will be on both impurity generation as a possible source of increased Z{sub eff}, and also on actual erosion-lifetime of the materials under worst case conditions.

  1. Faraday screen sputtering on TPX

    NASA Astrophysics Data System (ADS)

    Ehst, D. A.

    1994-12-01

    The TPX design stipulates that the ion-cyclotron resonance frequency (ICRF) antenna must have a Faraday screen (FS). The author considers here possible low Z coatings for the screen, as well as sputtering behavior of the Ni and Ti substrates. The theory of RF-induced sputtering has been developed, and follows those theoretical approaches. The author's emphasis will be on both impurity generation as a possible source of increased Z(sub eff), and also on actual erosion-lifetime of the materials under worst case conditions.

  2. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.

    1992-01-01

    The present calculations of the performance of Faraday anomalous dispersion optical filters (FADOF) on IR transitions indicate that such filters may furnish high transmission, narrow-pass bandwidth, and low equivalent noise bandwidth under optimum operating conditions. A FADOF consists of an atomic vapor cell between crossed polarizers that are subject to a dc magnetic field along the optical path; when linearly polarized light travels along the direction of the magnetic field through the dispersive atomic vapor, a polarization rotation occurs. If FADOF conditions are suitably adjusted, a maximum transmission with very narrow bandwidth is obtained.

  3. Faraday and the Philosophical Magazine

    NASA Astrophysics Data System (ADS)

    Weinberger, P.

    2013-05-01

    Faraday is considered to be one of the greatest scientists of all time. He not only was a meticulous experimentalist, a true experimental wizard, but also a very prolific author. The many important contributions (almost 50) that he published in the Philosophical Magazine make it highly desirable to catalogue his various inventions, 'discoveries' in his own words, in a scientific language so characteristic of the nineteenth century. It is the purpose of this commentary to guide the reader through his achievements in electrochemistry, magnetism, electric and electromagnetic induction, even 'industrial' applications; to enable him to address a present day audience by means of his contributions to the Philosophical Magazine.

  4. Near infrared spectroscopy and chemometrics analysis of complex traits in animal physiology

    USDA-ARS?s Scientific Manuscript database

    Near infrared reflectance (NIR) applications have been expanding from the traditional framework of small molecule chemical purity and composition (as defined by spectral libraries) to complex system analysis and holistic exploratory approaches to questions in biochemistry, biophysics and environment...

  5. Soliton mode locking by nonlinear Faraday rotation

    SciTech Connect

    Wabnitz, S.; Westin, E.; Frey, R.; Flytzanis, C.

    1996-11-01

    We propose nonlinear Faraday rotation as a mechanism for achieving stable polarization mode locking of a soliton laser. We analyze by perturbation theory and beam-propagation simulations the interplay between bandwidth-limited gain, gain dichroism, and linear and nonlinear Faraday rotation. {copyright} {ital 1996 Optical Society of America.}

  6. Michael Faraday's work on optical glass

    NASA Astrophysics Data System (ADS)

    James, Frank A. J. L.

    1991-09-01

    This article discusses Faraday's work of the late 1820s to improve optical glass for the joint Royal Society/Board of Longitude Committee set up for this purpose. It points out the importance of this work for some of Faraday's later physical researches.

  7. Active imaging system with Faraday filter

    DOEpatents

    Snyder, James J.

    1993-01-01

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  8. Active imaging system with Faraday filter

    DOEpatents

    Snyder, J.J.

    1993-04-13

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  9. Lines of Force: Faraday's and Students' Views.

    ERIC Educational Resources Information Center

    Pocovi, M. Cecilia; Finley, Fred

    2002-01-01

    Analyzes how electric and magnetic lines of force were conceived by Faraday and how they are understood by a group of Argentine university students after receiving instruction. Results show that many students possess ideas similar to those of Faraday in that lines of force are conceived as real physical entities responsible for the transmission of…

  10. Faraday current sensor with temperature monitoring

    NASA Astrophysics Data System (ADS)

    Perciante, César D.; Ferrari, José A.

    2005-11-01

    We present a novel optical current sensor based on the Faraday effect that incorporates a temperature monitoring system. The monitoring element is a temperature-dependent birefringent plate placed at the Faraday sensor head. Measurement of the plate retardation permits compensation for the temperature dependence of the Verdet constant. Validation experiments are presented and discussed.

  11. WW domain folding complexity revealed by infrared spectroscopy.

    PubMed

    Davis, Caitlin M; Dyer, R Brian

    2014-09-02

    Although the intrinsic tryptophan fluorescence of proteins offers a convenient probe of protein folding, interpretation of the fluorescence spectrum is often difficult because it is sensitive to both global and local changes. Infrared (IR) spectroscopy offers a complementary measure of structural changes involved in protein folding, because it probes changes in the secondary structure of the protein backbone. Here we demonstrate the advantages of using multiple probes, infrared and fluorescence spectroscopy, to study the folding of the FBP28 WW domain. Laser-induced temperature jumps coupled with fluorescence or infrared spectroscopy have been used to probe changes in the peptide backbone on the submillisecond time scale. The relaxation dynamics of the β-sheets and β-turn were measured independently by probing the corresponding IR bands assigned in the amide I region. Using these wavelength-dependent measurements, we observe three kinetics phases, with the fastest process corresponding to the relaxation kinetics of the turns. In contrast, fluorescence measurements of the wild-type WW domain and tryptophan mutants exhibit single-exponential kinetics with a lifetime that corresponds to the slowest phase observed by infrared spectroscopy. Mutant sequences provide evidence of an intermediate dry molten globule state. The slowest step in the folding of this WW domain is the tight packing of the side chains in the transition from the dry molten globule intermediate to the native structure. This study demonstrates that using multiple complementary probes enhances the interpretation of protein folding dynamics.

  12. WW Domain Folding Complexity Revealed by Infrared Spectroscopy

    PubMed Central

    2015-01-01

    Although the intrinsic tryptophan fluorescence of proteins offers a convenient probe of protein folding, interpretation of the fluorescence spectrum is often difficult because it is sensitive to both global and local changes. Infrared (IR) spectroscopy offers a complementary measure of structural changes involved in protein folding, because it probes changes in the secondary structure of the protein backbone. Here we demonstrate the advantages of using multiple probes, infrared and fluorescence spectroscopy, to study the folding of the FBP28 WW domain. Laser-induced temperature jumps coupled with fluorescence or infrared spectroscopy have been used to probe changes in the peptide backbone on the submillisecond time scale. The relaxation dynamics of the β-sheets and β-turn were measured independently by probing the corresponding IR bands assigned in the amide I region. Using these wavelength-dependent measurements, we observe three kinetics phases, with the fastest process corresponding to the relaxation kinetics of the turns. In contrast, fluorescence measurements of the wild-type WW domain and tryptophan mutants exhibit single-exponential kinetics with a lifetime that corresponds to the slowest phase observed by infrared spectroscopy. Mutant sequences provide evidence of an intermediate dry molten globule state. The slowest step in the folding of this WW domain is the tight packing of the side chains in the transition from the dry molten globule intermediate to the native structure. This study demonstrates that using multiple complementary probes enhances the interpretation of protein folding dynamics. PMID:25121968

  13. Faraday diagnostics for ALT-3

    SciTech Connect

    Oro, David M; Tabaka, Leonard J

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the ALT-3 experiment.

  14. Faraday wave lattice as an elastic metamaterial.

    PubMed

    Domino, L; Tarpin, M; Patinet, S; Eddi, A

    2016-05-01

    Metamaterials enable the emergence of novel physical properties due to the existence of an underlying subwavelength structure. Here, we use the Faraday instability to shape the fluid-air interface with a regular pattern. This pattern undergoes an oscillating secondary instability and exhibits spontaneous vibrations that are analogous to transverse elastic waves. By locally forcing these waves, we fully characterize their dispersion relation and show that a Faraday pattern presents an effective shear elasticity. We propose a physical mechanism combining surface tension with the Faraday structured interface that quantitatively predicts the elastic wave phase speed, revealing that the liquid interface behaves as an elastic metamaterial.

  15. Isotopic labelling studies on far-infrared spectra of nickel-histamine complexes

    NASA Astrophysics Data System (ADS)

    Drożdżewski, Piotr; Kordon, Ewa

    2000-11-01

    Nickel-histamine (hm) complexes type [Ni(hm)Cl 2] and [Ni(hm) 3] X2 (Where X=Cl, Br, I, ClO 4) were investigated in the far-infrared region. Metal isotope labelling and deuteration effects were employed for observed band assignments. Metal-ligand vibrations were discussed and correlated with the structures of the complexes.

  16. Conformation of DNA in chromatin protein-DNA complexes studied by infrared spectroscopy.

    PubMed Central

    Liquier, J; Gadenne, M C; Taillandier, E; Defer, N; Favatier, F; Kruh, J

    1979-01-01

    The following observations concerning the DNA secondary structures in various nucleohistone complexes were made by infrared spectroscopy: 1/ in chromatin, chromatin extracted by 0.6 M NaCl, nucleosomes, and histone-DNA reconstituted complexes, the DNA remains in a B type conformation at low relative hygrometry; 2/ in chromatin extracted by tRNA and in non histone protein-DNA reconstituted complexes, the DNA can adopt an A type conformation. Infrared linear dichroism data show that in NHP-DNA complexes the low relative hygrometry conformation of DNA may be modified and that the infrared parameter -1090 is close to that measured for RNA's or DNA-RNA hybrids. It is concluded that the histones block the DNA in a B form and that some of the NHP could be involved in the control of the secondary structure of DNA in chromatin. Images PMID:450704

  17. Giant Faraday Rotation of High-Order Plasmonic Modes in Graphene-Covered Nanowires.

    PubMed

    Kuzmin, Dmitry A; Bychkov, Igor V; Shavrov, Vladimir G; Temnov, Vasily V

    2016-07-13

    Plasmonic Faraday rotation in nanowires manifests itself in the rotation of the spatial intensity distribution of high-order surface plasmon polariton (SPP) modes around the nanowire axis. Here we predict theoretically the giant Faraday rotation for SPPs propagating on graphene-coated magneto-optically active nanowires. Upon the reversal of the external magnetic field pointing along the nanowire axis some high-order plasmonic modes may be rotated by up to ∼100° on the length scale of about 500 nm at mid-infrared frequencies. Tuning the carrier concentration in graphene by chemical doping or gate voltage allows for controlling SPP-properties and notably the rotation angle of high-order azimuthal modes. Our results open the door to novel plasmonic applications ranging from nanowire-based Faraday isolators to the magnetic control in quantum-optical applications.

  18. Calibrated Faraday current and magnetic field sensor

    NASA Astrophysics Data System (ADS)

    Neyer, B. T.; Chang, J.; Lockwood, G. J.; Ruggles, L. E.

    A calibrated optical fiber Faraday rotation current sensor is developed. This sensor has a gigahertz response, is immune to electromagnetic interference, and is constructed entirely of dielectric material. All of these advantages make the sensor ideal for pulsed power measurements.

  19. Michael Faraday's Contributions to Archaeological Chemistry.

    PubMed

    Moshenska, Gabriel

    2015-08-01

    The analysis of ancient artefacts is a long but largely neglected thread within the histories of archaeology and chemistry. This paper examines Michael Faraday's contributions to this nascent field, drawing on his published correspondence and the works of his antiquarian collaborators, and focusing in particular on his analyses of Romano-British and ancient Egyptian artefacts. Faraday examined the materials used in ancient Egyptian mummification, and provided the first proof of the use of lead glazes on Roman ceramics. Beginning with an assessment of Faraday's personal interests and early work on antiquities with Humphry Davy, this paper critically examines the historiography of archaeological chemistry and attempts to place Faraday's work within its institutional, intellectual, and economic contexts.

  20. Faraday Rotation Measurement with the SMAP Radiometer

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.; Abraham, S.

    2016-01-01

    Faraday rotation is an issue that needs to be taken into account in remote sensing of parameters such as soil moisture and ocean salinity at L-band. This is especially important for SMAP because Faraday rotation varies with azimuth around the conical scan. SMAP retrieves Faraday rotation in situ using the ratio of the third and second Stokes parameters, a procedure that was demonstrated successfully by Aquarius. This manuscript reports the performance of this algorithm on SMAP. Over ocean the process works reasonably well and results compare favorably with expected values. But over land, the inhomogeneous nature of the scene results in much noisier, and in some cases unreliable estimates of Faraday rotation.

  1. Wave-particle interaction in the Faraday waves.

    PubMed

    Francois, N; Xia, H; Punzmann, H; Shats, M

    2015-10-01

    Wave motion in disordered Faraday waves is analysed in terms of oscillons or quasi-particles. The motion of these oscillons is measured using particle tracking tools and it is compared with the motion of fluid particles on the water surface. Both the real floating particles and the oscillons, representing the collective fluid motion, show Brownian-type dispersion exhibiting ballistic and diffusive mean squared displacement at short and long times, respectively. While the floating particles motion has been previously explained in the context of two-dimensional turbulence driven by Faraday waves, no theoretical description exists for the random walk type motion of oscillons. It is found that the r.m.s velocity ⟨μ̃(osc)⟩(rms) of oscillons is directly related to the turbulent r.m.s. velocity ⟨μ̃⟩(rms) of the fluid particles in a broad range of vertical accelerations. The measured ⟨μ̃(osc)⟩(rms) accurately explains the broadening of the frequency spectra of the surface elevation observed in disordered Faraday waves. These results suggest that 2D turbulence is the driving force behind both the randomization of the oscillons motion and the resulting broadening of the wave frequency spectra. The coupling between wave motion and hydrodynamic turbulence demonstrated here offers new perspectives for predicting complex fluid transport from the knowledge of wave field spectra and vice versa.

  2. Infrared spectrum of the complex of formaldehyde with carbon dioxide in argon and nitrogen matrices

    NASA Technical Reports Server (NTRS)

    Van Der Zwet, G. P.; Allamandola, Louis J.; Baas, F.; Greenberg, J. M.

    1989-01-01

    The complex of formaldehyde with carbon dioxide has been studied by infrared spectroscopy in argon and nitrogen matrices. The shifts relative to the free species show that the complex is weak and similar in argon and nitrogen. The results give evidence for T-shaped complexes, which are isolated in several configurations. Some evidence is also presented which indicates that, in addition to the two well-known sites in argon, carbon dioxide can be trapped in a third site.

  3. Infrared spectrum of the complex of formaldehyde with carbon dioxide in argon and nitrogen matrices

    NASA Technical Reports Server (NTRS)

    Van Der Zwet, G. P.; Allamandola, Louis J.; Baas, F.; Greenberg, J. M.

    1989-01-01

    The complex of formaldehyde with carbon dioxide has been studied by infrared spectroscopy in argon and nitrogen matrices. The shifts relative to the free species show that the complex is weak and similar in argon and nitrogen. The results give evidence for T-shaped complexes, which are isolated in several configurations. Some evidence is also presented which indicates that, in addition to the two well-known sites in argon, carbon dioxide can be trapped in a third site.

  4. Active imaging system with Faraday filter

    SciTech Connect

    Snyder, J.J.

    1992-12-31

    This invention is comprised of an active imaging system which has a low to medium powered laser transmitter and a receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination wile eliminating solar background.

  5. Infrared Spectra of (CO2)2-OCS Complex: Infrared Observation of Two Distinct Barrel-Shaped Isomers

    NASA Astrophysics Data System (ADS)

    Norooz Oliaee, J.; Dehghany, M.; Mivehvar, F.; Moazzen-Ahmadi, N.; McKellar, A. R. W.

    2010-06-01

    Spectra of (CO2)2-OCS complex in the region of the OCS ν 1 fundamental (˜ 2062 cm-1) are observed using a tunable diode laser to probe a pulsed supersonic slit jet expansion. A previous microwave study of the complex by Peebles and Kuczkowskia gave a distorted triangular cylinder. The geometerical disposition of the three dimer faces of this trimer are quite similar to the slipped CO2 dimer, the lowest energy form of OCS-CO2 (isomer a), also observed and analyzed in the microwave region, and the higher energy form of OCS-CO2 (isomer b), first observed by our group in the infrared region. Here we report the observation and analysis of two infrared bands, corresponding to two distinct isomers of the (CO2)2-OCS complex. A band around 2058.8 cm-1 was assigned to isomer I, which is the same as that studied previously by microwave spectroscopy. A second band around 2051.7 cm-1 was assigned to a higher energy isomer of the complex, isomer II, has not been observed previously, but expected on the basis of ab initio calculations. Approximate structural parameters for this new isomer were obtained by means of isotopic substitution. In contrast to isomer I, the geometerical disposition of the faces containing OCS and CO2 in isomer II are similar to isomer b of the OCS-CO2 complex. S. A. Peebles and R. L. Kuczkowski, J. Chem. Phys. 109, 5277 (1998). S. E. Novick, R. D. Suenram, and F. J. Lovas, J. Chem. Phys. 88, 687 (1988). M. Dehghany, J. Nooroz Oliaee, M. Afshari, N. Moazzen-Ahmadi, and A. R. W. McKellar, J. Chem. Phys. 130, 224310 (2009). H. Valdés and J. A. Sordo, Int. J. Comput. Chem. 23, 444 (2002).

  6. Infrared Spectroscopy of the H2/HD/D2-O2 Van Der Waals Complexes

    NASA Astrophysics Data System (ADS)

    Raston, Paul; Bunn, Hayley

    2016-06-01

    Hydrogen is the most abundant element in the universe and oxygen is the third, so understanding the interaction between the two in their different forms is important to understanding astrochemical processes. The interaction between H2 and O2 has been explored in low energy scattering experiments and by far infrared synchrotron spectroscopy of the van der Waals complex. The far infrared spectra suggest a parallel stacked average structure with seven bound rotationally excited states. Here, we present the far infrared spectrum of HD/D2-O2 and the mid infrared spectrum of H2-O2 at 80 K, recorded at the infrared beamline facility of the Australian Synchrotron. We observed 'sharp' peaks in the mid infrared region, corresponding to the end over end rotation of H2-O2, that are comparatively noisier than analogous peaks in the far infrared where the synchrotron light is brightest. The larger reduced mass of HD and D2 compared to H2 is expected to result in more rotational bound states and narrower bands. The latest results in our ongoing efforts to explore this system will be presented. Y. Kalugina, et al., Phys. Chem. Chem. Phys. 14, 16458 (2012) S. Chefdeville et al. Science 341, 1094 (2013) H. Bunn et al. ApJ 799, 65 (2015)

  7. THE COMPUTED INFRARED SPECTRA OF A VARIETY OF [FePAH]{sup +} COMPLEXES: MID- AND FAR-INFRARED FEATURES

    SciTech Connect

    Simon, A.; Joblin, C.

    2010-03-20

    The effects of the pi-coordination of an Fe atom on the mid- and far-infrared spectra of a mixture of cationic polycyclic aromatic hydrocarbons (PAHs), e.g., pyrene (C{sub 16}H{sub 10}), anthanthrene (C{sub 22}H{sub 12}), coronene (C{sub 24}H{sub 12}), ovalene (C{sub 32}H{sub 14}), circumpyrene (C{sub 42}H{sub 16}), and circumcoronene (C{sub 54}H{sub 18}), are studied by Density Functional Theory based calculations. In the mid-infrared range (3-20 {mu}m), by comparison with the bare PAH{sup +} spectrum, we found (1) an increase of the intensity ratio of the C-H stretching and C-H out-of-plane bending bands with respect to the intense CC stretching band and (2) a shift of the band positions and a characteristic profile with a steep blue rise and an extended red tail for the CC stretching and CH out-of-plane bending bands. None of these features appears inconsistent with the observed aromatic infrared band spectrum. In the far-infrared range (lambda > 20 {mu}m), the presence of a pi-coordinated Fe atom induces many new bands as (1) some vibrational modes of the PAH are activated due to symmetry reduction and (2) new modes involving the motion of the Fe atom occur. In particular, an accumulation point due to the activation of the Fe-PAH stretching mode is observed at around 40 {mu}m. This range is suggested to contain the spectral fingerprint for the presence of [M-PAH]{sup +} (M=Fe, Si, Mg) complexes in the interstellar medium. Additional features in the [60-300] {mu}m range are found for complexes with large PAHs. The obtained results are discussed in the light of past, present, and future astronomical missions, among which are the Herschel Space Observatory and the SPICA telescope for the far-infrared domain.

  8. Infrared complex refractive index measurements and simulated reflection mode infrared absorption spectroscopy of shock-compressed polymer thin films.

    PubMed

    Moore, D S; McGrane, S D; Funk, D J

    2004-05-01

    Thin film interference effects complicate the interpretation of reflection-mode infrared absorption spectra obtained in shock-compressed thin film materials and must be carefully accounted for in any analysis attempting to unravel shock-induced energy transfer or reactivity. We have calculated such effects for spectrally simple model systems and also, to the extent possible, for real systems such as polymethylmethacrylate (PMMA) and nitrocellulose (NC). We have utilized angle-dependent infrared (IR) reflectometry to obtain the ambient spectral complex index for PMMA and NC for use in the calculations and to interpret experiments. A number of counter-intuitive spectral effects are observed versus film thickness and during uniaxial shock compression: absorption band shifts, changes of shape, and changes in both absolute and relative peak intensities. The film thickness effects can be predicted by thin film interference alone, while additional assumptions are required to predict the effects due to shock compression. Since it is very difficult to obtain the complex index in the shock state, we made very simple assumptions regarding the change in vibrational spectra upon shock load-ing. We illustrate general thin film interference effects that could be expected and compare them to experimental results for the antisymmetric NO2 stretch mode of NC.

  9. Effective optical Faraday rotations of semiconductor EuS nanocrystals with paramagnetic transition-metal ions.

    PubMed

    Hasegawa, Yasuchika; Maeda, Masashi; Nakanishi, Takayuki; Doi, Yoshihiro; Hinatsu, Yukio; Fujita, Koji; Tanaka, Katsuhisa; Koizumi, Hitoshi; Fushimi, Koji

    2013-02-20

    Novel EuS nanocrystals containing paramagnetic Mn(II), Co(II), or Fe(II) ions have been reported as advanced semiconductor materials with effective optical rotation under a magnetic field, Faraday rotation. EuS nanocrystals with transition-metal ions, EuS:M nanocrystals, were prepared by the reduction of the Eu(III) dithiocarbamate complex tetraphenylphosphonium tetrakis(diethyldithiocarbamate)europium(III) with transition-metal complexes at 300 °C. The EuS:M nanocrystals thus prepared were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroanalysis (ICP-AES), and a superconducting quantum interference device (SQUID) magnetometer. Enhanced Faraday rotations of the EuS:M nanocrystals were observed around 550 nm, and their enhanced spin polarization was estimated using electron paramagnetic resonance (EPR) measurements. In this report, the magneto-optical relationship between the Faraday rotation efficiency and spin polarization is discussed.

  10. Infrared intensities and charge mobility in hydrogen bonded complexes

    SciTech Connect

    Galimberti, Daria; Milani, Alberto; Castiglioni, Chiara

    2013-08-21

    The analytical model for the study of charge mobility in the molecules presented by Galimberti et al.[J. Chem. Phys. 138, 164115 (2013)] is applied to hydrogen bonded planar dimers. Atomic charges and charge fluxes are obtained from density functional theory computed atomic polar tensors and related first derivatives, thus providing an interpretation of the IR intensity enhancement of the X–H stretching band observed upon aggregation. Our results show that both principal and non-principal charge fluxes have an important role for the rationalization of the spectral behavior; moreover, they demonstrate that the modulation of the charge distribution during vibrational motions of the –XH⋯Y– fragment is not localized exclusively on the atoms directly involved in hydrogen bonding. With these premises we made some correlations between IR intensities, interaction energies, and charge fluxes. The model was tested on small dimers and subsequently to the bigger one cytosine-guanine. Thus, the model can be applied to complex systems.

  11. The gravitational analog of Faraday's induction law

    NASA Astrophysics Data System (ADS)

    Zile, Daniel; Overduin, James

    2015-04-01

    Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

  12. Michael Faraday and his contribution to anesthesia.

    PubMed

    Bergman, N A

    1992-10-01

    Michael Faraday (1791-1867) was a protégé of Humphry Davy. He became one of Davy's successors as Professor of Chemistry at the Royal Institution of Great Britain. Of Faraday's many brilliant discoveries in chemistry and physics, probably the best remembered today is his work on electromagnetic induction. Faraday's contribution to introduction of anesthesia was his published announcement in 1818 that inhalation of the vapor of ether produced the same effects on mentation and consciousness as the breathing of nitrous oxide. He most likely became familiar with the central nervous system effects of nitrous oxide through his association with Davy, an avid user of the gas. Sulfuric ether was a common, convenient, cheap, and easily available substance, in contrast to nitrous oxide, which required expensive, cumbersome, and probably not widely available apparatus for its production and administration. The capability for inhaling intoxicating vapors eventually became commonly available with the use of ether instead of the gas. The first surgical anesthetics were a consequence of the resulting student "ether frolics." The 1818 announcement on breathing ether vapor was published anonymously; however, notations in Faraday's handwriting in some of his personal books clearly establish Michael Faraday as the author of this brief communication.

  13. Faraday rotation measurement method and apparatus

    NASA Technical Reports Server (NTRS)

    Brockman, M. H. (Inventor)

    1981-01-01

    A method and device for measuring Faraday rotation of a received RF signal is described. A simultaneous orthogonal polarization receiver compensates for a 3 db loss due to splitting of a received signal into left circular and right circular polarization channels. The compensation is achieved by RF and modulation arraying utilizing a specific receiver array which also detects and measures Faraday rotation in the presence or absence of spin stabilization effects on a linear polarization vector. Either up-link or down-link measurement of Faraday rotation is possible. Specifically, the Faraday measurement apparatus utilized in conjunction with the specific receiver array provides a means for comparing the phase of a reference signal in the receiver array to the phase of a tracking loop signal related to the incoming signal, and comparing the phase of the reference signal to the phase of the tracking signal shifted in phase by 90 degrees. The averaged and unaveraged signals, are compared, the phase changes between the two signals being related to Faraday rotation.

  14. Faraday caustics. Singularities in the Faraday spectrum and their utility as probes of magnetic field properties

    NASA Astrophysics Data System (ADS)

    Bell, M. R.; Junklewitz, H.; Enßlin, T. A.

    2011-11-01

    We describe singularities in the distribution of polarized intensity as a function of Faraday depth (i.e. the Faraday spectrum) caused by line-of-sight (LOS) magnetic field reversals. We call these features Faraday caustics because of their similarity to optical caustics. They appear as sharply peaked and asymmetric profiles in the Faraday spectrum, that have a tail that extends to one side. The direction in which the tail extends depends on the way in which the LOS magnetic field reversal occurs (either changing from oncoming to retreating or vice versa). We describe how Faraday caustics will form three-dimensional surfaces that relate to boundaries between regions where the LOS magnetic field has opposite polarity. We present examples from simulations of the predicted polarized synchrotron emission from the Milky Way. We derive either the probability or luminosity distribution of Faraday caustics produced in a Gaussian magnetic field distribution as a function of their strength, ℱ, and find that for strong Faraday caustics P(ℱ) ∝ ℱ-3. If fully resolved, this distribution is also shown to depend on the Taylor microscale, which relates to the largest scale over which dissipation is important in a turbulent flow.

  15. Analytical estimation of solid angle subtended by complex well-resolved surfaces for infrared detection studies.

    PubMed

    Mahulikar, Shripad P; Potnuru, Santosh K; Kolhe, Pankaj S

    2007-08-01

    The solid angle (Omega) subtended by the hot power-plant surfaces of a typical fighter aircraft, on the detector of an infrared (IR) guided missile, is analytically obtained. The use of the parallel rays projection method simplifies the incorporation of the effect of the optical blocking by engine surfaces, on Omega-subtended. This methodology enables the evaluation of the relative contribution of the IR signature from well-resolved distributed sources, and is important for imaging infrared detection studies. The complex 3D surface of a rear fuselage is projected onto an equivalent planar area normal to the viewing aspect, which would give the same Omega-subtended.

  16. Infrared spectra and density functional theory calculations of the tantalum and niobium carbonyl dinitrogen complexes.

    PubMed

    Lu, Zhang-Hui; Jiang, Ling; Xu, Qiang

    2009-07-21

    Laser-ablated tantalum and niobium atoms react with CO and N(2) mixtures in excess neon to produce carbonyl metal dinitrogen complexes, NNMCO (M = Ta, Nb), (NN)(2)TaCO, and NNTa(CO)(2), as well as metal carbonyls and dinitrogen complexes. These carbonylmetal dinitrogen complexes are characterized using infrared spectroscopy on the basis of the results of the isotopic substitution and mixed isotopic splitting patterns. Density functional theory calculations have been performed on these novel species. The good agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these species from the matrix infrared spectra. Natural bond orbital analysis and plausible reaction mechanisms for the formation of the products are discussed.

  17. Faraday waves under time-reversed excitation.

    PubMed

    Pietschmann, Dirk; Stannarius, Ralf; Wagner, Christian; John, Thomas

    2013-03-01

    Do parametrically driven systems distinguish periodic excitations that are time mirrors of each other? Faraday waves in a Newtonian fluid are studied under excitation with superimposed harmonic wave forms. We demonstrate that the threshold parameters for the stability of the ground state are insensitive to a time inversion of the driving function. This is a peculiarity of some dynamic systems. The Faraday system shares this property with standard electroconvection in nematic liquid crystals [J. Heuer et al., Phys. Rev. E 78, 036218 (2008)]. In general, time inversion of the excitation affects the asymptotic stability of a parametrically driven system, even when it is described by linear ordinary differential equations. Obviously, the observed symmetry has to be attributed to the particular structure of the underlying differential equation system. The pattern selection of the Faraday waves above threshold, on the other hand, discriminates between time-mirrored excitation functions.

  18. Mode-locking via dissipative Faraday instability.

    PubMed

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-08-09

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  19. Calibrated Faraday Current And Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Neyer, B. T.; Chang, J.; Ruggles, L. E.

    1986-01-01

    We have developed a calibrated optical fiber Faraday rotation current sensor. A strong magnetic field in an optical fiber introduces circular birefringence, causing the plane of polarization of light to rotate by an amount proportional to the magnetic field. Faraday loops used in the past were nonlinear due to the stress-induced linear birefringence caused by bending the loop. This linear birefringence interfered with the Faraday rotation, yielding a complicated relationship between the current and detected light signal. We have found a way to overcome the effects of the unwanted linear birefringence and produce a calibrated current waveform. The calibration is limited only by the accurate knowledge of the Verdet constant of the optical fiber. Results of recent experiments as well as planned measurements will be presented.

  20. Mode-locking via dissipative Faraday instability

    PubMed Central

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-01-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin–Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system—spectrally dependent losses—achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin–Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708

  1. Mode-locking via dissipative Faraday instability

    NASA Astrophysics Data System (ADS)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  2. Faraday polarization fluctuations of satellite beacon signals

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Klobuchar, J. A.

    1988-01-01

    The anisotropic effects of random density irregularities in causing Faraday polarization fluctuations of VHF radio signals are examined, taking both rod-like and sheet-like irregularities into consideration. It is found that the variance of Faraday polarization fluctuations depends on the ratio of perpendicular to parallel correlation lengths. The anisotropic effect of rod-like ionospheric irregularities are shown to be most appreciable for longitudinal propagation. The anisotropic effect of sheet-like ionospheric irregularities, however, is not strongly dependent on the radio propagation angle. During transionospheric propagation at large angles with respect to the geomagnetic field, sheet-like irregularities may cause greater Faraday polarization fluctuations than rod-like irregularities.

  3. A study on the near-infrared luminescent properties of xerogel materials doped with dysprosium complexes.

    PubMed

    Feng, Jing; Zhou, Liang; Song, Shu-Yan; Li, Zhe-Feng; Fan, Wei-Qiang; Sun, Li-Ning; Yu, Ying-Ning; Zhang, Hong-Jie

    2009-09-07

    A series of dysprosium complex doped xerogels with the same first ligand (acac = acetylacetone) and different neutral ligands were synthesized in situ via a sol-gel process. The Fourier transform infrared (FTIR) spectra, diffuse reflectance (DR) spectra, and near-infrared (NIR) luminescent properties of dysprosium complexes and dysprosium complex doped xerogels are described in detail. The results reveal that the dysprosium complex is successfully synthesized in situ in the corresponding xerogel. Excitation at the maximum absorption wavelength of the ligands resulted in the characteristic NIR luminescence of the Dy3+ ion, which contributes to the energy transfer from the ligands to the central Dy3+ ion in both the dysprosium complexes and xerogels via an antenna effect. The NIR luminescent properties of the dysprosium complexes and xerogels were compared, respectively. The evidence showed that the neutral ligand triphenyl phosphine oxide (TPPO) could increase the emission intensity of the dysprosium complex while 1,10-phenanthroline (phen) gave the negative effect. In addition, the coordinated water molecules affect the emission intensity of the dysprosium complex doped xerogel without the neutral ligand.

  4. Rapid determination of Faraday rotation in optical glasses by means of secondary Faraday modulator.

    PubMed

    Sofronie, M; Elisa, M; Sava, B A; Boroica, L; Valeanu, M; Kuncser, V

    2015-05-01

    A rapid high sensitive method for determining the Faraday rotation of optical glasses is proposed. Starting from an experimental setup based on a Faraday rod coupled to a lock-in amplifier in the detection chain, two methodologies were developed for providing reliable results on samples presenting low and large Faraday rotations. The proposed methodologies were critically discussed and compared, via results obtained in transmission geometry, on a new series of aluminophosphate glasses with or without rare-earth doping ions. An example on how the method can be used for a rapid examination of the optical homogeneity of the sample with respect to magneto-optical effects is also provided.

  5. Ultrafast Faraday Rotation of Slow Light

    NASA Astrophysics Data System (ADS)

    Musorin, A. I.; Sharipova, M. I.; Dolgova, T. V.; Inoue, M.; Fedyanin, A. A.

    2016-08-01

    The active control of optical signals in the time domain is what science and technology demand in fast all-optical information processing. Nanostructured materials can modify the group velocity and slow the light down, as the artificial light dispersion emerges. We observe the ultrafast temporal behavior of the Faraday rotation within a single femtosecond laser pulse under conditions of slow light in a one-dimensional magnetophotonic crystal. The Faraday effect changes by 20% over the time of 150 fs. This might be applicable to the fast control of light in high-capacity photonic devices.

  6. Infrared spectroscopic studies on reaction induced conformational changes in the NADH ubiquinone oxidoreductase (complex I).

    PubMed

    Hellwig, Petra; Kriegel, Sébastien; Friedrich, Thorsten

    2016-07-01

    Redox-dependent conformational changes are currently discussed to be a crucial part of the reaction mechanism of the respiratory complex I. Specialized difference Fourier transform infrared techniques allow the detection of side-chain movements and minute secondary structure changes. For complex I, (1)H/(2)H exchange kinetics of the amide modes revealed a better accessibility of the backbone in the presence of NADH and quinone. Interestingly, the presence of phospholipids, that is crucial for the catalytic activity of the isolated enzyme complex, changes the overall conformation. When comparing complex I samples from different species, very similar electrochemically induced FTIR difference spectra and very similar rearrangements are reported. Finally, the information obtained with variants and from Zn(2+) inhibited samples for the conformational reorganization of complex I upon electron transfer are discussed in this review. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.

  7. Infrared spectra of new Re(III) complexes with thiourea derivatives.

    PubMed

    Gambino, Dinorah; Kremer, Eduardo; Baran, Enrique J

    2002-12-01

    Complexes of the type [Re(III)L6]X3, with L = thiourea, N-methylthiourea, N-ethylthiourea or N,N'-dimethytlthiourea and X = Cl- or PF6-, were prepared as suitable precursors for the synthesis of new rhenium complexes potentially useful in nuclear medicine. The infrared (IR) spectra of these complexes were recorded and analyzed and a general vibrational pattern for Re(III) complexes with thiourea derivatives could be established. Approximate assignments for N-allylthiourea and N-ethylthiourea are also proposed for the first time. The synthesis of the new complex [Re(III)(N-allylthiourea)6](PF6)3 is also reported, and information about its structural characteristics was obtained comparing its IR spectrum with those of the other complexes of the investigated series.

  8. Infrared Spectroscopy of Metal Ion Complexes: Models for Metal Ligand Interactions and Solvation

    NASA Astrophysics Data System (ADS)

    Duncan, Michael

    2006-03-01

    Weakly bound complexes of the form M^+-Lx (M=Fe, Ni, Co, etc.; L=CO2, C2H2, H2O, benzene, N2) are prepared in supersonic molecular beams by laser vaporization in a pulsed-nozzle cluster source. These species are mass analyzed and size-selected in a reflectron time-of-flight mass spectrometer. Clusters are photodissociated at infrared wavelengths with a Nd:YAG pumped infrared optical parametric oscillator/amplifier (OPO/OPA) laser or with a tunable infrared free-electron laser. M^+-(CO2)x complexes absorb near the free CO2 asymmetric stretch near 2349 cm-1 but with an interesting size dependent variation in the resonances. Small clusters have blue-shifted resonances, while larger complexes have additional bands due to surface CO2 molecules not attached to the metal. M^+(C2H2)n complexes absorb near the C-H stretches in acetylene, but resonances in metal complexes are red-shifted with repect to the isolated molecule. Ni^+ and Co^+ complexes with acetylene undergo intracluster cyclization reactions to form cyclobutadiene. Transition metal water complexes are studied in the O-H stretch region, and partial rotational structure can be measured. M^+(benzene) and M^+(benzene)2 ions (M=V, Ti, Al) represent half-sandwich and sandwich species, whose spectra are measured near the free benzene modes. These new IR spectra and their assignments will be discussed as well as other new IR spectra for similar complexes.

  9. THz near-field Faraday imaging in hybrid metamaterials.

    PubMed

    Kumar, Nishant; Strikwerda, Andrew C; Fan, Kebin; Zhang, Xin; Averitt, Richard D; Planken, Paul C M; Adam, Aurèle J L

    2012-05-07

    We report on direct measurements of the magnetic near-field of metamaterial split ring resonators at terahertz frequencies using a magnetic field sensitive material. Specifically, planar split ring resonators are fabricated on a single magneto-optically active terbium gallium garnet crystal. Normally incident terahertz radiation couples to the resonator inducing a magnetic dipole oscillating perpendicular to the crystal surface. Faraday rotation of the polarisation of a near-infrared probe beam directly measures the magnetic near-field with 100 femtosecond temporal resolution and (λ/200) spatial resolution. Numerical simulations suggest that the magnetic field can be enhanced in the plane of the resonator by as much as a factor of 200 compared to the incident field strength. Our results provide a route towards hybrid devices for dynamic magneto-active control of light such as isolators, and highlight the utility of split ring resonators as compact probes of magnetic phenomena in condensed matter.

  10. Infrared spectra of oxygen-rich yttrium and lanthanum dioxygen/ozonide complexes in solid argon.

    PubMed

    Gong, Yu; Ding, Chuanfan; Zhou, Mingfei

    2009-07-30

    The reactions of yttrium and lanthanum atoms with O(2) have been reinvestigated using matrix isolation infrared spectroscopy and theoretical calculations. The ground-state yttrium and lanthanum atoms react with O(2) to produce the inserted yttrium and lanthanum dioxide molecules as the initial products. The yttrium dioxide molecule interacts spontaneously with additional O(2) molecules to form the oxygen-rich OY(eta(2)-O(3)) complex and possibly the (eta(2)-O(2))Y(eta(2)-O(3))(2) complexes upon sample annealing, which can be regarded as the side-on bonded yttrium monoxide ozonide complex and the superoxo yttrium bisozonide complex, respectively. Visible irradiation induces the isomerization of the OY(eta(2)-O(3)) complex to the superoxo yttrium peroxide Y(eta(2)-O(2))(2) isomer, in which both the superoxo and peroxo ligands are side-on bonded to the yttrium center. The lanthanum dioxide molecule reacts with additional O(2) molecules to form the lanthanum dioxide-dioxygen complex with planar C(2v) symmetry, which rearranges to the lanthanum monoxide ozonide complex, OLa(eta(2)-O(3)), under near-infrared excitation.

  11. A fast detection method for small weak infrared target in complex background

    NASA Astrophysics Data System (ADS)

    Lei, Bo; Wang, Bo; Sun, Gangbo; Xu, Yin; Hong, Pu; Liu, Chongcheng; Yue, Song

    2016-11-01

    Small target is also weak target, which is likely to be a threat to the observation platform. So small target detection is an important task for many automatic object detection system. Otherwise, small target detection is a challenge for many complex scenes because of the low SNR and sophisticated background. This paper introduced a fast and effective method for small target detection in infrared scene with complex background, which is suitable for missile guidance and menace warning. Firstly, a template is created to detect the local maxima in the image. Secondly, a constrained double criteria region growth algorithm is performed to form separate regions. Finally, extracted regions are selected by a small round target filter, after which, the remaining connected regions are considered to be detected small targets. The proposed algorithm was applied on videos captured by cooled infrared imagers. Experimental results show the method introduced in this paper is efficient and effective, which is suitable for time sensitive automatic target detection.

  12. Water complexes of important air pollutants: geometries, complexation energies, concentrations, infrared spectra, and intrinsic reactivity.

    PubMed

    Galano, Annia; Narciso-Lopez, Marcela; Francisco-Marquez, Misaela

    2010-05-13

    Water complexes involving methanol, ethanol, formaldehyde, formic acid, acetone, ammonia, acetylene, ethylene, chloroethene, trichloroethene, 1,1,1-trichloroethane, hydroxyl radical, and hydroperoxyl radical have been studied. Enthalpies, entropies, and Gibbs free energies of association have been estimated, as well as the concentrations of the complexes under lower-troposphere conditions. The influence of the relative air humidity on the complexation processes has been analyzed. The association processes yielding water complexes of methanol, ethanol, formic acid, ammonia, acetone, hydroxyl radical, and hydroperoxyl radical were found to be more exothermic than that of the water dimer. General trends for the reactivity of the studied water complexes, compared to those of the corresponding free species, are proposed based on global reactivity indexes. The previously reported increased reactivity of the (*)OOH self-reaction, when there is water present, has been explained. The IR spectra of the complexes have been analyzed and compared with those of the free species.

  13. The Minus Sign in Faraday's Law Revisited

    ERIC Educational Resources Information Center

    O'Sullivan, Colm; Hurley, Donal

    2013-01-01

    By introducing the mathematical concept of orientation, the significance of the minus sign in Faraday's law may be made clear to students with some knowledge of vector calculus. For many students, however, the traditional approach of treating the law as a relationship between positive scalars and of relying on Lenz's law to provide the information…

  14. Fiber optic, Faraday rotation current sensor

    SciTech Connect

    Veeser, L.R.; Day, G.W.

    1986-01-01

    At the Second Megagauss Conference in 1979, there were reports of experiments that used the Faraday magneto-optic effect in a glass rod to measure large electric current pulses or magnetic fields. Since then we have seen the development of single-mode optical fibers that can carry polarized light in a closed loop around a current load. A fiber optic Faraday rotation sensor will integrate the flux, instead of sampling it at a discrete point, to get a measurement independent of the current distribution. Early Faraday rotation experiments using optical fibers to measure currents dealt with problems such as fiber birefringence and difficulties in launching light into the tiny fiber cores. We have built on those experiments, working to reduce the effects of shocks and obtaining higher bandwidths, absolute calibration, and computerized recording and data analysis, to develop the Faraday rotation sensors into a routine current diagnostic. For large current pulses we find reduced sensitivity to electromagnetic interference and other backgrounds than for Rogowski loops; often the fiber optic sensors are useful where conductive probes cannot be used at all. In this paper we describe the fiber optic sensors and some practical matters involved in fielding them.

  15. The Minus Sign in Faraday's Law Revisited

    ERIC Educational Resources Information Center

    O'Sullivan, Colm; Hurley, Donal

    2013-01-01

    By introducing the mathematical concept of orientation, the significance of the minus sign in Faraday's law may be made clear to students with some knowledge of vector calculus. For many students, however, the traditional approach of treating the law as a relationship between positive scalars and of relying on Lenz's law to provide the information…

  16. Reflections of a Faraday Challenge Day Leader

    ERIC Educational Resources Information Center

    Sewell, Keira

    2014-01-01

    Keira Sewell has just finished her second year as a Challenge Leader for the Faraday Challenge, a STEM-based scheme run by the Institution of Engineering and Technology. Aimed at 12-13 year-old students, its purpose is to engage students in future careers in engineering. Each year, a new challenge is held in over sixty schools and universities…

  17. QUANTUM ELECTRONIC DEVICES: Cryogenic Faraday isolator

    NASA Astrophysics Data System (ADS)

    Zheleznov, D. S.; Zelenogorskii, V. V.; Katin, E. V.; Mukhin, I. B.; Palashov, O. V.; Khazanov, Efim A.

    2010-05-01

    A Faraday isolator is described in which thermal effects are suppressed by cooling down to liquid nitrogen temperatures. The principal scheme, main characteristics and modifications of the isolator are presented. The isolation degree is studied experimentally for the subkilowatt average laser radiation power. It is shown that the isolator can be used at radiation powers up to tens of kilowatts.

  18. Fast Faraday Cup With High Bandwidth

    SciTech Connect

    Deibele, Craig E

    2006-03-14

    A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

  19. Reflections of a Faraday Challenge Day Leader

    ERIC Educational Resources Information Center

    Sewell, Keira

    2014-01-01

    Keira Sewell has just finished her second year as a Challenge Leader for the Faraday Challenge, a STEM-based scheme run by the Institution of Engineering and Technology. Aimed at 12-13 year-old students, its purpose is to engage students in future careers in engineering. Each year, a new challenge is held in over sixty schools and universities…

  20. Faraday current sensing employing chromatic modulation

    NASA Astrophysics Data System (ADS)

    Jones, G. R.; Li, G.; Spencer, J. W.; Aspey, R. A.; Kong, M. G.

    1998-01-01

    Faraday current sensors using a variety of sensing elements have been investigated extensively for their high sensitivity as well as other advantages [G.L. Lewis et al., Proc. IEE Conf. on The Reliability of Transmission and Distribution Equipment, 1995; Y.N. Ning et al., Optics Lett. 16 (1991); C.M.M. van den Tempel, Appl. Optics 32 (1993)]. Concurrently chromatic modulation techniques have been investigated at the University of Liverpool for use with optical fibre sensors of different types [N.A. Pilling, Ph.D. Thesis, 1992; M.M. Murphy, Ph.D. Thesis, 1991] including Faraday current sensing, for overcoming difficulties with non-referenced intensity modulation systems. In this contribution a brief discussion of the scope of chromatically based Faraday current sensing with particular regard to electric power transmission and distribution industries is given. A novel sensor based upon a Faraday glass block in combination with a BSO crystal in the sensing element is described. The sensor takes advantage of the natural gyrotropy of the BSO which conversely has been previously regarded as a disadvantage. The experimental results obtained indicate that this method offers a novel approach to improving system sensitivity. The extension of the approach from a simple bench top demonstrator to real power systems deployment is also discussed.

  1. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  2. Infrared consequence spectroscopy of gaseous protonated and metal ion cationized complexes.

    PubMed

    Fridgen, Travis D

    2009-01-01

    In this article, the new and exciting techniques of infrared consequence spectroscopy (sometimes called action spectroscopy) of gaseous ions are reviewed. These techniques include vibrational predissociation spectroscopy and infrared multiple photon dissociation spectroscopy and they typically complement one another in the systems studied and the information gained. In recent years infrared consequence spectroscopy has provided long-awaited direct evidence into the structures of gaseous ions from organometallic species to strong ionic hydrogen bonded structures to large biomolecules. Much is being learned with respect to the structures of ions without their stabilizing solvent which can be used to better understand the effect of solvent on their structures. This review mainly covers the topics with which the author has been directly involved in research: structures of proton-bound dimers, protonated amino acids and DNA bases, amino acid and DNA bases bound to metal ions and, more recently, solvated ionic complexes. It is hoped that this review reveals the impact that infrared consequence spectroscopy has had on the field of gaseous ion chemistry.

  3. Characterization of a Carbon Dioxide-Hexaflourobenzene Complex Using Matrix Isolation Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Amicangelo, Jay C.; Gall, Bradley K.; Horn, Maryn N.

    2017-06-01

    Matrix isolation infrared spectroscopy was used to characterize a 1:1 complex of carbon dioxide (CO_2) with hexaflourobenzene (C_6F_6). Co-deposition experiments with CO_2 and {_6F_6} were performed at 20 K using argon as the matrix gas. New infrared peaks attributable to the CO_2-C_6F_6 complex were observed near the O-C-O antisymmetric stretching vibration of the CO_2 monomer and near the C-F stretching vibration of the C_6F_6 monomer. The initial identification of the newly observed infrared peaks to those of a CO_2-C_6F_6 complex was established by performing several concentration studies in which the sample-to-matrix ratios of the monomers were varied between 1:100 to 1:1600, by comparing the resulting co-deposition spectra with the spectra of the individual monomers, and by matrix annealing experiments (30 - 35 K). Co-deposition experiments were also performed using isotopically labeled carbon dioxide (^{13}CO_2) and the analogous peaks for the ^{13}CO_2-C_6F_6 complex were observed. Quantum chemical calculations were performed for the CO_2-C_6F_6 complex at the MP2/aug-cc-pVDZ level of theory in order to explore the intermolecular potential energy surface of the complex and to obtain optimized complex geometries and predicted vibrational frequencies of the complex. The calculations for the exploration of the potential energy surface involved rigid scans along the intermolecular distance and various angle coordinates for several general orientations of the two monomers. Based on these calculations, full geometry optimizations were then performed and two stable complex minima were found: one in which the CO_2 is perpendicular and centered to the C_6F_6 ring (ΔE_{int} = -7.9 kJ/mol) and one in which the CO_2 is parallel to the C_6F_6 ring but displaced from the center (ΔE_{int} = -6.0 kJ/mol). Comparing the predicted vibrational spectra for both complexes to the observed experimental spectra, particularly for the O-C-O antisymmetric stretching region, it is

  4. Faraday Rotation Measure Synthesis of Intermediate Redshift Quasars as a Probe of Intervening Matter

    NASA Astrophysics Data System (ADS)

    Kim, Kwang Seong; Lilly, Simon J.; Miniati, Francesco; Bernet, Martin L.; Beck, Rainer; O'Sullivan, Shane P.; Gaensler, Bryan M.

    2016-10-01

    There is evidence that magnetized material along the line of sight to distant quasars is detectable in the polarization properties of the background sources. The polarization properties appear to be correlated with the presence of intervening Mg ii absorption, which is thought to arise in outflowing material from star forming galaxies. In order to investigate this further, we have obtained high spectral resolution polarization measurements, with the Very Large Array and the Australia Telescope Compact Array, of a set of 49 unresolved quasars for which we have high quality optical spectra. These enable us to produce a Faraday Depth spectrum for each source, using Rotation Measure (RM) Synthesis. Our new independent radio data confirms that interveners are strongly associated with depolarization. We characterize the complexity of the Faraday Depth spectrum using a number of parameters and show how these are related, or not, to the depolarization and to the presence of Mg ii absorption along the line of sight. We argue that complexity and structure in the Faraday Depth distribution likely arise from both intervening material and intrinsically to the background source and attempt to separate these. We find that the strong radio depolarization effects associated with intervening material at redshifts out to z≈ 1 arise from inhomogeneous Faraday screens producing a dispersion in RM across individual sources of around 10 rad m-2. This is likely produced by disordered fields with strengths of at least 3 μG.

  5. Infrared Multiple-Photon Dissociation spectroscopy of group II metal complexes with salicylate

    SciTech Connect

    Ryan P. Dain; Gary Gresham; Gary S. Groenewold; Jeffrey D. Steill; Jos Oomens; Michael J. van Stipdonk

    2011-07-01

    Ion-trap tandem mass spectrometry with collision-induced dissociation, and the combination of infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) calculations were used to characterize singly-charged, 1:1 complexes of Ca2+, Sr2+ and Ba2+ with salicylate. For each metal-salicylate complex, the CID pathways are: (a) elimination of CO2 and (b) formation of [MOH]+ where M=Ca2+, Sr2+ or Ba2+. DFT calculations predict three minima for the cation-salicylate complexes which differ in the mode of metal binding. In the first, the metal ion is coordinated by O atoms of the (neutral) phenol and carboxylate groups of salicylate. In the second, the cation is coordinated by phenoxide and (neutral) carboxylic acid groups. The third mode involves coordination by the carboxylate group alone. The infrared spectrum for the metal-salicylate complexes contains a number of absorptions between 1000 – 1650 cm-1, and the best correlation between theoretical and experimental spectra for the structure that features coordination of the metal ion by phenoxide and the carbonyl group of the carboxylic acid group, consistent with calculated energies for the respective species.

  6. NEAR-INFRARED POLARIMETRY OF A NORMAL SPIRAL GALAXY VIEWED THROUGH THE TAURUS MOLECULAR CLOUD COMPLEX

    SciTech Connect

    Clemens, Dan P.; Cashman, L. R.; Pavel, M. D. E-mail: pavelmi@utexas.edu

    2013-03-15

    Few normal galaxies have been probed using near-infrared polarimetry, even though it reveals magnetic fields in the cool interstellar medium better than either optical or radio polarimetry. Deep H-band (1.6 {mu}m) linear imaging polarimetry toward Taurus serendipitously included the galaxy 2MASX J04412715+2433110 with adequate sensitivity and resolution to map polarization across nearly its full extent. The observations revealed the galaxy to be a steeply inclined ({approx}75 Degree-Sign ) disk type with a diameter, encompassing 90% of the Petrosian flux, of 4.2 kpc at a distance of 53 Mpc. Because the sight line passes through the Taurus Molecular Cloud complex, the foreground polarization needed to be measured and removed. The foreground extinction A{sub V} of 2.00 {+-} 0.10 mag and reddening E(H - K) of 0.125 {+-} 0.009 mag were also assessed and removed, based on analysis of Two Micron All Sky Survey, UKIRT Infrared Deep Sky Survey, Spitzer, and Wide-field Infrared Survey Explorer photometry using the Near-Infrared Color Excess, NICE-Revisited, and Rayleigh-Jeans Color Excess methods. Corrected for the polarized foreground, the galaxy polarization values range from 0% to 3%. The polarizations are dominated by a disk-parallel magnetic field geometry, especially to the northeast, while either a vertical field or single scattering of bulge light produces disk-normal polarizations to the southwest. The multi-kiloparsec coherence of the magnetic field revealed by the infrared polarimetry is in close agreement with short-wavelength radio synchrotron observations of edge-on galaxies, indicating that both cool and warm interstellar media of disk galaxies may be threaded by common magnetic fields.

  7. Faraday-effect polarimeter-interferometer system for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Li, W. M.; Wang, Z. X.; Qian, J. P.; Yang, Y.; Zeng, L.; Lan, T.; Wei, X. C.; Li, G. S.; Hu, L. Q.; Wan, B. N.

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (˜2°), and the Faraday rotation angle rms phase noise is <0.1°.

  8. Faraday effect improvement by Dy3+-doping of terbium gallium garnet single crystal

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Yang, Lei; Hang, Yin; Wang, Xiangyong

    2016-01-01

    Highly transparent Dy3+-doped terbium gallium garnet (TGG) single crystal was grown by Czochralski (Cz) method. Phase composition of the crystal was tested by XRD measurements. The distribution coefficient of Dy3+ in the crystal was obtained. The optical and magneto-optical properties were analyzed in detail, and magnetic properties of the Dy3+-TGG crystal were studied. The paramagnetic behavior is observed down to 10 K. The as-grown crystal exhibited high optical transmittance, particularly in the visible region. The Faraday rotation was investigated over visible and near-infrared regions (VIS-NIR) at room temperature. The Verdet constants increase at measured wavelengths and high thermal stability was found in Dy3+-doped TGG, as compared to the properties of pure TGG, indicating that Dy3+-doped crystals are preferable for magneto-active materials used in Faraday devices at VIS-NIR wavelengths.

  9. Faraday-effect polarimeter-interferometer system for current density measurement on EAST.

    PubMed

    Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Zou, Z Y; Li, W M; Wang, Z X; Qian, J P; Yang, Y; Zeng, L; Lan, T; Wei, X C; Li, G S; Hu, L Q; Wan, B N

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10(16) m(-2) (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

  10. Faraday-effect polarimeter-interferometer system for current density measurement on EAST

    SciTech Connect

    Liu, H. Q.; Jie, Y. X. Zou, Z. Y.; Li, W. M.; Wang, Z. X.; Qian, J. P.; Yang, Y.; Zeng, L.; Wei, X. C.; Hu, L. Q.; Wan, B. N.; Ding, W. X.; Brower, D. L.; Lan, T.; Li, G. S.

    2014-11-15

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10{sup 16} m{sup −2} (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

  11. Infrared Spectroscopy of NaCl(CH3OH)n Complexes in Helium Nanodroplets.

    PubMed

    Sadoon, Ahmed M; Sarma, Gautam; Cunningham, Ethan M; Tandy, Jon; Hanson-Heine, Magnus W D; Besley, Nicholas A; Yang, Shengfu; Ellis, Andrew M

    2016-10-10

    Infrared (IR) spectra of complexes between NaCl and methanol have been recorded for the first time. These complexes were formed in liquid helium nanodroplets by consecutive pick-up of NaCl and CH3OH molecules. For the smallest NaCl(CH3OH)n, complexes where n = 1-3, the IR data suggest that the lowest-energy isomer is the primary product in each case. The predominant contribution to the binding comes from ionic hydrogen bonds between the OH in each methanol molecule and the chloride ion in the NaCl, as established by the large red shift of the OH stretching bands compared with the isolated CH3OH molecule. For n ≥ 4, there is a dramatic shift from discrete vibrational bands to very broad absorption envelopes, suggesting a profound change in the structural landscape and, in particular, access to multiple low-energy isomers.

  12. Infrared spectroscopy of ozone-water complex in a neon matrix.

    PubMed

    Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko

    2007-05-10

    Matrix isolation infrared spectroscopy has been applied to study an ozone-water complex of atmospheric interest. The complex was identified in the spectral region of three normal modes of ozone and water. Ab initio calculation at MP4(SDQ), QCISD, and CCSD(T) levels indicates the existence of only one stable conformer, which accords with the present experimental result. This conformer belongs to the Cs symmetry group where two molecular planes of ozone and water are perpendicular to the Cs symmetry plane. The binding energy was calculated to be 1.89 kcal/mol at the CCSD(T)/6-311++G(3df,3pd)//CCSD(T)/6-311++G(d,p) level of theory. The formation constant and atmospheric abundance of the ozone-water complex are estimated using the thermodynamic and spectroscopic data obtained.

  13. Faraday-Michelson system for quantum cryptography.

    PubMed

    Mo, Xiao-Fan; Zhu, Bing; Han, Zheng-Fu; Gui, You-Zhen; Guo, Guang-Can

    2005-10-01

    Quantum key distribution provides unconditional security for communication. Unfortunately, current experimental schemes are not suitable for long-distance fiber transmission because of phase drift or Rayleigh backscattering. In this Letter we present a unidirectional intrinsically stable scheme that is based on Michelson-Faraday interferometers, in which ordinary mirrors are replaced with 90 degree Faraday mirrors. With the scheme, a demonstration setup was built and excellent stability of interference fringe visibility was achieved over a fiber length of 175 km. Through a 125 km long commercial communication fiber cable between Beijing and Tianjin, the key exchange was performed with a quantum bit-error rate of less than 6%, which is to our knowledge the longest reported quantum key distribution experiment under field conditions.

  14. In-vacuum Faraday isolation remote tuning.

    PubMed

    Accadia, T; Acernese, F; Antonucci, F; Aoudia, S; Arun, K G; Astone, P; Ballardin, G; Barone, F; Barsuglia, M; Bauer, Th S; Beker, M G; Bigotta, S; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Boccara, C; Bondu, F; Bonelli, L; Bosi, L; Braccini, S; Bradaschia, C; Brillet, A; Brisson; Budzynski, R; Bulik, T; Bulten, H J; Buskulic, D; Cagnoli, G; Calloni, E; Campagna, E; Canuel, B; Carbognani, F; Cavalier, F; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chincarini, A; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Corda, C; Corsi, A; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; Day, R; De Rosa, R; del Prete, M; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Dietz, A; Drago, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Franc, J; Frasca, S; Frasconi, F; Freise, A; Gammaitoni, L; Garufi, F; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Gouaty, R; Granata, M; Greverie, C; Guidi, G M; Heitmann, H; Hello, P; Hild, S; Huet, D; Jaranowski, P; Kowalska, I; Królak, A; La Penna, P; Leroy, N; Letendre, N; Li, T G F; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Michel, C; Milano, L; Minenkov, Y; Mohan, M; Moreau, J; Morgado, N; Morgia, A; Mosca, S; Moscatelli, V; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palladino, L; Palomba, C; Paoletti, F; Pardi, S; Parisi, M; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Pichot, M; Piergiovanni, F; Pietka, M; Pinard, L; Poggiani, R; Prato, M; Prodi, G A; Punturo, M; Puppo, P; Rabaste, O; Rabeling, D S; Rapagnani, P; Re, V; Regimbau, T; Ricci, F; Robinet, F; Rocchi, A; Rolland, L; Romano, R; Rosińska, D; Ruggi, P; Sassolas, B; Sentenac, D; Sturani, R; Swinkels, B; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Trummer, J; Vajentei, G; van den Brand, J F J; van der Putten, S; Vavoulidis, M; Vedovato, G; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Was, M; Yvert, M

    2010-09-01

    In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.

  15. On intracluster Faraday rotation. II - Statistical analysis

    NASA Technical Reports Server (NTRS)

    Lawler, J. M.; Dennison, B.

    1982-01-01

    The comparison of a reliable sample of radio source Faraday rotation measurements seen through rich clusters of galaxies, with sources seen through the outer parts of clusters and therefore having little intracluster Faraday rotation, indicates that the distribution of rotation in the former population is broadened, but only at the 80% level of statistical confidence. Employing a physical model for the intracluster medium in which the square root of magnetic field strength/turbulent cell per gas core radius number ratio equals approximately 0.07 microgauss, a Monte Carlo simulation is able to reproduce the observed broadening. An upper-limit analysis figure of less than 0.20 microgauss for the field strength/turbulent cell ratio, combined with lower limits on field strength imposed by limitations on the Compton-scattered flux, shows that intracluster magnetic fields must be tangled on scales greater than about 20 kpc.

  16. Faraday's first dynamo: An alternate analysis

    NASA Astrophysics Data System (ADS)

    Redinz, José Arnaldo

    2015-02-01

    The steady-state charge densities, electric potential, and current densities are determined analytically in the case of the first dynamo created by Michael Faraday, which consists of a conducting disk rotating between the poles of an off-axis permanent magnet. The results obtained are compared with another work that considered the same problem using a different approach. We also obtain analytical expressions for the total current on the disk and for the dynamo's electromotive force.

  17. Mid-infrared Complex Refractive Indices for Long-chain Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Niedziela, R. F.; Argon, P.; Edwards, M.; Roman, B.

    2016-12-01

    Frequency-dependent complex refractive indices, when coupled with an appropriate optical model, can be used to predict the scattering and absorption properties of particulate matter. Conversely, such refractive indices can be used to obtain basic physical information from an ensemble of particles through a suitable retrieval method. Physical quantities such as particle size, shape, and composition, for example, may be obtained from a careful analysis of aerosol extinction spectra. While refractive index data sets are available for some organic compounds in the literature, there is a lack of such sets for long-chain hydrocarbons. In this presentation, we report on the retrieval of complex refractive indices for squalane (C30H62) and squalene (C30H50) in the mid-infrared from their respective aerosol extinction spectra. Both compounds are used commercially, however, they can also be used as proxies for atmospheric aerosols in laboratory studies. In addition, we will present early results on the optical properties of motor oil aerosols and their relationship to those of other hydrocarbons. The included image shows a snapshot of the complex refractive indices for squalane across the mid-infrared.

  18. Continuous probing of cold complex molecules with infrared frequency comb spectroscopy.

    PubMed

    Spaun, Ben; Changala, P Bryan; Patterson, David; Bjork, Bryce J; Heckl, Oliver H; Doyle, John M; Ye, Jun

    2016-05-26

    For more than half a century, high-resolution infrared spectroscopy has played a crucial role in probing molecular structure and dynamics. Such studies have so far been largely restricted to relatively small and simple systems, because at room temperature even molecules of modest size already occupy many millions of rotational/vibrational states, yielding highly congested spectra that are difficult to assign. Targeting more complex molecules requires methods that can record broadband infrared spectra (that is, spanning multiple vibrational bands) with both high resolution and high sensitivity. However, infrared spectroscopic techniques have hitherto been limited either by narrow bandwidth and long acquisition time, or by low sensitivity and resolution. Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) combines the inherent broad bandwidth and high resolution of an optical frequency comb with the high detection sensitivity provided by a high-finesse enhancement cavity, but it still suffers from spectral congestion. Here we show that this problem can be overcome by using buffer gas cooling to produce continuous, cold samples of molecules that are then subjected to CE-DFCS. This integration allows us to acquire a rotationally resolved direct absorption spectrum in the C-H stretching region of nitromethane, a model system that challenges our understanding of large-amplitude vibrational motion. We have also used this technique on several large organic molecules that are of fundamental spectroscopic and astrochemical relevance, including naphthalene, adamantane and hexamethylenetetramine. These findings establish the value of our approach for studying much larger and more complex molecules than have been probed so far, enabling complex molecules and their kinetics to be studied with orders-of-magnitude improvements in efficiency, spectral resolution and specificity.

  19. Continuous probing of cold complex molecules with infrared frequency comb spectroscopy

    NASA Astrophysics Data System (ADS)

    Spaun, Ben; Changala, P. Bryan; Patterson, David; Bjork, Bryce J.; Heckl, Oliver H.; Doyle, John M.; Ye, Jun

    2016-05-01

    For more than half a century, high-resolution infrared spectroscopy has played a crucial role in probing molecular structure and dynamics. Such studies have so far been largely restricted to relatively small and simple systems, because at room temperature even molecules of modest size already occupy many millions of rotational/vibrational states, yielding highly congested spectra that are difficult to assign. Targeting more complex molecules requires methods that can record broadband infrared spectra (that is, spanning multiple vibrational bands) with both high resolution and high sensitivity. However, infrared spectroscopic techniques have hitherto been limited either by narrow bandwidth and long acquisition time, or by low sensitivity and resolution. Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) combines the inherent broad bandwidth and high resolution of an optical frequency comb with the high detection sensitivity provided by a high-finesse enhancement cavity, but it still suffers from spectral congestion. Here we show that this problem can be overcome by using buffer gas cooling to produce continuous, cold samples of molecules that are then subjected to CE-DFCS. This integration allows us to acquire a rotationally resolved direct absorption spectrum in the C-H stretching region of nitromethane, a model system that challenges our understanding of large-amplitude vibrational motion. We have also used this technique on several large organic molecules that are of fundamental spectroscopic and astrochemical relevance, including naphthalene, adamantane and hexamethylenetetramine. These findings establish the value of our approach for studying much larger and more complex molecules than have been probed so far, enabling complex molecules and their kinetics to be studied with orders-of-magnitude improvements in efficiency, spectral resolution and specificity.

  20. Midplane Faraday Rotation: A densitometer for BPX

    SciTech Connect

    Jobes, F.C.; Mansfield, D.K.

    1992-02-01

    The density in a high field, high density tokamak such as BPX can be determined by measuring the Faraday rotation of a 10.6 {mu}m laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then n{sub e}(R) can be readily obtained with a simple Abel version about the center line of the tokamak. For BPX operated at full field and density, the rotation angle would be quite large -- about 75{degrees} per pass. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 ``fringe,`` the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that BPX would be well served even at low densities by a Midplane Faraday Rotation densitometer of {approximately}64 channels. Both TFTR and PBX-M would be suitable test beds for the BPX system.

  1. Midplane Faraday Rotation: A densitometer for BPX

    SciTech Connect

    Jobes, F.C.; Mansfield, D.K.

    1992-02-01

    The density in a high field, high density tokamak such as BPX can be determined by measuring the Faraday rotation of a 10.6 {mu}m laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then n{sub e}(R) can be readily obtained with a simple Abel version about the center line of the tokamak. For BPX operated at full field and density, the rotation angle would be quite large -- about 75{degrees} per pass. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 fringe,'' the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that BPX would be well served even at low densities by a Midplane Faraday Rotation densitometer of {approximately}64 channels. Both TFTR and PBX-M would be suitable test beds for the BPX system.

  2. A Near-infrared Survey of the Rosette Complex: Clues of Early Cluster Evolution

    NASA Astrophysics Data System (ADS)

    Román-Zúñiga, Carlos G.; Lada, Elizabeth A.; Ferreira, Bruno

    2008-05-01

    The majority of stars in our galaxy are born in embedded clusters, which can be considered the fundamental units of star formation. We have recently surveyed the star forming content of the Rosette Complex using FLAMINGOS in order to investigate the properties of its embedded clusters. We discuss the results of our near-infrared imaging survey. In particular, we on the first evidence for the early evolution and expansion of the embedded clusters. In addition we present data suggesting a temporal sequence of cluster formation across the cloud and discuss the influence of the HII region on the star forming history of the Rosette.

  3. Matrix isolation infrared spectra of hydrogen halide and halogen complexes with nitrosyl halides

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.; Lucas, Donald; Pimentel, George C.

    1982-01-01

    Matrix isolation infrared spectra of nitrosyl halide (XNO) complexes with HX and X2 (X = Cl, Br) are presented. The relative frequency shifts of the HX mode are modest (ClNO H-Cl, delta-nu/nu = -0.045; BrNO H-Br, delta-nu/nu = -0.026), indicating weak hydrogen bonds 1-3 kcal/mol. These shifts are accompanied by significant shifts to higher frequencies in the XN-O stretching mode (CIN-O HCl, delta-nu/nu = +0.016; BrN-O HBr, delta-nu/nu = +0.011). Similar shifts were observed for the XN-O X2 complexes (ClN-O Cl2, delta-nu/nu = +0.009; BrN-O-Br2, delta-nu/nu = +0.013). In all four complexes, the X-NO stretching mode relative shift is opposite in sign and about 1.6 times that of the NO stretching mode. These four complexes are considered to be similar in structure and charge distribution. The XN-O frequency shift suggests that complex formation is accompanied by charge withdrawal from the NO bond ranging from about .04 to .07 electron charges. The HX and X2 molecules act as electron acceptors, drawing electrons out of the antibonding orbital of NO and strengthening the XN-O bond. The implications of the pattern of vibrational shifts concerning the structure of the complexes are discussed.

  4. Matrix isolation infrared spectra of hydrogen halide and halogen complexes with nitrosyl halides

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.; Lucas, Donald; Pimentel, George C.

    1982-01-01

    Matrix isolation infrared spectra of nitrosyl halide (XNO) complexes with HX and X2 (X = Cl, Br) are presented. The relative frequency shifts of the HX mode are modest (ClNO H-Cl, delta-nu/nu = -0.045; BrNO H-Br, delta-nu/nu = -0.026), indicating weak hydrogen bonds 1-3 kcal/mol. These shifts are accompanied by significant shifts to higher frequencies in the XN-O stretching mode (CIN-O HCl, delta-nu/nu = +0.016; BrN-O HBr, delta-nu/nu = +0.011). Similar shifts were observed for the XN-O X2 complexes (ClN-O Cl2, delta-nu/nu = +0.009; BrN-O-Br2, delta-nu/nu = +0.013). In all four complexes, the X-NO stretching mode relative shift is opposite in sign and about 1.6 times that of the NO stretching mode. These four complexes are considered to be similar in structure and charge distribution. The XN-O frequency shift suggests that complex formation is accompanied by charge withdrawal from the NO bond ranging from about .04 to .07 electron charges. The HX and X2 molecules act as electron acceptors, drawing electrons out of the antibonding orbital of NO and strengthening the XN-O bond. The implications of the pattern of vibrational shifts concerning the structure of the complexes are discussed.

  5. Theory of Kerr and Faraday rotations and linear dichroism in Topological Weyl Semimetals.

    PubMed

    Kargarian, Mehdi; Randeria, Mohit; Trivedi, Nandini

    2015-08-03

    We consider the electromagnetic response of a topological Weyl semimetal (TWS) with a pair of Weyl nodes in the bulk and corresponding Fermi arcs in the surface Brillouin zone. We compute the frequency-dependent complex conductivities σαβ(ω) and also take into account the modification of Maxwell equations by the topological θ-term to obtain the Kerr and Faraday rotations in a variety of geometries. For TWS films thinner than the wavelength, the Kerr and Faraday rotations, determined by the separation between Weyl nodes, are significantly larger than in topological insulators. In thicker films, the Kerr and Faraday angles can be enhanced by choice of film thickness and substrate refractive index. We show that, for radiation incident on a surface with Fermi arcs, there is no Kerr or Faraday rotation but the electric field develops a longitudinal component inside the TWS, and there is linear dichroism signal. Our results have implications for probing the TWS phase in various experimental systems.

  6. Competing Turing and Faraday Instabilities in Longitudinally Modulated Passive Resonators.

    PubMed

    Copie, François; Conforti, Matteo; Kudlinski, Alexandre; Mussot, Arnaud; Trillo, Stefano

    2016-04-08

    We experimentally investigate the interplay of Turing (modulational) and Faraday (parametric) instabilities in a bistable passive nonlinear resonator. The Faraday branch is induced via parametric resonance owing to a periodic modulation of the resonator dispersion. We show that the bistable switching dynamics is dramatically affected by the competition between the two instability mechanisms, which dictates two completely novel scenarios. At low detunings from resonance, switching occurs between the stable stationary lower branch and the Faraday-unstable upper branch, whereas at high detunings we observe the crossover between the Turing and Faraday periodic structures. The results are well explained in terms of the universal Lugiato-Lefever model.

  7. Infrared spectroscopy of copper-resveratrol complexes: A joint experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Chiavarino, B.; Crestoni, M. E.; Fornarini, S.; Taioli, S.; Mancini, I.; Tosi, P.

    2012-07-01

    Infrared multiple-photon dissociation spectroscopy has been used to record vibrational spectra of charged copper-resveratrol complexes in the 3500-3700 cm-1 and 1100-1900 cm-1 regions. Minimum energy structures have been determined by density functional theory calculations using plane waves and pseudopotentials. In particular, the copper(I)-resveratrol complex presents a tetra-coordinated metal bound with two carbon atoms of the alkenyl moiety and two closest carbons of the adjoining resorcinol ring. For these geometries vibrational spectra have been calculated by using linear response theory. The good agreement between experimental and calculated IR spectra for the selected species confirms the overall reliability of the proposed geometries.

  8. Infrared spectroscopy of copper-resveratrol complexes: A joint experimental and theoretical study

    SciTech Connect

    Chiavarino, B.; Crestoni, M. E.; Fornarini, S.; Taioli, S.; Mancini, I.; Tosi, P.

    2012-07-14

    Infrared multiple-photon dissociation spectroscopy has been used to record vibrational spectra of charged copper-resveratrol complexes in the 3500-3700 cm{sup -1} and 1100-1900 cm{sup -1} regions. Minimum energy structures have been determined by density functional theory calculations using plane waves and pseudopotentials. In particular, the copper(I)-resveratrol complex presents a tetra-coordinated metal bound with two carbon atoms of the alkenyl moiety and two closest carbons of the adjoining resorcinol ring. For these geometries vibrational spectra have been calculated by using linear response theory. The good agreement between experimental and calculated IR spectra for the selected species confirms the overall reliability of the proposed geometries.

  9. Tank segmentation of infrared images with complex background for the homing anti-tank missile

    NASA Astrophysics Data System (ADS)

    Zhou, Yulong; Gao, Min; Fang, Dan; Zhang, Baoquan

    2016-07-01

    In an effort to achieve fast and effective tank segmentation of infrared images under complex background for the homing anti-tank missile, the threshold of the maximum between-class variance method (i.e., the Otsu method) is experimentally analyzed, and the working mechanism of the Otsu method is revealed. Subsequently, a fast and effective method for tank segmentation under complex background is proposed based on the Otsu method by constraining the image background pixels and gray levels. Firstly, with the prior information of the tank, derive the equation to calculate the number of pixels of tank according to optical imaging principle, and then use the calculated tank size to constrain the image background pixels. Secondly, employ the golden section to restrict the background gray levels. Finally, use the Otsu method to implement the segmentation of the tank. Experimental results demonstrate that the proposed method can get as an ideal result as the manual segmentation with less running time.

  10. Isotope effects in far-infrared spectra of bis(theophyllinato)copper(II)-complexes

    NASA Astrophysics Data System (ADS)

    Drożdżewski, Piotr; Kordon, Ewa

    1998-07-01

    Far-infrared spectra have been measured for 63Cu and 65Cu isotope substituted theophylline (Tp)-metal ion complexes: Cu(Tp) 2(NH 3) 2 · 2H 2O, Cu(Tp) 2(NH 3) 2, Cu(Tp) 2 · 2H 2O and Cu(Tp) 2. In addition, spectrum of Cu(Tp) 2(ND 3) 2 · 2D 2O has been recorded. Metal-theophylline, metal-ammine and water librational and translational modes have been assigned based on observed isotope shifts and complex dehydration effects. The copper-ammine vibrations have been found at 453 and 224 cm -1, whereas the bis(theophyllinato)copper(II) modes have been detected at 192 cm -1 for Cu(Tp) 2(NH 3) 2 and presumably at about 170 cm -1 for Cu(Tp) 2.

  11. Infrared spectra of van de Waals complexes of importance in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Fraser, G. T.; Pine, A. S.; Lafferty, W. J.

    1990-01-01

    It has been suggested that (CO2)2 and Ar-CO2 are important constituents of the planetary atmospheres of Venus and Mars. Recent results on the laboratory spectroscopy of CO2 containing van der Waals complexes which may be of use in the modeling of the spectra of planetary atmospheres are presented. Sub-Doppler infrared spectra were obtained for (CO2)2, (CO2)3, and rare-gas-CO2 complexes in the vicinity of the CO2 Fermi diad at 2.7 micrometers using a color-center-laser optothermal spectrometer. From the spectroscopic constants the geometries of the complexes have been determined and van der Waals vibrational frequencies have been estimated. The equilibrium configurations are C2h, C3h, and C2v, for (CO2)2, (CO2)3, and the rare-gas-CO2 complexes, respectively. Most of the homogeneous linewidths for the revibrational transitions range from 0.5 to 22 MHz, indicating that predissociation is as much as four orders of magnitude faster than radiative processes for vibrational relaxation in these complexes.

  12. Optimizing millisecond time scale near-infrared emission in polynuclear chrome(III)-lanthanide(III) complexes.

    PubMed

    Aboshyan-Sorgho, Lilit; Nozary, Homayoun; Aebischer, Annina; Bünzli, Jean-Claude G; Morgantini, Pierre-Yves; Kittilstved, Kevin R; Hauser, Andreas; Eliseeva, Svetlana V; Petoud, Stéphane; Piguet, Claude

    2012-08-01

    This work illustrates a simple approach for optimizing long-lived near-infrared lanthanide-centered luminescence using trivalent chromium chromophores as sensitizers. Reactions of the segmental ligand L2 with stoichiometric amounts of M(CF(3)SO(3))(2) (M = Cr, Zn) and Ln(CF(3)SO(3))(3) (Ln = Nd, Er, Yb) under aerobic conditions quantitatively yield the D(3)-symmetrical trinuclear [MLnM(L2)(3)](CF(3)SO(3))(n) complexes (M = Zn, n = 7; M = Cr, n = 9), in which the central lanthanide activator is sandwiched between the two transition metal cations. Visible or NIR irradiation of the peripheral Cr(III) chromophores in [CrLnCr(L2)(3)](9+) induces rate-limiting intramolecular intermetallic Cr→Ln energy transfer processes (Ln = Nd, Er, Yb), which eventually produces lanthanide-centered near-infrared (NIR) or IR emission with apparent lifetimes within the millisecond range. As compared to the parent dinuclear complexes [CrLn(L1)(3)](6+), the connection of a second strong-field [CrN(6)] sensitizer in [CrLnCr(L2)(3)](9+) significantly enhances the emission intensity without perturbing the kinetic regime. This work opens novel exciting photophysical perspectives via the buildup of non-negligible population densities for the long-lived doubly excited state [Cr*LnCr*(L2)(3)](9+) under reasonable pumping powers.

  13. Structural analysis and mapping of individual protein complexes by infrared nanospectroscopy

    NASA Astrophysics Data System (ADS)

    Amenabar, Iban; Poly, Simon; Nuansing, Wiwat; Hubrich, Elmar H.; Govyadinov, Alexander A.; Huth, Florian; Krutokhvostov, Roman; Zhang, Lianbing; Knez, Mato; Heberle, Joachim; Bittner, Alexander M.; Hillenbrand, Rainer

    2013-12-01

    Mid-infrared spectroscopy is a widely used tool for material identification and secondary structure analysis in chemistry, biology and biochemistry. However, the diffraction limit prevents nanoscale protein studies. Here we introduce mapping of protein structure with 30 nm lateral resolution and sensitivity to individual protein complexes by Fourier transform infrared nanospectroscopy (nano-FTIR). We present local broadband spectra of one virus, ferritin complexes, purple membranes and insulin aggregates, which can be interpreted in terms of their α-helical and/or β-sheet structure. Applying nano-FTIR for studying insulin fibrils—a model system widely used in neurodegenerative disease research—we find clear evidence that 3-nm-thin amyloid-like fibrils contain a large amount of α-helical structure. This reveals the surprisingly high level of protein organization in the fibril’s periphery, which might explain why fibrils associate. We envision a wide application potential of nano-FTIR, including cellular receptor in vitro mapping and analysis of proteins within quaternary structures.

  14. Lithologic analysis from multispectral thermal infrared data of the alkalic rock complex at Iron Hill, Colorado

    USGS Publications Warehouse

    Watson, K.; Rowan, L.C.; Bowers, T.L.; Anton-Pacheco, C.; Gumiel, P.; Miller, S.H.

    1996-01-01

    Airborne thermal-infrared multispectral scanner (TIMS) data of the Iron Hill carbonatite-alkalic igneous rock complex in south-central Colorado are analyzed using a new spectral emissivity ratio algorithm and confirmed by field examination using existing 1:24 000-scale geologic maps and petrographic studies. Color composite images show that the alkalic rocks could be clearly identified and that differences existed among alkalic rocks in several parts of the complex. An unsupervised classification algorithm defines four alkalic rock classes within the complex: biotitic pyroxenite, uncompahgrite, augitic pyroxenite, and fenite + nepheline syenite. Felsic rock classes defined in the surrounding country rock are an extensive class consisting of tuff, granite, and felsite, a less extensive class of granite and felsite, and quartzite. The general composition of the classes can be determined from comparisons of the TIMS spectra with laboratory spectra. Carbonatite rocks are not classified, and we attribute that to the fact that dolomite, the predominant carbonate mineral in the complex, has a spectral feature that falls between TIMS channels 5 and 6. Mineralogical variability in the fenitized granite contributed to the nonuniform pattern of the fenite-nepheline syenite class. The biotitic pyroxenite, which resulted from alteration of the pyroxenite, is spatially associated and appears to be related to narrow carbonatite dikes and sills. Results from a linear unmixing algorithm suggest that the detected spatial extent of the two mixed felsic rock classes was sensitive to the amount of vegetation cover. These results illustrate that spectral thermal infrared data can be processed to yield compositional information that can be a cost-effective tool to target mineral exploration, particularly in igneous terranes.

  15. Infrared spectrum and stability of the H2O-HO complex: experiment and theory.

    PubMed

    Soloveichik, Pesia; O'Donnell, Bridget A; Lester, Marsha I; Francisco, Joseph S; McCoy, Anne B

    2010-01-28

    Infrared action spectroscopy is utilized to characterize the gas-phase, hydrogen-bonded H(2)O-HO complex, a primary interaction in the hydration of the hydroxyl radical. The OH radical stretch of the H(2)O-HO complex is identified at 3490 cm(-1), shifted 78 cm(-1) to lower frequency of the OH monomer transition. The stability of the complex, D(0) < or = 5.14 kcal mol(-1), is derived from the highest observed OH product channel in the associated product state distribution. The assignment is supported by high level ab initio calculations of the spectral shift of the binary complex from free OH and its dissociation energy, D(e)(CBS-infinity) = 5.6 kcal mol(-1). A second weaker feature, appearing 15 cm(-1) to lower frequency at 3475 cm(-1), is attributed to a hot band, the OH radical stretch originating from an out-of-plane H(2)O bending state, based on two-dimensional calculations of frequencies and strengths of transitions involving the coupled vibrational modes.

  16. Theoretical study, and infrared and Raman spectra of copper(II) chelated complex with dibenzoylmethane.

    PubMed

    Nekoei, A-R; Vakili, M; Hakimi-Tabar, M; Tayyari, S F; Afzali, R; Kjaergaard, H G

    2014-07-15

    There are some discrepancies in both the vibrational assignments and in the metal-ligand (M-L) bond strengths predicted in the previous studies on the copper (II) chelated complex of dibenzoylmethane, Cu(dbm)2. Also, there is a lack of theoretical structure, Raman spectrum and full vibrational assignment for Cu(dbm)2 in the literatures. Density functional theory (DFT) at the B3LYP level and also MP2 calculations using different basis sets, besides Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) analyses, have been employed to investigate the effect of methyl substitution with the phenyl group on the stabilities of bis(acetylacetonate) copper (II), Cu(acac)2, and Cu(dbm)2 complexes and the electron delocalization in their chelated rings. Measured solid phase infrared and Raman bands for Cu(dbm)2 complex have been interpreted in terms of the calculated vibrational modes and detailed assignment has been presented. We concluded that, theoretically, the results of charge transfer studies, and experimentally, in-phase symmetric O-Cu-O stretching mode of these complexes are very useful measures for M-L bond strength. The electron delocalization in the chelated rings and the M-L bond strength in Cu(dbm)2 are concluded to be higher than those in Cu(acac)2. The calculated geometries and vibrational results are in good agreement with the experimental data. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Laser-Based Faraday-Effect Measurement of Magnetic Fluctuations and Fluctuation-Induced Transport

    NASA Astrophysics Data System (ADS)

    Lin, L.; Brower, D. L.; Ding, W. X.; Sarff, J. S.

    2013-10-01

    A multichord far-infrared laser-based Faraday-effect polarimetry diagnostic has been well developed on MST. Combined polarimetry-interferometry capability permits simultaneous measurement of internal structure of density and magnetic field with fast time response (~ 4 μs) and low phase noise (< 0 .01°) . With this diagnostic, the impact on toroidal current profile from a tangentially injected neutral beam is directly measured, allowing evaluation of non-inductive current drive. In addition, 0 .05° Faraday-effect fluctuations associated with global tearing modes are resolved with an uncertainty below 0 .01° . For physics investigations, these Faraday-effect fluctuations are complicated by contributions from both density and magnetic fluctuations. In our analysis, the local density fluctuations are obtained by inverting the line-integrated interferometry data after resolving the mode helicity through correlation techniques. The local magnetic fluctuations are then reconstructed using a parameterized fit of the polarimetry data, accounting for both the density and magnetic contributions. For the same mode, density and radial magnetic fluctuations exhibit very different spatial structure. In this process, their relative phase is also determined, thereby allowing the determination of magnetic-fluctuation-induced transport. Work supported by US DoE.

  18. Faraday-Effect Polarimeter-Interferometer System for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Haiqing; Jie, Yinxian; Ding, Weixing; Brower, David Lyn; Zou, Zhiyong; Qian, Jinping; Li, Weiming; Zeng, Long; Zhang, Shoubiao; Hu, Liqun; Wan, Baonian

    2015-11-01

    An eleven-channel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for current density and electron density profile measurements in the EAST tokamak. Both polarimetric and interferometric measurement are obtained in a long pulse (~ 52s) discharge. The electron line-integrated density resolution of POINT is less than 5 × 1016 m-2 (~ 2°), and the Faraday rotation angle rms phase noise is <0.1°. With the high temporal (~ 1 μsec) and phase resolution (<0.1°), density perturbations associated with the sawteeth cycle and tearing mode activities have been observed. It is evident that tearing modes are well correlated to dynamics of equilibrium current profile (or q-profile). Faraday rotation angle shows clear variation with low hybrid current drive while line-integrated density remains little changed, implying the current drive in the core. A Digital Phase Detector with 250 kHz bandwidth provides real-time Faraday rotation angle and density phase shift output, which will be integrated into current profile control system in a long pulse discharge in future. This work is supported by the National Magnetic Confinement Fusion Program of China with contract No. 2012GB101002 and partly supported by the US D.O.E. contract DESC0010469.

  19. Observation of Phillips's spectrum in Faraday waves

    NASA Astrophysics Data System (ADS)

    Castillo, Gustavo; Falcon, Claudio

    2016-11-01

    We consider the problem of wave turbulence generated by singularities from an experimental point of view. We study a system of Faraday waves interacting with waves generated by a wave-maker driven with a random forcing. We measure the temporal fluctuations of the surface wave amplitude at a given location and we show that for a wide range of forcing parameters the surface height displays a power-law spectra that greatly differs from the one predicted by the WT theory. In the capillary region the power spectrum turns out to be proportional to f-5, which we believe is due to singularities moving across the system. Proyecto Postdoctorado Fondecyt Nro 3160032.

  20. Structural determination of Zn and Cd-DTPA complexes: MS, infrared, (13)C NMR and theoretical investigation.

    PubMed

    Silva, Vanézia L; Carvalho, Ruy; Freitas, Matheus P; Tormena, Cláudio F; Melo, Walclée C

    2007-12-31

    The joint application of MS, infrared and (13)C NMR techniques for the determination of metal-DTPA structures (metal=Zn and Cd; DTPA=diethylenetriaminepentacetic acid) is reported. Mass spectrometry allowed determining the 1:1 stoichiometry of the complexes, while infrared analysis suggested that both nitrogen and carboxyl groups are sites for complexation. The (13)C NMR spectrum for the cadmium-containing complex evidenced the existence of free and complexed carboxyl groups, due to a straight singlet at 179.0 ppm (free carboxylic (13)C) and to two broad singlets or a broad doublet at 178.3 ppm (complexed carboxylic (13)C, (2)J(Cd-C(=O))=45.2 Hz). A similar interpretation might be given for the zinc derivative and, with the aid of DFT calculations, structures for both complexes were then proposed.

  1. Rethinking Faraday's Law for Teaching Motional Electromotive Force

    ERIC Educational Resources Information Center

    Zuza, Kristina; Guisasola, Jenaro; Michelini, Marisa; Santi, Lorenzo

    2012-01-01

    This study shows physicists' discussions on the meaning of Faraday's law where situations involving extended conductors or moving contact points are particularly troublesome. We raise questions to test students' difficulties in applying Faraday's law in motional electromotive force phenomena. We suggest the benefit of analysing these phenomena…

  2. Rethinking Faraday's Law for Teaching Motional Electromotive Force

    ERIC Educational Resources Information Center

    Zuza, Kristina; Guisasola, Jenaro; Michelini, Marisa; Santi, Lorenzo

    2012-01-01

    This study shows physicists' discussions on the meaning of Faraday's law where situations involving extended conductors or moving contact points are particularly troublesome. We raise questions to test students' difficulties in applying Faraday's law in motional electromotive force phenomena. We suggest the benefit of analysing these phenomena…

  3. A note on random excitation of nonlinear Faraday waves

    NASA Astrophysics Data System (ADS)

    Miles, John

    2004-06-01

    The evolution equations for weakly nonlinear Faraday waves in a cylinder that is subjected to a narrow-band, random acceleration are constructed and shown to be isomorphic to Repetto and Galletta's ["Finite amplitude Faraday waves induced by random forcing," Phys. Fluids 14, 4284 (2002)] results for the two-dimensional problem, which, therefore, are applicable to laboratory experiments in circular cylinders.

  4. Faraday isolator based on TSAG crystal for high power lasers.

    PubMed

    Mironov, E A; Palashov, O V

    2014-09-22

    A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.

  5. Patterns beyond Faraday waves: observation of parametric crossover from Faraday instabilities to the formation of vortex lattices in open dual fluid strata

    NASA Astrophysics Data System (ADS)

    Ohlin, Kjell; Berggren, Karl Fredrik

    2016-07-01

    Faraday first characterised the behaviour of a fluid in a container subjected to vertical periodic oscillations. His study pertaining to hydrodynamic instability, the ‘Faraday instability’, has catalysed a myriad of experimental, theoretical, and numerical studies shedding light on the mechanisms responsible for the transition of a system at rest to a new state of well-ordered vibrational patterns at fixed frequencies. Here we study dual strata in a shallow vessel containing distilled water and high-viscosity lubrication oil on top of it. At elevated driving power, beyond the Faraday instability, the top stratum is found to ‘freeze’ into a rigid pattern with maxima and minima. At the same time there is a dynamic crossover into a new state in the form of a lattice of recirculating vortices in the lower layer containing the water. Instrumentation and the physics behind are analysed in a phenomenological way together with a basic heuristic modelling of the wave field. The study, which is based on relatively low-budget equipment, stems from related art projects that have evolved over the years. The study is of value within basic research as well as in education, especially as more advanced collective project work in e.g. engineering physics, where it invites further studies of pattern formation, the emergence of vortex lattices and complexity.

  6. Investigation of the ionospheric Faraday rotation for use in orbit corrections

    NASA Technical Reports Server (NTRS)

    Llewellyn, S. K.; Bent, R. B.; Nesterczuk, G.

    1974-01-01

    The possibility of mapping the Faraday factors on a worldwide basis was examined as a simple method of representing the conversion factors for any possible user. However, this does not seem feasible. The complex relationship between the true magnetic coordinates and the geographic latitude, longitude, and azimuth angles eliminates the possibility of setting up some simple tables that would yield worldwide results of sufficient accuracy. Tabular results for specific stations can easily be produced or could be represented in graphic form.

  7. Application of infrared thermography in complex moisture inspection of the Schebek Palace

    NASA Astrophysics Data System (ADS)

    Balík, Lukáš; Kudrnáčová, Lucie; Pavlík, Zbyšek; Černý, Robert

    2017-07-01

    In situ moisture inspection of the basement floor of the Schebek Palace was done to get necessary information for intended repairs and adaptation of cellarage. At first, visual inspection of the basement was done to locate places for moisture content measurement. Within the experimental analysis, moisture distribution in several profiles of historical masonry was measured on a gravimetric principle. Herewith, non-destructive measurement of moisture content using a capacitive moisture meter was realised. The applied non-destructive technique made possible to minimize masonry and plaster damage due to the drilling of holes for samples extraction for gravimetric measurements. The capacitance method allowed also identification of wall moistening in larger areas. Since the moisture problems behind walls, over ceilings, and under floors is often impossible to detect until the problem is excessive and visible to the naked eye, infrared thermography was used to provide complex information on hygric state of analysed building. The obtained thermographs allowed to spot suspect areas of excessive moisture that were not apparent from visual control. Infrared camera was also useful in areas, where the moisture content had no clear relation to external moisture sources or did not correspond with capillary action from the subsoil. On the basis of experimental results, moisture sources of the masonry were identified and restoration treatments respecting the historical character of the inspected building were proposed.

  8. Searching for Faraday rotation in cosmic microwave background polarization

    NASA Astrophysics Data System (ADS)

    Ruiz-Granados, B.; Battaner, E.; Florido, E.

    2016-08-01

    We use the Wilkinson Microwave Anisotropy Probe (WMAP) 9th-year foreground reduced data at 33, 41 and 61 GHz to derive a Faraday rotation at map and at angular power spectrum levels taking into account their observational errors. A processing mask provided by WMAP is used to avoid contamination from the disc of our Galaxy and local spurs. We have found a Faraday rotation component at both, map and power spectrum levels. The lack of correlation of the Faraday rotation with Galactic Faraday rotation, synchrotron and dust polarization from our Galaxy or with cosmic microwave background anisotropies or lensing suggests that it could be originated at reionization (ℓ ≲ 12). Even if the detected Faraday rotation signal is weak, the present study could contribute to establish magnetic fields strengths of B0 ˜ 10-8 G at reionization.

  9. Infrared spectroscopy of dioxouranium(V) complexes with solvent molecules: effect of reduction.

    PubMed

    Groenewold, Gary S; Van Stipdonk, Michael J; de Jong, Wibe A; Oomens, Jos; Gresham, Garold L; McIlwain, Michael E; Gao, Da; Siboulet, Bertrand; Visscher, Lucas; Kullman, Michael; Polfer, Nick

    2008-06-23

    UO(2) (+)-solvent complexes having the general formula [UO(2)(ROH)](+) (R=H, CH(3), C(2)H(5), and n-C(3)H(7)) are formed using electrospray ionization and stored in a Fourier transform ion cyclotron resonance mass spectrometer, where they are isolated by mass-to-charge ratio, and then photofragmented using a free-electron laser scanning through the 10 mum region of the infrared spectrum. Asymmetric O=U=O stretching frequencies (nu(3)) are measured over a very small range [from approximately 953 cm(-1) for H(2)O to approximately 944 cm(-1) for n-propanol (n-PrOH)] for all four complexes, indicating that the nature of the alkyl group does not greatly affect the metal centre. The nu(3) values generally decrease with increasing nucleophilicity of the solvent, except for the methanol (MeOH)-containing complex, which has a measured nu(3) value equal to that of the n-PrOH-containing complex. The nu(3) frequency values for these U(V) complexes are about 20 cm(-1) lower than those measured for isoelectronic U(VI) ion-pair species containing analogous alkoxides. nu(3) values for the U(V) complexes are comparable to those for the anionic [UO(2)(NO(3))(3)](-) complex, and 40-70 cm(-1) lower than previously reported values for ligated uranyl(VI) dication complexes. The lower frequency is attributed to weakening of the O=U=O bonds by repulsion related to reduction of the U metal centre, which increases electron density in the antibonding pi* orbitals of the uranyl moiety. Computational modelling of the nu(3) frequencies using the B3LYP and PBE functionals is in good agreement with the IRMPD measurements, in that the calculated values fall in a very small range and are within a few cm(-1) of measurements. The values generated using the LDA functional are slightly higher and substantially overestimate the trends. Subtleties in the trend in nu(3) frequencies for the H(2)O-MeOH-EtOH-n-PrOH series are not reproduced by the calculations, specifically for the MeOH complex, which has a

  10. Femtosecond Time-Resolved Infrared Spectra of Organometallic Complexes Bound to a Dinuclear Metal Center

    NASA Astrophysics Data System (ADS)

    Brown-Xu, Samantha E.; Durr, Christopher B.

    2012-06-01

    Compounds of the form M2L2L'2, where M2 is a quadruply bonded metal center (M = Mo or W) and L and L' are conjugated organic ligands, are known to show interesting photophysical properties and exhibit intense metal-to-ligand charge transfer (MLCT) transitions throughout the visible spectrum. Recently, we have modified one of the ligands to incorporate a transition metal carbonyl complex bound to an organic moiety. Following excitation into the MLCT band, the vibrational modes of the organometallic ligand can be observed by fs time-resolved infrared (TRIR) spectroscopy. This allows for a visualization of where the electron density resides in the excited states, which provides useful information for designing new materials that could later be incorporated into solar devices.

  11. Infrared absorption on a complex comprising three equivalent hydrogen atoms in ZnO

    NASA Astrophysics Data System (ADS)

    Herklotz, F.; Hupfer, A.; Johansen, K. M.; Svensson, B. G.; Koch, S. G.; Lavrov, E. V.

    2015-10-01

    A hydrogen-related defect in ZnO which causes two broad IR absorption bands at 3303 and 3321 cm-1 is studied by means of infrared absorption spectroscopy and first-principles theory. In deuterated samples, the defect reveals two sharp absorption lines at 2466 and 2488 cm-1 accompanied by weaker sidebands at 2462 and 2480 cm-1. Isotope substitution experiments with varying concentrations of H and D together with polarization-sensitive measurements strongly suggest that these IR absorption lines are due to stretch local vibrational modes of a defect comprising three equivalent hydrogen atoms. The zinc vacancy decorated by three hydrogen atoms, VZnH3 , and ammonia trapped at the zinc vacancy, (NH3)Zn, are discussed as a possible origin for the complex.

  12. Two-dimensional infrared spectroscopy reveals the complex behaviour of an amyloid fibril inhibitor

    NASA Astrophysics Data System (ADS)

    Middleton, Chris T.; Marek, Peter; Cao, Ping; Chiu, Chi-Cheng; Singh, Sadanand; Woys, Ann Marie; de Pablo, Juan J.; Raleigh, Daniel P.; Zanni, Martin T.

    2012-05-01

    Amyloid formation has been implicated in the pathology of over 20 human diseases, but the rational design of amyloid inhibitors is hampered by a lack of structural information about amyloid-inhibitor complexes. We use isotope labelling and two-dimensional infrared spectroscopy to obtain a residue-specific structure for the complex of human amylin (the peptide responsible for islet amyloid formation in type 2 diabetes) with a known inhibitor (rat amylin). Based on its sequence, rat amylin should block formation of the C-terminal β-sheet, but at 8 h after mixing, rat amylin blocks the N-terminal β-sheet instead. At 24 h after mixing, rat amylin blocks neither β-sheet and forms its own β-sheet, most probably on the outside of the human fibrils. This is striking, because rat amylin is natively disordered and not previously known to form amyloid β-sheets. The results show that even seemingly intuitive inhibitors may function by unforeseen and complex structural processes.

  13. A high quantum yield molecule-protein complex fluorophore for near-infrared II imaging

    PubMed Central

    Antaris, Alexander L.; Chen, Hao; Diao, Shuo; Ma, Zhuoran; Zhang, Zhe; Zhu, Shoujun; Wang, Joy; Lozano, Alexander X.; Fan, Quli; Chew, Leila; Zhu, Mark; Cheng, Kai; Hong, Xuechuan; Dai, Hongjie; Cheng, Zhen

    2017-01-01

    Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with >1,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. Here, we report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with ∼50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. In addition, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body. PMID:28524850

  14. A high quantum yield molecule-protein complex fluorophore for near-infrared II imaging

    DOE PAGES

    Antaris, Alexander L.; Chen, Hao; Diao, Shuo; ...

    2017-05-19

    Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with 41,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. We report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for themore » fastest video-rate imaging in the second NIR window with B50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. Additionally, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body.« less

  15. The infrared spectrum of the He–C{sub 2}D{sub 2} complex

    SciTech Connect

    Moazzen-Ahmadi, N.; McKellar, A. R. W.; Fernández, Berta; Farrelly, David

    2015-02-28

    Spectra of the helium-acetylene complex are elusive because this weakly bound system lies close to the free rotor limit. Previously, limited assignments of He–C{sub 2}D{sub 2} transitions in the R(0) region of the ν{sub 3} fundamental band (≈2440 cm{sup −1}) were published. Here, new He–C{sub 2}D{sub 2} infrared spectra of this band are obtained using a tunable optical parametric oscillator laser source to probe a pulsed supersonic slit jet expansion from a cooled nozzle, and the analysis is extended to the weaker and more difficult P(1) and R(1) regions. A term value approach is used to obtain a consistent set of “experimental” energy levels. These are compared directly with calculations using two recently reported ab initio intermolecular potential energy surfaces, which exhibit small but significant differences. Rovibrational energies for the He–C{sub 2}H{sub 2} complex are also calculated using both surfaces. A Coriolis model, useful for predicting spectral intensities, is used to interpret the energy level patterns, and a comparison with the isoelectronic complex He–CO is made.

  16. A high quantum yield molecule-protein complex fluorophore for near-infrared II imaging

    NASA Astrophysics Data System (ADS)

    Antaris, Alexander L.; Chen, Hao; Diao, Shuo; Ma, Zhuoran; Zhang, Zhe; Zhu, Shoujun; Wang, Joy; Lozano, Alexander X.; Fan, Quli; Chew, Leila; Zhu, Mark; Cheng, Kai; Hong, Xuechuan; Dai, Hongjie; Cheng, Zhen

    2017-05-01

    Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with >1,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. Here, we report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with ~50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. In addition, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body.

  17. Infrared spectroscopy of Mg-CO2 and Al-CO2 complexes in helium nanodroplets.

    PubMed

    Thomas, Brandon J; Harruff-Miller, Barbara A; Bunker, Christopher E; Lewis, William K

    2015-05-07

    The catalytic reduction of CO2 to produce hydrocarbon fuels is a topic that has gained significant attention. Development of efficient catalysts is a key enabler to such approaches, and metal-based catalysts have shown promise towards this goal. The development of a fundamental understanding of the interactions between CO2 molecules and metal atoms is expected to offer insight into the chemistry that occurs at the active site of such catalysts. In the current study, we utilize helium droplet methods to assemble complexes composed of a CO2 molecule and a Mg or Al atom. High-resolution infrared (IR) spectroscopy and optically selected mass spectrometry are used to probe the structure and binding of the complexes, and the experimental observations are compared with theoretical results determined from ab initio calculations. In both the Mg-CO2 and Al-CO2 systems, two IR bands are obtained: one assigned to a linear isomer and the other assigned to a T-shaped isomer. In the case of the Mg-CO2 complexes, the vibrational frequencies and rotational constants associated with the two isomers are in good agreement with theoretical values. In the case of the Al-CO2 complexes, the vibrational frequencies agree with theoretical predictions; however, the bands from both structural isomers exhibit significant homogeneous broadening sufficient to completely obscure the rotational structure of the bands. The broadening is consistent with an upper state lifetime of 2.7 ps for the linear isomer and 1.8 ps for the T-shaped isomer. The short lifetime is tentatively attributed to a prompt photo-induced chemical reaction between the CO2 molecule and the Al atom comprising the complex.

  18. Analytical balance-based Faraday magnetometer

    NASA Astrophysics Data System (ADS)

    Riminucci, Alberto; Uhlarz, Marc; De Santis, Roberto; Herrmannsdörfer, Thomas

    2017-03-01

    We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1 mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3 × 10-8 A m2. We demonstrated its operation on magnetic composite scaffolds made of poly(ɛ-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24 mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials.

  19. Faraday Cup Detector Array with Electronic Interface

    NASA Astrophysics Data System (ADS)

    Scheidemann, Adi A.; Schumacher, Frank. J.; Darling, Robert B.; Isakharov, Arthur; Jones, Patrick

    2000-03-01

    A position sensitive Faraday cup detector array [FCDA] for ion beam detection has been developed. The FCDA is combined with an electronic multiplexing unit that allows collecting and integrating the charge deposited in the array and simultaneously reading out the same. The interface allows a duty cycle of > 98% for the position sensitive read-out, thus monitoring the entire array simultaneously. The multiplexing is achieved by collecting the charge with large number of small, and electronically de-coupled Faraday cups. The device measures absolute ion currents, has a wide dynamic range from 0.2 picoA to 2 microA, and a cross talk of less than 750:1. Read-out speeds ranging from 37 Hz to 117 kHz have been demonstrated. The low cross talk of the FCDA originates from an effective electronic de-coupling of the cups and a gray-code driven MUX-cascade as interface. The integration of the interface with the detector array on a printed circuit board allows further, reducing the number of feedthroughs that are necessary to monitor the array to six. Detector pitch sizes from 150 mm to 2.1mm haven been realized. A linear system composed of 256 elements and a square arrangement with 64 elements will be discussed.

  20. Computational simulation of Faraday probe measurements

    NASA Astrophysics Data System (ADS)

    Boerner, Jeremiah J.

    Electric propulsion devices, including ion thrusters and Hall thrusters, are becoming increasingly popular for long duration space missions. Ground-based experimental testing of such devices is performed in vacuum chambers, which develop an unavoidable background gas due to pumping limitations and facility leakage. Besides directly altering the operating environment, the background gas may indirectly affect the performance of immersed plasma probe diagnostics. This work focuses on computational modeling research conducted to evaluate the performance of a current-collecting Faraday probe. Initial findings from one dimensional analytical models of plasma sheaths are used as reference cases for subsequent modeling. A two dimensional, axisymmetric, hybrid electron fluid and Particle In Cell computational code is used for extensive simulation of the plasma flow around a representative Faraday probe geometry. The hybrid fluid PIC code is used to simulate a range of inflowing plasma conditions, from a simple ion beam consistent with one dimensional models to a multiple component plasma representative of a low-power Hall thruster plume. These simulations produce profiles of plasma properties and simulated current measurements at the probe surface. Interpretation of the simulation results leads to recommendations for probe design and experimental techniques. Significant contributions of this work include the development and use of two new non-neutral detailed electron fluid models and the recent incorporation of multi grid capabilities.

  1. Correcting ionospheric Faraday rotation for ASKAP

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Shane; Gaensler, Bryan; Landecker, Tom L.; Willis, Tony

    2012-10-01

    Next-generation polarisation surveys, such as the POSSUM survey on ASKAP, aim to measure weak, statistical, cosmological effects associated with weak magnetic fields, and so will require unprecedented accuracy and stability for measuring polarisation vectors and their Faraday rotation measures (RMs). Ionospheric Faraday rotation (IFR) corrupts polarization observations and cannot be ignored at mid to low frequencies. In aperture-synthesis polarimetry IFR rotates individual visibilities and leads to a loss of coherence and accuracy of polarization angle determination. Through the POSSUM survey science team we have been involved in developing detailed ionospheric prediction software (POSSUM memos #10a,b) that will be used to correct the observed visibilities on ASKAP before imaging to obtain sufficiently accurate polarization and RM data. To provide a stringent test of this software, we propose a continuous 24 hr observing block using the 1.1-3.1 GHz band to monitor the variations caused by the time-variable ionosphere in the polarization angle and RM of a strongly polarized calibrator source, PKS B1903-802. We request a total of 96 hrs (4 x 24 hrs) to monitor the changes in the ionosphere every 3 to 6 months until BETA/ASKAP-12 is taking reliable polarization data.

  2. Faraday diagnostics for R-damage

    SciTech Connect

    Oro, David M; Tabaka, Leonard J

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the R-Damage experiment.

  3. Micro-position sensor using faraday effect

    DOEpatents

    McElfresh, Michael; Lucas, Matthew; Silveira, Joseph P.; Groves, Scott E.

    2007-02-27

    A micro-position sensor and sensing system using the Faraday Effect. The sensor uses a permanent magnet to provide a magnetic field, and a magneto-optic material positioned in the magnetic field for rotating the plane of polarization of polarized light transmitted through the magneto-optic material. The magnet is independently movable relative to the magneto-optic material so as to rotate the plane of polarization of the polarized light as a function of the relative position of the magnet. In this manner, the position of the magnet relative to the magneto-optic material may be determined from the rotated polarized light. The sensing system also includes a light source, such as a laser or LED, for producing polarized light, and an optical fiber which is connected to the light source and to the magneto-optic material at a sensing end of the optical fiber. Processing electronics, such as a polarimeter, are also provided for determining the Faraday rotation of the plane of polarization of the back-reflected polarized light to determine the position of the magnet relative to the sensing end of the optical fiber.

  4. Midplane Faraday rotation: A tokamak densitometer

    NASA Astrophysics Data System (ADS)

    Jobes, F. C.

    1995-01-01

    The density in a tokamak can be determined by measuring the Faraday rotation of a laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then ne(R) can be readily obtained with a simple Abel inversion about the center line of the tokamak. For a large machine, such as ITER, TPX, or JT-60, a 10.6 μm laser would be appropriate. If the machine operated at a full field of 10-50 T m and a peak density of 2.5×1020/m3, the rotation angle would be quite large—about 15°-75° per pass. An elegant measurement system can be made up from a single laser beam diffracted off a moving grating to form a fan of ˜10 probe beams. With the addition of a few optical components to the system, the return beams can be recombined and sent to a single detector. In the detector there is a separate frequency component for both the right and left hand component of each ray. These can be separated electronically to provide a reference and probe signal for each ray; the difference in phase between the two signals is twice the Faraday rotation angle.

  5. X-Ray diffraction and Fourier transformation infrared spectroscopy studies of copper (II) thiourea chloro and sulphate complexes

    NASA Astrophysics Data System (ADS)

    Mishra, Ashutosh; Dwivedi, Jagrati; Shukla, Kritika; Malviya, Pramod

    2014-09-01

    Copper (II) thiourea complexes were synthesized by chemical route method. To analyze the samples, X-Ray diffraction and Fourier transformation infrared spectroscopy method have been used. XRD analysis shows that sample is crystalline in nature and having particle size in the range of nanometres. FTIR spectroscopy shows the organic and inorganic compounds present in the sample. The X-ray diffraction pattern (XRD) using Bruker D-8 advance instrument and Infrared spectra of the complexes were obtained by KBr disc technique by using VERTEX 70 (Bruker).

  6. High Resolution Infrared Spectroscopy of Propargyl Alcohol-Water Complex Embedded in Helium Nanodroplets

    NASA Astrophysics Data System (ADS)

    Mani, Devendra; Pal, Nitish; Kaufmann, Matin; Schwaab, Gerhard; Havenith, Martina

    2016-06-01

    Propargyl alcohol (hereafter abbreviated as PA) is a molecule of astrophysical interest and has been probed extensively using microwave spectroscopy.1,2 It is a multifunctional molecule and offers multiple sites for hydrogen bonding interactions. Therefore, it has also attracted the attention of groups interested in weak intermolecular interactions. Recently, the Ar…PA complex3 and PA-dimer4 have been studied using microwave spectroscopy. More recently, there have been matrix-isolation infrared spectroscopic studies on PA-water5 and PA-acetylene6 complexes. In the present work, clusters of PA and water were formed in the helium nanodroplets and probed using a combination of infrared spectroscopy and mass spectrometry. Using ab-initio quantum mechanical calculations, PA-water clusters were optimised and five minimum structures were found on the potential energy hypersurface, which were used as a guidance to the experiments. We used D2O for the experiments since our laser sources at Bochum do not cover the IR spectral region of H2O. IR spectra of PA-D2O complex were recorded in the region of symmetric and antisymmetric stretches of the bound D2O. Multiple signals were found in these regions which were dependent on the concentration of PA as well as D2O. Using pickup curves most of these signals could be assigned to 1:1 PA:D2O clusters. The ab-initio calculations helped in a definitive assignment of the spectra to the different conformers of PA-D2O complex. The details will be presented in the talk. References: 1. E. Hirota, J. Mol. Spec. 26, 335 (1968). 2. J.C. Pearson and B.J. Drouin, J. Mol. Spectrosc. 234, 149 (2005). 3. D. Mani and E. Arunan, ChemPhysChem 14, 754 (2013). 4. D. Mani and E. Arunan, J. Chem. Phys. 141, 164311 (2014). 5. J. Saini, K.S. Vishwanathan, J. Mol. Struct. 1118, 147 (2016). 6. K. Sundararajan et al., J. Mol. Struct. 1121, 26 (2016).

  7. Matrix infrared spectra and density functional calculations of transition metal hydrides and dihydrogen complexes.

    PubMed

    Andrews, Lester

    2004-02-20

    Metal hydrides are of considerable importance in chemical synthesis as intermediates in catalytic hydrogenation reactions. Transition metal atoms react with dihydrogen to produce metal dihydrides or dihydrogen complexes and these may be trapped in solid matrix samples for infrared spectroscopic study. The MH(2) or M(H(2)) molecules so formed react further to form higher MH(4), (H(2))MH(2), or M(H(2))(2), and MH(6), (H(2))(2)MH(2), or M(H(2))(3) hydrides or complexes depending on the metal. In this critical review these transition metal and dihydrogen reaction products are surveyed for Groups 3 though 12 and the contrasting behaviour in Groups 6 and 10 is discussed. Minimum energy structures and vibrational frequencies predicted by Density Functional Theory agree with the experimental results, strongly supporting the identification of novel binary transition metal hydride species, which the matrix-isolation method is well-suited to investigate. 104 references are cited.

  8. Infrared extinction spectra of mineral dust aerosol: Single components and complex mixtures

    NASA Astrophysics Data System (ADS)

    Laskina, Olga; Young, Mark A.; Kleiber, Paul D.; Grassian, Vicki H.

    2012-09-01

    Simultaneous Fourier transform infrared (FTIR) extinction spectra and aerosol size distributions have been measured for some components of mineral dust aerosol including feldspars (albite, oligoclase) and diatomaceous earth, as well as more complex authentic dust samples that include Iowa loess and Saharan sand. Spectral simulations for single-component samples, derived from Rayleigh-theory models for characteristic particle shapes, better reproduce the experimental spectra including the peak position and band shape compared to Mie theory. The mineralogy of the authentic dust samples was inferred using analysis of FTIR spectra. This approach allows for analysis of the mineralogy of complex multicomponent dust samples. Extinction spectra for the authentic dust samples were simulated from the derived sample mineralogy using published optical constant data for the individual mineral constituents and assuming an external mixture. Nonspherical particle shape effects were also included in the simulations and were shown to have a significant effect on the results. The results show that the position of the peak and the shape of the band of the IR characteristic features in the 800 to 1400 cm-1 spectral range are not well simulated by Mie theory. The resonance peaks are consistently shifted by more than +40 cm-1 relative to the experimental spectrum in the Mie simulation. Rayleigh model solutions for different particle shapes better predict the peak position and band shape of experimental spectra, even though the Rayleigh condition may not be strictly obeyed in these experiments.

  9. Isotope effects in the infrared spectra of OCS-He complexes and clusters.

    PubMed

    Abusara, Z; Borvayeh, L; Moazzen-Ahmadi, N; McKellar, A R W

    2006-10-14

    Infrared spectra of the OCS-He van der Waals complex and of OCS-He(N) clusters have been studied in the region of the OCS nu1 fundamental band using a tunable diode laser to probe a pulsed supersonic slit jet. For the complex, the spectrum of the normal isotope, 16O12C32S-4He, has been considerably extended and the 34S- and 13C-substituted forms have been recorded for the first time. The data could be analyzed satisfactorily using a conventional asymmetric rotor Hamiltonian with sextic centrifugal distortion terms. For the clusters, the 34S- and 13C-substituted forms have been observed and assigned for N = 2-7, including some transitions with higher J values than previously reported for the normal isotope, e.g., R5. The observed vibrational shifts, relative to the free OCS molecule, were very similar to those of the normal isotope, and most of the difference could be explained by simple scaling. These results constitute a subtle and precise probe of intermolecular forces and dynamical effects in a system which is of current interest for cluster studies.

  10. Mineralogy of S-complex Asteroids using Reflectance and Thermal Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lindsay, S. S.; Emery, J. P.; Marchis, F.; Enriquez, E.; Assafin, M.

    2013-12-01

    The S-type asteroids display an astounding diversity in mineralogy. They range from monomineralic olivine to complex olivine/pyroxene assemblages to basaltic assemblages. These materials are thought to be representative of an entire range of bodies that span essentially unmelted to bodies that experienced complete melting and igneous differentiation. Hence, the diverse silicate mineralogy for the S-type asteroids traces the thermal history of the asteroids a few Myr after formation. As such, determining the composition of S-type asteroids is a powerful investigative tool for understanding the post-accretionary thermal evolution, partial melting, and differentiation of the asteroids in the early Solar System. Moreover, the Sq and S(IV) are thought to be the parent bodies of ordinary chondrites (OCs), and therefore represent essentially unmelted or un-thermally processed materials. The mineralogy of these relatively unprocessed asteroids thus provide a window into investigating primitive Solar System materials, which were the building blocks of the terrestrial planets. The mineralogy of S-complex asteroids is typically determined using the 1- and 2-μm absorption bands related to olivine and pyroxene. Comparing the band centers, depths, and areas of these two features (i.e., band analysis) to calibrated laboratory data yields the general silicate mineralogy. Based on the near-infrared (NIR) band analysis, the S-type asteroids can be divided into seven subtypes, S(I - VII), with S(I)s being monomineralic olivine (mantle matieral), S(IV)s being analogous to OCs (primitive silicate material), and S(VII)s being basaltic material (igneously processed crustal material). The mid-infrared (MIR) thermal emission from asteroid surfaces exhibits a suite of silicate features due to Si-O stretching and O-Si-O bending vibrations near 10 and 18 μm, respectively. Marchis et al. (2012) demonstrated that the S-type asteroids exhibit diversity in their MIR emission. We seek to examine

  11. Development of a complex type of pour point-viscosity depressant and infrared spectrum research

    SciTech Connect

    Zhang Fusheng; Wang Biao

    1995-11-01

    EMS, a complex type of pour point-viscosity depressant for crudes, is composed of EVA, MVA [molecular structure shown for both in the paper] and Surfactant. After adding EMS into the crudes, a very nice result in reducing pour point and viscosity for Daqing, Jianghan and Jidong crudes was obtained. From the research result of infrared spectroscopy of the interactions between EMS or its components and wax or mixture of resin and asphaltene isolated from three crudes, it has been shown that the area ratio of the double absorption peaks of 719 cm{sup {minus}1} and 729 cm{sup {minus}1} or 1,368 cm{sup {minus}1} and 1,378 cm{sup {minus}1} changed remarkably after EMS or its components were added into wax. It can be inferred that the cocrystallization probably happened between the EMS or its components and the wax. The position of the 4,000--3,000 cm{sup {minus}1} infrared absorption peak of the mixture of resin and asphaltene moved to the lower wavenumber, and the ratio of the area of 1,373 cm{sup {minus}1} absorption peak (methyl) to the combination area of 748, 810 and 871 cm{sup {minus}1} absorption peak (aromatics) increased remarkably. It can be inferred that the pour point-viscosity depressant molecules destroyed the original hydrogen bonds and overlapping of the aromatic ring planes among resin and asphaltene molecules to form a new cubic molecular structure and new hydrogen bonds with the results the viscosity of crude oil will be reduced.

  12. Covalent and Noncovalent Interactions Between Boron and Argon: AN Infrared Photodissociation Spectroscopic Study of Argon-Boron Oxide Cation Complexes

    NASA Astrophysics Data System (ADS)

    Jin, Jiaye; Li, Wei; Wang, Guanjun; Zhou, Mingfei

    2017-06-01

    Although a wide range of compounds of the heavy rare-gas elements are experimentally known, very few chemically bound molecules have been experimentally observed for the lighter noble gases. Here we report a combined infrared photodissociation spectroscopic and theoretical study on a series of argon-boron oxide cation complexes prepared via a laser vaporization supersonic ion source in the gas phase. Infrared spectroscopic combined with state-of-the-art quantum chemical calculations indicate that the [ArB_3O_{4,5}]^+, [ArB_4O_{5-7}]^+ and [ArB_5O_7]^+ cation complexes have planar structures each involving an aromatic boroxol ring and an argon-boron covalent bond formed between the in-plane 2p atomic orbitals of Ar and boron. In contrast, the [ArB_3O_4]^+ cation complex is characterized to be a weakly bound complex with a BO chain structure.

  13. Infrared spectroscopic investigation of two isomers of the weakly bound complex OCS-(CO2)2.

    PubMed

    Oliaee, J Norooz; Mivehvar, F; Dehghany, M; Moazzen-Ahmadi, N

    2010-12-16

    Vibration-rotation spectra of the OCS-(CO(2))(2) van der Waals complex were studied by means of direct infrared absorption spectroscopy. Complexes were generated in a supersonic slit-jet apparatus, and the expansion gas was probed using a rapid-scan tunable diode laser. Infrared bands were observed for two different isomeric forms of the complex. A relatively strong band centered at 2058.799 cm(-1) was assigned to the most stable isomer, which has a barrel-shaped geometry and is already known from microwave spectroscopy. A weaker infrared band centered at 2050.702 cm(-1) was assigned to a new isomeric form, observed here for the first time, which was expected on the basis of ab initio calculations. Infrared bands for seven isotopomers were recorded in an attempt to quantify the structure of the new isomer. Because it has no symmetry elements, nine parameters are needed to fully define the geometry. It was possible to determine six of these which define the relative position of the OCS monomer with respect to the CO(2) dimer fragment in the complex while the remaining three were fixed at their ab initio values. Similarities and differences between the faces of the two isomers of OCS-(CO(2))(2) and the associated dimers are discussed.

  14. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  15. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  16. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy.

    PubMed

    Wagner, D R; Kim, H S; Saykally, R J

    2000-12-20

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  17. Infrared Multiphoton Dissociation of Duplex DNA/Drug Complexes in a Quadrupole Ion Trap

    PubMed Central

    Wilson, Jeffrey J.; Brodbelt, Jennifer S.

    2008-01-01

    Non-covalent duplex DNA/drug complexes formed between one of three 14-base pair non-self complementary duplexes with variable GC content and one of eight different DNA-interactive drugs are characterized by infrared multiphoton dissociation (IRMPD), and the resulting spectra are compared to conventional collisional activated dissociation (CAD) mass spectra in a quadrupole ion trap mass spectrometer. IRMPD yielded comparable information to previously reported CAD results in which strand separation pathways dominate for complexes containing the more AT-rich sequences and/or minor groove binding drugs, whereas drug ejection pathways are prominent for complexes containing intercalating drugs and/or duplexes with higher GC base content. The large photoabsorptive cross-section of the phosphate backbone at 10.6 μm promotes highly efficient dissociation within short irradiation times (< 2 ms at 50 W) or using lower laser powers and longer irradiation times (< 15 W at 15 ms), activation times on par with or shorter than standard CAD experiments. This large photoabsorptivity leads to a controllable ion activation method which can be used to produce qualitatively similar spectra to CAD while minimizing uninformative base loss dissociation pathways or instead be tuned to yield a high degree of secondary fragmentation. Additionally, the low mass cut-off associated with conventional CAD plays no role in IRMPD, resulting in richer MS/MS information in the low m/z region. IRMPD is also used for multi-adduct dissociation in order to increase MS/MS sensitivity, and a two stage IRMPD/IRMPD method is demonstrated as a means to give specific DNA sequence information that would be useful when screening drug binding by mixtures of duplexes. PMID:17249688

  18. Infrared Laser Stark Spectroscopy and AB Initio Computations of the OH\\cdotsCO Complex

    NASA Astrophysics Data System (ADS)

    Liang, Tao; Raston, Paul; Douberly, Gary

    2014-06-01

    Following the sequential pick-up of OH and CO by helium nanodroplets, the infrared depletion spectrum is measured in the fundamental OH stretching region. Although several potentially accessible minima exist on the associated OH + CO reactive potential energy surface [e.g. J. Ma, J. Li, and H. Guo, J. Phys. Chem. Lett. 3 (2012) 2482], such as the weakly bound OH-OC dimer and the chemically bound HOCO molecule, we only observe the weakly bound OH-CO dimer. The rovibrational spectrum of this complex displays narrow (0.02 cm-1) Lorentzian shaped peaks with spacings that are characteristic of a linear complex with unquenched electronic angular momentum, similar to what was previously observed in the gas phase [M.I. Lester, B.V. Pond, D.T. Anderson, L.B. Harding, and A.F. Wagner, J. Chem. Phys. 113 (2000) 9889]. Analogous spectra involving OD were collected, for which we also only observe the OD-CO isomer. From the Stark spectra, the dipole moments for OH-CO are determined to be 1.85(3) and 1.89(3) D for v=0 and v=1, respectively, while the analogous dipole moments for OD-CO are determined to be 1.88(8) and 1.94(5) D. The computed equilibrium ground state dipole moment at the CCSD(T)/Def2-TZVPD level of theory is 2.185 D, in disagreement with experiment. The role of vibrational averaging is investigated via the solution of a three-dimensional vibrational Schrödinger equation, which is constructed in internal bond-angle coordinates. The computed expectation value of the ground state dipole moment is in excellent agreement with experiment, indicating a floppy molecular complex.

  19. Faraday effect in Sn2P2S6 crystals.

    PubMed

    Krupych, Oleh; Adamenko, Dmytro; Mys, Oksana; Grabar, Aleksandr; Vlokh, Rostyslav

    2008-11-10

    We have revealed a large Faraday rotation in tin thiohypodiphosphate (Sn(2)P(2)S(6)) crystals, which makes this material promising for magneto-optics. The effective Faraday tensor component and the Verdet constant for the direction of the optic axis have been determined by measuring the pure Faraday rotation in Sn(2)P(2)S(6) crystals with both the single-ray and small-angular polarimetric methods at the normal conditions and a wavelength of 632.8 nm. The effective Verdet constant is found to be equal to 115 rad/T x m.

  20. Miniature modified Faraday cup for micro electron beams

    DOEpatents

    Teruya, Alan T.; Elmer, John W.; Palmer, Todd A.; Walton, Chris C.

    2008-05-27

    A micro beam Faraday cup assembly includes a refractory metal layer with an odd number of thin, radially positioned traces in this refractory metal layer. Some of the radially positioned traces are located at the edge of the micro modified Faraday cup body and some of the radially positioned traces are located in the central portion of the micro modified Faraday cup body. Each set of traces is connected to a separate data acquisition channel to form multiple independent diagnostic networks. The data obtained from the two diagnostic networks are combined and inputted into a computed tomography algorithm to reconstruct the beam shape, size, and power density distribution.

  1. The RSC Faraday prize lecture of 1989 on platinum.

    PubMed

    Thomas, John Meurig

    2017-08-25

    In 1861, Michael Faraday gave one of his last Friday Evening Discourses at the Royal Institution of Great Britain, London, on platinum, which he described as "this beautiful, magnificent and valuable metal". More than a hundred and twenty years later (in 1989), the author re-enacted, at the Royal Institution, many of the demonstrations that Faraday carried out in his memorable Discourse. This article outlines many of Faraday's views on, and experiments with, platinum. It also describes the continuing importance and utilization of platinum, both as perceived in 1989 and from present perspectives.

  2. Template analysis of a Faraday disk dynamo

    NASA Astrophysics Data System (ADS)

    Moroz, I. M.

    2008-12-01

    In a recent paper Moroz [1] returned to a nonlinear three-dimensional model of dynamo action for a self-exciting Faraday disk dynamo introduced by Hide et al. [2]. Since only two examples of chaotic behaviour were shown in [2], Moroz [1] performed a more extensive analysis of the dynamo model, producing a selection of bifurcation transition diagrams, including those encompassing the two examples of chaotic behaviour in [2]. Unstable periodic orbits were extracted and presented in [1], but no attempt was made to identify the underlying chaotic attractor. We rectify that here. Illustrating the procedure with one of the cases considered in [1], we use some of the unstable periodic orbits to identify a possible template for the chaotic attractor, using ideas from topology [3]. In particular, we investigate how the template is affected by changes in bifurcation parameter.

  3. Faraday instability of a spherical drop

    NASA Astrophysics Data System (ADS)

    Ebo Adou, A.; Tuckerman, Laurette; Shin, Seungwon; Chergui, Jalel; Juric, Damir

    2014-11-01

    A liquid drop subjected to an oscillatory radial force comprises a spherical version of the Faraday instability, with a subharmonic response which is half of the forcing frequency. The time-dependent shape of the drop and the velocity field in and around it are calculated using BLUE, a code based on a hybrid Front Tracking/Level-set algorithm for Lagrangian tracking of arbitrarily deformable phase interfaces. We compare this shape with the spherical harmonic selected at onset, calculated by adapting the Floquet stability analysis of Kumar and Tuckerman to a spherical geometry. We interpret the shape in light of theoretical results by Busse, Matthews and others concerning pattern formation in the presence of O(3) symmetry.

  4. Current measurement by Faraday effect on GEPOPU

    NASA Astrophysics Data System (ADS)

    N, Correa; H, Chuaqui; E, Wyndham; F, Veloso; J, Valenzuela; M, Favre; H, Bhuyan

    2014-05-01

    The design and calibration of an optical current sensor using BK7 glass is presented. The current sensor is based on the polarization rotation by Faraday effect. GEPOPU is a pulsed power generator, double transit time 120ns, 1.5 Ohm impedance, coaxial geometry, where Z pinch experiment are performed. The measurements were performed at the Optics and Plasma Physics Laboratory of Pontificia Universidad Catolica de Chile. The verdet constant for two different optical materials was obtained using He-Ne laser. The values obtained are within the experimental error bars of measurements published in the literature (less than 15% difference). Two different sensor geometries were tried. We present the preliminary results for one of the geometries. The values obtained for the current agree within the measurement error with those obtained by means of a Spice simulation of the generator. Signal traces obtained are completely noise free.

  5. Infrared spectra of the Li+-(H2)n (n=1-3) cation complexes

    NASA Astrophysics Data System (ADS)

    Emmeluth, C.; Poad, B. L. J.; Thompson, C. D.; Weddle, G. H.; Bieske, E. J.

    2007-05-01

    The Li+-(H2)n n =1-3 complexes are investigated through infrared spectra recorded in the H-H stretch region (3980-4120cm-1) and through ab initio calculations at the MP2/aug-cc-pVQZ level. The rotationally resolved H-H stretch band of Li+-H2 is centered at 4053.4cm-1 [a -108cm-1 shift from the Q1(0) transition of H2]. The spectrum exhibits rotational substructure consistent with the complex possessing a T-shaped equilibrium geometry, with the Li+ ion attached to a slightly perturbed H2 molecule. Around 100 rovibrational transitions belonging to parallel Ka=0-0, 1-1, 2-2, and 3-3 subbands are observed. The Ka=0-0 and 1-1 transitions are fitted by a Watson A-reduced Hamiltonian yielding effective molecular parameters. The vibrationally averaged intermolecular separation in the ground vibrational state is estimated as 2.056Å increasing by 0.004Å when the H2 subunit is vibrationally excited. The spectroscopic data are compared to results from rovibrational calculations using recent three dimensional Li+-H2 potential energy surfaces [Martinazzo et al., J. Chem. Phys. 119, 11241 (2003); Kraemer and Špirko, Chem. Phys. 330, 190 (2006)]. The H-H stretch band of Li+-(H2)2, which is centered at 4055.5cm-1 also exhibits resolved rovibrational structure. The spectroscopic data along with ab initio calculations support a H2-Li+-H2 geometry, in which the two H2 molecules are disposed on opposite sides of the central Li+ ion. The two equivalent Li+⋯H2 bonds have approximately the same length as the intermolecular bond in Li+-H2. The Li+-(H2)3 cluster is predicted to possess a trigonal structure in which a central Li+ ion is surrounded by three equivalent H2 molecules. Its infrared spectrum features a broad unresolved band centered at 4060cm-1.

  6. The complex evolutionary paths of local infrared bright galaxies: a high-angular resolution mid-infrared view

    NASA Astrophysics Data System (ADS)

    Alonso-Herrero, A.; Poulton, R.; Roche, P. F.; Hernán-Caballero, A.; Aretxaga, I.; Martínez-Paredes, M.; Ramos Almeida, C.; Pereira-Santaella, M.; Díaz-Santos, T.; Levenson, N. A.; Packham, C.; Colina, L.; Esquej, P.; González-Martín, O.; Ichikawa, K.; Imanishi, M.; Rodríguez Espinosa, J. M.; Telesco, C.

    2016-12-01

    We investigate the evolutionary connection between local infrared (IR)-bright galaxies (log LIR ≥ 11.4 L⊙) and quasars. We use high-angular resolution (˜0.3-0.4 arcsec ˜ few hundred parsecs) 8-13 μm ground-based spectroscopy to disentangle the active galactic nuclei (AGN) mid-IR properties from those of star formation. The comparison between the nuclear 11.3 μm polycyclic aromatic hydrocarbon feature emission and that measured with Spitzer/Spitzer Infrared Spectrograph indicates that the star formation is extended over a few kpc in the IR-bright galaxies. The AGN contribution to the total IR luminosity of IR-bright galaxies is lower than in quasars. Although the dust distribution is predicted to change as IR-bright galaxies evolve to IR-bright quasars and then to optical quasars, we show that the AGN mid-IR emission of all the quasars in our sample is not significantly different. In contrast, the nuclear emission of IR-bright galaxies with low AGN contributions appears more heavily embedded in dust although there is no clear trend with the interaction stage or projected nuclear separation. This suggests that the changes in the distribution of the nuclear obscuring material may be taking place rapidly and at different interaction stages washing out the evidence of an evolutionary path. When compared to normal AGN, the nuclear star formation activity of quasars appears to be dimming, whereas it is enhanced in some IR-bright nuclei, suggesting that the latter are in an earlier star formation-dominated phase.

  7. One-Piece Faraday Generator: A Paradoxical Experiment from 1851

    ERIC Educational Resources Information Center

    Crooks, M. J.; And Others

    1978-01-01

    Describes an experiment based on Faraday's one-piece generator, where the rotating disk is replaced by a cylindrical permanent magnet. Explains the apparent paradox that an observer in an inertial frame could measure his absolute velocity. (GA)

  8. Faraday effect based optical fiber current sensor for tokamaks

    SciTech Connect

    Aerssens, M.; Gusarov, A.; Brichard, B.; Massaut, V.; Megret, P.; Wuilpart, M.

    2011-07-01

    Fiber optical current sensor (FOCS) is a technique considered to be compatible with the ITER nuclear environment. FOCS principle is based on the magneto-optic Faraday effect that produces non-reciprocal circular birefringence when a magnetic field is applied in the propagation direction of the light beam. The magnetic field or the electrical current is deduced from the modification of the state of polarization of light. The linear birefringence of the fiber related with non-perfect manufacturing, temperature changes or stress constitute a parasitic effect that reduces the precision and sensitivity of FOCS. A two-pass optical scheme with a Faraday mirror at the end has been proposed to compensate the influence of linear birefringence. In this paper we perform a Stokes analysis of the two-pass optical scheme to highlight the fact that the linear birefringence is not compensated perfectly by the Faraday mirror when non-reciprocal birefringence such as Faraday effect is also present. (authors)

  9. Faraday effect in hybrid magneto-plasmonic photonic crystals.

    PubMed

    Caballero, B; García-Martín, A; Cuevas, J C

    2015-08-24

    We present a theoretical study of the Faraday effect in hybrid magneto-plasmonic crystals that consist of Au-Co-Au perforated membranes with a periodic array of sub-wavelength holes. We show that in these hybrid systems the interplay between the extraordinary optical transmission and the magneto-optical activity leads to a resonant enhancement of the Faraday rotation, as compared to purely ferromagnetic membranes. In particular, we determine the geometrical parameters for which this enhancement is optimized and show that the inclusion of a noble metal like Au dramatically increases the Faraday rotation over a broad bandwidth. Moreover, we show that the analysis of the Faraday rotation in these periodically perforated membranes provides a further insight into the origin of the extraordinary optical transmission.

  10. The Faraday effect of natural and artificial ferritins.

    PubMed

    Koralewski, M; Kłos, J W; Baranowski, M; Mitróová, Z; Kopčanský, P; Melníková, L; Okuda, M; Schwarzacher, W

    2012-09-07

    Measurements of the Faraday rotation at room temperature over the light wavelength range of 300-680 nm for horse spleen ferritin (HSF), magnetoferritin with different loading factors (LFs) and nanoscale magnetite and Fe(2)O(3) suspensions are reported. The Faraday rotation and the magnetization of the materials studied present similar magnetic field dependences and are characteristic of a superparamagnetic system. The dependence of the Faraday rotation on the magnetic field is described, excluding HSF and Fe(2)O(3), by a Langevin function with a log-normal distribution of the particle size allowing the core diameters of the substances studied to be calculated. It was found that the specific Verdet constant depends linearly on the LF. Differences in the Faraday rotation spectra and their magnetic field dependences allow discrimination between magnetoferritin with maghemite and magnetite cores which can be very useful in biomedicine.

  11. The Faraday effect of natural and artificial ferritins

    NASA Astrophysics Data System (ADS)

    Koralewski, M.; Kłos, J. W.; Baranowski, M.; Mitróová, Z.; Kopčanský, P.; Melníková, L.; Okuda, M.; Schwarzacher, W.

    2012-09-01

    Measurements of the Faraday rotation at room temperature over the light wavelength range of 300-680 nm for horse spleen ferritin (HSF), magnetoferritin with different loading factors (LFs) and nanoscale magnetite and Fe2O3 suspensions are reported. The Faraday rotation and the magnetization of the materials studied present similar magnetic field dependences and are characteristic of a superparamagnetic system. The dependence of the Faraday rotation on the magnetic field is described, excluding HSF and Fe2O3, by a Langevin function with a log-normal distribution of the particle size allowing the core diameters of the substances studied to be calculated. It was found that the specific Verdet constant depends linearly on the LF. Differences in the Faraday rotation spectra and their magnetic field dependences allow discrimination between magnetoferritin with maghemite and magnetite cores which can be very useful in biomedicine.

  12. Evaluation of Airborne Visible/Infrared Imaging Spectrometer Data of the Mountain Pass, California carbonatite complex

    NASA Technical Reports Server (NTRS)

    Crowley, James; Rowan, Lawrence; Podwysocki, Melvin; Meyer, David

    1988-01-01

    Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data of the Mountain Pass, California carbonatite complex were examined to evaluate the AVIRIS instrument performance and to explore alternative methods of data calibration. Although signal-to-noise estimates derived from the data indicated that the A, B, and C spectrometers generally met the original instrument design objectives, the S/N performance of the D spectrometer was below expectations. Signal-to-noise values of 20 to 1 or lower were typical of the D spectrometer and several detectors in the D spectrometer array were shown to have poor electronic stability. The AVIRIS data also exhibited periodic noise, and were occasionally subject to abrupt dark current offsets. Despite these limitations, a number of mineral absorption bands, including CO3, Al-OH, and unusual rare earth element bands, were observed for mine areas near the main carbonatite body. To discern these bands, two different calibration procedures were applied to remove atmospheric and solar components from the remote sensing data. The two procedures, referred to as the single spectrum and the flat field calibration methods gave distinctly different results. In principle, the single spectrum method should be more accurate; however, additional fieldwork is needed to rigorously determine the degree of calibration success.

  13. High-albedo C-complex outer-belt asteroids: The near-infrared spectra

    NASA Astrophysics Data System (ADS)

    Kasuga, T.; Usui, F.; Ootsubo, T.; Hasegawa, S.; Kuroda, D.; Shirahata, M.; Okamura, N.

    2014-07-01

    Primitive, outer-belt asteroids are generally of low albedo, reflecting carbonaceous compositions like those of CI and CM meteorites. However, a few outer-belt asteroids having high albedos are known, suggesting the presence of unusually reflective surface minerals or, conceivably, even exposed water ice. Here, we present near-infrared (1.1--2.5 micron) spectra of four outer-belt C-complex asteroids with albedos > 0.1. We find no absorption features characteristic of water ice (near 1.5 and 2.0 micron) in the objects. Intimate mixture models set limits to the water ice by weight < 2 %. Asteroids (723) Hammonia and (936) Kunigunde are featureless and have (60--95 %) amorphous Mg pyroxenes that might explain the high albedos. Asteroid (1276) Ucclia also shows a featureless reflection spectrum with (50--60 %) amorphous Mg pyroxenes. Asteroid (1576) Fabiola shows a possible weak, broad absorption band (1.5--2.1 micron). The feature can be reproduced by either (80 %) amorphous Mg pyroxenes or orthopyroxene (crystalline silicate), being likely to cause its high albedo. We discuss the origin of high-albedo components in primitive asteroids. This study is published in The Astronomical Journal, Volume 146, Issue 1, article id. 1, 6 pp. (2013).

  14. Unsupervised background-constrained tank segmentation of infrared images in complex background based on the Otsu method.

    PubMed

    Zhou, Yulong; Gao, Min; Fang, Dan; Zhang, Baoquan

    2016-01-01

    In an effort to implement fast and effective tank segmentation from infrared images in complex background, the threshold of the maximum between-class variance method (i.e., the Otsu method) is analyzed and the working mechanism of the Otsu method is discussed. Subsequently, a fast and effective method for tank segmentation from infrared images in complex background is proposed based on the Otsu method via constraining the complex background of the image. Considering the complexity of background, the original image is firstly divided into three classes of target region, middle background and lower background via maximizing the sum of their between-class variances. Then, the unsupervised background constraint is implemented based on the within-class variance of target region and hence the original image can be simplified. Finally, the Otsu method is applied to simplified image for threshold selection. Experimental results on a variety of tank infrared images (880 × 480 pixels) in complex background demonstrate that the proposed method enjoys better segmentation performance and even could be comparative with the manual segmentation in segmented results. In addition, its average running time is only 9.22 ms, implying the new method with good performance in real time processing.

  15. Infrared complex refractive index of astrophysical ices exposed to cosmic rays simulated in the laboratory

    NASA Astrophysics Data System (ADS)

    Rocha, W. R. M.; Pilling, S.; de Barros, A. L. F.; Andrade, D. P. P.; Rothard, H.; Boduch, P.

    2017-01-01

    In the dense and cold regions of the interstellar medium, molecules can be adsorbed on to dust grains to form ice mantles. Once formed, these can be processed by ionizing radiation coming from the stellar or interstellar medium, leading to the formation of several new molecules in the ice. Among the different types of ionizing radiation, cosmic rays play an important role in solid-phase chemistry because of the large amount of energy deposited in the ices. The physicochemical changes induced by the energetic processing of astrophysical ices are recorded in a intrinsic parameter of the matter called the complex refractive index. In this paper, for the first time, we present a catalogue containing 39 complex refractive indices (n, k) in the infrared from 5000 to 600 cm-1 (2.0-16.6 μm) for 13 different water-containing ices processed in the laboratory by cosmic ray analogues. The calculation was performed using the NKABS - an acronym of the determination of N and K from absorbance data - code,which employs the Lambert-Beer and Kramers-Kronig equations to calculate the values of n and k. The results are also available at the following web site: http://www1.univap.br/gaa/nkabs-database/data.htm. As a test case, H2O:NH3:CO2:CH4 ice was employed in a radiative transfer simulation of a protoplanetary disc to show that these data are indispensable to reproduce the spectrum of ices containing young stellar objects.

  16. Infrared Spectra of He-, Ne-, and Ar-C_2D_2 Complexes

    NASA Astrophysics Data System (ADS)

    Rezai, M.; Moazzen-Ahmadi, N.; McKellar, A. R. W.; Fernandez, Berta; Farrelly, David

    2012-06-01

    Remarkably, there are no previously published experimental spectra of the helium-acetylene van der Waals complex. Apparently, infrared spectra of He-C_2H_2 were recorded around 1990 in Roger Miller's lab, but a detailed rotational assignment was not possible even with the help of two extensive sets of theoretical predictions. Here, we study rare gas-C_2D_2 complexes in the νb{3} region (˜2439 wn) using a rapid-scan tuneable diode laser spectrometer to probe a pulsed supersonic slit-jet expansion. The He-C_2D_2 assignment problem is readily apparent: most of the absorption is piled-up in a very narrow region around 2440.85 wn, close to the R(0) line of the C_2D_2 monomer. This pile-up is a signature of very weak anisotropy in the helium-acetylene intermolecular potential, leading to almost free internal rotation of the C_2D_2. We are able to achieve a convincing rotational assignment with the help of theoretical energy level calculations based on the intermolecular potential surface of Munteanu and Fernández. So far the results are limited to He-C_2D_2 transitions which correlate with the monomer R(0) transition. Ne-C_2D_2 also shows a free-rotation pile-up of lines near R(0) which makes assignment tricky. In contrast, Ar-C_2D_2 exhibits more conventional behavior and a normal asymmetric rotor analysis is possible. [1] T. Slee, R.J. Le Roy, and C.E. Chuaqui, Mol. Phys. 77, 111 (1992); R. Moszynski, P.E.S. Wormer, and A. van der Avoird, J. Chem. Phys. 102, 8385 (1995). [2] R. Munteanu and B. Fernández, J. Chem. Phys. 123, 014309 (2005).

  17. Vibration immunity for a triangular Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Fisher, Norman E.; Jackson, David A.

    1996-10-01

    We demonstrate a common-mode rejection scheme for a bulk- optic triangular Faraday current sensor that can eliminate optical noise induced by fiber-link vibration. The noise floor before applying common rejection was about 30 dB for a 100A Faraday signal and transceiver vibration levels of approximately 30 g. This was reduced to about 60 dB for the same vibration levels. The sensor's exploitation of Ampere's circuital law is also demonstrated.

  18. Evaluation of the Faraday angle by numerical methods and comparison with the Tore Supra and JET polarimeter electronics

    SciTech Connect

    Brault, C.; Gil, C.; Spuig, P.; Boboc, A.; Collaboration: JET-EFDA Contributors

    2011-04-15

    On the Tore Supra tokamak, a far infrared polarimeter diagnostic has been routinely used for diagnosing the current density by measuring the Faraday rotation angle. A high precision of measurement is needed to correctly reconstruct the current profile. To reach this precision, electronics used to compute the phase and the amplitude of the detected signals must have a good resilience to the noise in the measurement. In this article, the analogue card's response to the noise coming from the detectors and their impact on the Faraday angle measurements are analyzed, and we present numerical methods to calculate the phase and the amplitude. These validations have been done using real signals acquired by Tore Supra and JET experiments. These methods have been developed to be used in real-time in the future numerical cards that will replace the Tore Supra present analogue ones.

  19. Evaluation of the Faraday angle by numerical methods and comparison with the Tore Supra and JET polarimeter electronics.

    PubMed

    Brault, C; Gil, C; Boboc, A; Spuig, P

    2011-04-01

    On the Tore Supra tokamak, a far infrared polarimeter diagnostic has been routinely used for diagnosing the current density by measuring the Faraday rotation angle. A high precision of measurement is needed to correctly reconstruct the current profile. To reach this precision, electronics used to compute the phase and the amplitude of the detected signals must have a good resilience to the noise in the measurement. In this article, the analogue card's response to the noise coming from the detectors and their impact on the Faraday angle measurements are analyzed, and we present numerical methods to calculate the phase and the amplitude. These validations have been done using real signals acquired by Tore Supra and JET experiments. These methods have been developed to be used in real-time in the future numerical cards that will replace the Tore Supra present analogue ones.

  20. Faraday rotation due to excitation of magnetoplasmons in graphene microribbons.

    PubMed

    Tymchenko, Mykhailo; Nikitin, Alexey Yu; Martín-Moreno, Luis

    2013-11-26

    A single graphene sheet, when subjected to a perpendicular static magnetic field, provides a Faraday rotation that, per atomic layer, greatly surpasses that of any other known material. In continuous graphene, Faraday rotation originates from the cyclotron resonance of massless carriers, which allows dynamical tuning through either external electrostatic or magneto-static setting. Furthermore, the rotation direction can be controlled by changing the sign of the carriers in graphene, which can be done by means of an external electric field. However, despite these tuning possibilities, the requirement of large magnetic fields hinders the application of the Faraday effect in real devices, especially for frequencies higher than a few terahertz. In this work we demonstrate that large Faraday rotation can be achieved in arrays of graphene microribbons, through the excitation of the magnetoplasmons of individual ribbons, at larger frequencies than those dictated by the cyclotron resonance. In this way, for a given magnetic field and chemical potential, structuring graphene periodically can produce large Faraday rotation at larger frequencies than what would occur in a continuous graphene sheet. Alternatively, at a given frequency, graphene ribbons produce large Faraday rotation at much smaller magnetic fields than in continuous graphene.

  1. Highly emitting near-infrared lanthanide "encapsulated sandwich" metallacrown complexes with excitation shifted toward lower energy.

    PubMed

    Trivedi, Evan R; Eliseeva, Svetlana V; Jankolovits, Joseph; Olmstead, Marilyn M; Petoud, Stéphane; Pecoraro, Vincent L

    2014-01-29

    Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+ [12-MC(Zn(II),quinHA)-4]2[24-MC(Zn(II),quinHA)-8] (Ln3+ [Zn(II)MC(quinHA)]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+ [Zn(II)MC(quinHA)] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLn(L) = 2.88(2)%, τobs = 150.7(2) μs; Nd3+, QLn(L) = 1.35(1)%, τobs = 4.11(3) μs; Er3+, QLn(L) = 3.60(6)·10–2%, τobs = 11.40(3) μs), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties.

  2. Visible-near-infrared luminescent lanthanide ternary complexes based on beta-diketonate using visible-light excitation.

    PubMed

    Sun, Lining; Qiu, Yannan; Liu, Tao; Feng, Jing; Deng, Wei; Shi, Liyi

    2015-11-01

    We used the synthesized dinaphthylmethane (Hdnm) ligand whose absorption extends to the visible-light wavelength, to prepare a family of ternary lanthanide complexes, named as [Ln(dnm)3 phen] (Ln = Sm, Nd, Yb, Er, Tm, Pr). The properties of these complexes were investigated by Fourier transform infrared (FT-IR) spectroscopy, diffuse reflectance (DR) spectroscopy, thermogravimetric analyses, and excitation and emission spectroscopy. Generally, excitation with visible light is much more advantageous than UV excitation. Importantly, upon excitation with visible light (401-460 nm), the complexes show characteristic visible (Sm(3+)) as well as near-infrared (Sm(3+), Nd(3+), Yb(3+), Er(3+), Tm(3+), Pr(3+)) luminescence of the corresponding lanthanide ions, attributed to the energy transfer from the ligands to the lanthanide ions, an antenna effect. Now, using these near-infrared luminescent lanthanide complexes, the luminescent spectral region from 800 to 1650 nm, can be covered completely, which is of particular interest for biomedical imaging applications, laser systems, and optical amplification applications.

  3. Fluctuation dynamos and their Faraday rotation signatures

    NASA Astrophysics Data System (ADS)

    Bhat, Pallavi; Subramanian, Kandaswamy

    2013-03-01

    Turbulence is ubiquitous in many astrophysical systems like galaxies, galaxy clusters and possibly even the filaments in the intergalactic medium. We study fluctuation dynamo action in turbulent systems focusing on one observational signature, the random Faraday rotation measure (RM) from radio emission of background sources seen through the intermittent magnetic field generated by such a dynamo. We simulate the fluctuation dynamo in periodic boxes up to resolutions of 5123, with varying fluid and magnetic Reynolds numbers, and measure the resulting random RMs. We show that even though the magnetic field generated is intermittent, it still allows for contributions to the RM to be significant. When the dynamo saturates, the rms value of RM is of the order of 40-50 per cent of the value expected in a model where fields of strength Brms uniformly fill cells of the largest turbulent eddy but are randomly oriented from one cell to another. This level of RM dispersion is obtained across different values of magnetic Reynolds number and Prandtl number explored. We also use the random RMs to probe the structure of the generated fields to distinguish the contribution from intense and diffuse field regions. We find that the strong field regions (say with B > 2Brms) contribute only of the order of 15-20 per cent to the RM. Thus, rare structures do not dominate the RM; rather, the general `sea' of volume filling fluctuating fields are the dominant contributors. We also show that the magnetic integral scale, Lint, which is directly related to the RM dispersion, increases in all the runs, as Lorentz forces become important to saturate the dynamo. It appears that due to the ordering effect of the Lorentz forces, Lint of the saturated field tends to a modest fraction, 1/2-1/3 of the integral scale of the velocity field, for all our runs. These results are then applied to discuss the Faraday rotation signatures of fluctuation dynamo generated fields in young galaxies, galaxy

  4. Testing Ionospheric Faraday Rotation Corrections in CASA

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Moellenbrock, George

    2015-04-01

    The Earth’s ionosphere introduces direction- and time-dependent effects over a range of physical and temporal scales and so is a major source for unmodeled phase offsets for low frequency radioastronomical observations. Ionospheric effects are often the limiting factor to making sensitive radioastronomical measurements to probe the solar corona or coronal mass ejections at low frequencies (< 5 GHz). It has become common practice to use global ionospheric models derived from the Global Positioning System (GPS) to provide a means of externally calibrating low frequency data. We have developed a new calibration algorithm in the Common Astronomy Software Applications (CASA) package. CASA, which was developed to meet the data post-processing needs of next generation telescopes such as the Karl G. Jansky Very Large Array (VLA), did not previously have the capability to mitigate ionospheric effects. This algorithm uses GPS-based global ionosphere maps to mitigate the first and second order ionospheric effects (dispersion delay and Faraday rotation, respectively). We investigated several data centers as potential sources for global ionospheric models and chose the International Global Navigation Satellite System Service data product because data from other sources are generally too sparse to use without additional interpolation schemes. This implementation of ionospheric corrections in CASA has been tested on several sets of VLA observations and all of them showed a significant reduction of the dispersion delay. In order to rigorously test CASA’s ability to mitigate ionospheric Faraday rotation, we made VLA full-polarization observations of the standard VLA phase calibrators J0359+5057 and J0423+4150 in August 2014, using L band (1 - 2 GHz), S band (2 - 4 GHz), and C band (4 - 6 GHz) frequencies in the D array configuration. The observations were 4 hours in duration, beginning near local sunrise. In this paper, we give a general description of how these corrections are

  5. In-frame and inter-frame information based infrared moving small target detection under complex cloud backgrounds

    NASA Astrophysics Data System (ADS)

    Wan, Minjie; Gu, Guohua; Cao, Ercong; Hu, Xiaobo; Qian, Weixian; Ren, Kan

    2016-05-01

    Infrared moving small target detection under complex cloud backgrounds is one of the key techniques of infrared search and track (IRST) systems. This paper proposes a novel method based on in-frame inter-frame information to detect infrared moving small targets accurately. For a single frame, in the spatial domain, a directional max-median filter is developed to make a pre-processing and a background suppression filtering template is utilized on the denoised image to highlight target. Then, targets in cloud regions and non-cloud regions are extracted by different thresholds according to a cloud discrimination method so that a spatial domain map (SDM) is acquired. In the frequency domain, we design an α-DoB band-pass filter to conduct coarse saliency detection and make an amplitude transformation with smoothing processing which is the so-called elaborate saliency detection. Furthermore, a frequency domain map (FDM) is acquired by an adaptive binary segmentation method. Lastly, candidate targets in single frame are extracted by a discrimination based on intensity and spatial distance criteria. For consecutive frames, a false alarm suppression is conducted on account of differences of motion features between moving target and false alarms to improve detection accuracy again. Large numbers of experiments demonstrate that the proposed method has satisfying detection effectiveness and robustness for infrared moving small target detection under complex cloud backgrounds.

  6. Infrared Spectrum of CO-O2, a 'new' Weakly-Bound Complex

    NASA Astrophysics Data System (ADS)

    McKellar, Bob; Barclay, A. J.; Michaelian, K. H.; Moazzen-Ahmadi, Nasser

    2016-06-01

    Only a few weakly-bound complexes containing the O2 molecule have been characterized by high-resolution spectroscopy, notably N2O-O2 [1] and HF-O2 [2]. This neglect is no doubt due in part to the complications added by the oxygen unpaired electron spin. Here we report an extensive infrared spectrum of CO-O2, as observed in the CO fundamental band region (˜2150 wn) using a tunable quantum cascade laser to probe a pulsed supersonic jet expansion. The derived energy level pattern consists of 'stacks' characterized by K, the projection of the total angular momentum on the intermolecular axis. Five such stacks are observed in the ground vibrational state, and ten in the excited state, v(CO) = 1. They are divided into two groups, with no observed transitions between groups, and we believe these groups correlate with the two lowest rotational states of O2, namely (N, J) = (1, 0) and (1, 2). In many ways, the spectrum and energy levels are similar to those of CO-N2 [3], and we use the same approach for analysis, simply fitting each stack with its own origin, B-value, and distortion constants. The rotational constant of the lowest stack in the ground state (with K = 0) implies an effective intermolecular separation of 3.82 Å, but this should be interpreted with caution since it ignores possible effects of electron spin. [1] H.-B. Qian, D. Seccombe, and B.J. Howard, J. Chem. Phys. 107, 7658 (1997). [2] W.M. Fawzy, C.M. Lovejoy, D.J. Nesbitt, and J.T. Hougen, J. Chem. Phys. 117, 693 (2002); S. Wu, G. Sedo, E.M. Grumstrup, and K.R. Leopold, J. Chem. Phys. 127, 204315 (2007). [3] M. Rezaei, K.H. Michaelian, N. Moazzen-Ahmadi, and A.R.W. McKellar, J. Phys. Chem. A 117, 13752 (2013), and references therein.

  7. A femtosecond visible/visible and visible/mid-infrared transient absorption study of the light harvesting complex II.

    PubMed

    Stahl, Andreas D; Di Donato, Mariangela; van Stokkum, Ivo; van Grondelle, Rienk; Groot, Marie Louise

    2009-12-16

    Light harvesting complex II (LHCII) is the most abundant protein in the thylakoid membrane of higher plants and green algae. LHCII acts to collect solar radiation, transferring this energy mainly toward photosystem II, with a smaller amount going to photosystem I; it is then converted into a chemical, storable form. We performed time-resolved femtosecond visible pump/mid-infrared probe and visible pump/visible probe absorption difference spectroscopy on purified LHCII to gain insight into the energy transfer in this complex occurring in the femto-picosecond time regime. We find that information derived from mid-infrared spectra, together with structural and modeling information, provides a unique visualization of the flow of energy via the bottleneck pigment chlorophyll a604.

  8. Far- and mid-infrared spectroscopic analysis of the substrate-induced structural dynamics of respiratory complex I.

    PubMed

    Hielscher, Ruth; Friedrich, Thorsten; Hellwig, Petra

    2011-01-17

    The catalytic activity of the respiratory NADH:ubiquinone oxidoreductase (complex I) is based on conformational reorganizations. Herein we probe the effect of substrates on the conformational flexibility of complex I by means of (1)H/(2)H exchange kinetics at the level of the amide proton in the mid-infrared spectral range (1700-1500 cm(-1)). Slow, medium, and fast exchanging domains are distinguished that reveal different accessibilities to the solvent. Whereas amide hydrogens undergo rapid exchange with the solvent in an open structure, hydrogens experience much slower exchange when they are involved in H-bonded structures or when they are sterically inaccessible for the solvent. The results indicate a structure that is more open in the presence of both NADH and quinon. Complementary information on the overall internal hydrogen bonding of the protein was probed in the far infrared (300-30 cm(-1)), a spectral range that includes a continuum mode of the hydrogen bonding signature.

  9. Complexes of molecular and ionic character in the same matrix layer: infrared studies of the sulfuric acid/ammonia system.

    PubMed

    Rozenberg, Mark; Loewenschuss, Aharon; Nielsen, Claus J

    2011-06-16

    The atmospherically important interaction products of sulfuric acid and ammonia molecules have been firstly observed by matrix isolation Fourier transform infrared spectroscopy (MIS-FTIR). Infrared spectra of solid argon matrix layers, in which both H(2)SO(4) and NH(3) molecules were entrapped as impurities, were analyzed for bands not seen in matrix layers containing either of the parent molecules alone. Results were interpreted on the basis of spectral changes, experimental conditions, and semiempirically scaled frequencies from the B3LYP/aug-cc-pVTZ and B3LYP/aug-cc-pVQZ calculations. Bands were assigned to complexes of the H(2)SO(4)·NH(3) and H(2)SO(4)·[NH(3)](2) general formulas. They differ significantly: the 1:1 H(2)SO(4)·NH(3) complex is a strongly hydrogen bonded complex, an analogue of the H(2)SO(4)·H(2)O complex, studied previously. For the 1:2 H(2)SO(4)·[NH(3)](2) complex, spectral results indicate an almost complete proton transfer forming a complex of essentially the two ionic moieties HSO(4)(-) and [H(3)N···H···NH(3)](+), an analogue of the [H(2)O···H···OH(2)](+) "Zundel ion". © 2011 American Chemical Society

  10. Linear diffusion into a Faraday cage.

    SciTech Connect

    Warne, Larry Kevin; Lin, Yau Tang; Merewether, Kimball O.; Chen, Kenneth C.

    2011-11-01

    Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.

  11. Resonant inverse Faraday effect in nanorings

    NASA Astrophysics Data System (ADS)

    Koshelev, K. L.; Kachorovskii, V. Yu.; Titov, M.

    2015-12-01

    A circularly polarized light can induce a dissipationless dc current in a quantum nanoring which is responsible for a resonant helicity-driven contribution to magnetic moment. This current is not suppressed by thermal averaging despite its quantum nature. We refer to this phenomenon as the quantum resonant inverse Faraday effect. For weak electromagnetic field, when the characteristic coupling energy is small compared to the energy level spacing, we predict narrow resonances in the circulating current and, consequently, in the magnetic moment of the ring. For strong fields, the resonances merge into a wide peak with a width determined by the spectral curvature. We further demonstrate that weak short-range disorder splits the resonances and induces additional particularly sharp and high resonant peaks in dc current and magnetization. In contrast, long-range disorder leads to a chaotic behavior of the system in the vicinity of the separatrix that divides the phase space of the system into regions with dynamically localized and delocalized states.

  12. Multifrequency control of Faraday wave patterns.

    PubMed

    Topaz, Chad M; Porter, Jeff; Silber, Mary

    2004-12-01

    We show how pattern formation in Faraday waves may be manipulated by varying the harmonic content of the periodic forcing function. Our approach relies on the crucial influence of resonant triad interactions coupling pairs of critical standing wave modes with damped, spatiotemporally resonant modes. Under the assumption of weak damping and forcing, we perform a symmetry-based analysis that reveals the damped modes most relevant for pattern selection, and how the strength of the corresponding triad interactions depends on the forcing frequencies, amplitudes, and phases. In many cases, the further assumption of Hamiltonian structure in the inviscid limit determines whether the given triad interaction has an enhancing or suppressing effect on related patterns. Surprisingly, even for forcing functions with arbitrarily many frequency components, there are at most five frequencies that affect each of the important triad interactions at leading order. The relative phases of those forcing components play a key role, sometimes making the difference between an enhancing and suppressing effect. In numerical examples, we examine the validity of our results for larger values of the damping and forcing. Finally, we apply our findings to one-dimensional periodic patterns obtained with impulsive forcing and to two-dimensional superlattice patterns and quasipatterns obtained with multifrequency forcing.

  13. Near-infrared Polarimetric Study of the N159/N160 Star-forming Complex in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Kim, Jaeyeong; Jeong, Woong-Seob; Pyo, Jeonghyun; Pak, Soojong; Park, Won-Kee; Kwon, Jungmi; Tamura, Motohide

    2017-03-01

    We present near-infrared polarimetric results for the N159/N160 star-forming complex in the Large Magellanic Cloud with SIRPOL, the polarimeter of the Infrared Survey Facility. We separated foreground sources using their visual extinction derived from near-infrared photometric data. The 45 young stellar candidates and 2 high-excitation blobs were matched with our sources, and 12 of them showed high polarization that did not originate from the interstellar dust. We made a polarimetric catalog of 252, 277, and 89 sources at the J, H, and K s bands, respectively. Based on the ratios of the polarization degree between these bands, we verify that the origin of these polarized sources is the dichroic extinction from the interstellar dust aligned by the magnetic field and that the ratios follow a power-law dependence of {P}λ ∼ {λ }-0.9. The linear polarization vectors projected onto the Hα image of the complex turned out to follow the local magnetic field structure. The vector map overlaid on dust and gas emissions shows the close correlation between the magnetic field structure and surrounding interstellar medium. We suggest that the derived magnetic field structure supports the sequential formation scenario of the complex.

  14. Faraday instability in a near-critical fluid under weightlessness.

    PubMed

    Gandikota, G; Chatain, D; Amiroudine, S; Lyubimova, T; Beysens, D

    2014-01-01

    Experiments on near-critical hydrogen have been conducted under magnetic compensation of gravity to investigate the Faraday instability that arises at the liquid-vapor interface under zero-gravity conditions. We investigated such instability in the absence of stabilizing gravity. Under such conditions, vibration orients the interface and can destabilize it. The experiments confirm the existence of Faraday waves and demonstrate a transition from a square to a line pattern close to the critical point. They also show a transition very close to the critical point from Faraday to periodic layering of the vapor-liquid interface perpendicular to vibration. It was seen that the Faraday wave instability is favored when the liquid-vapor density difference is large enough (fluid far from the critical point), whereas periodic layering predominates for small difference in the liquid and vapor densities (close to the critical point). It was observed for the Faraday wave instability that the wavelength of the instability decreases as one approaches the critical point. The experimental results demonstrate good agreement to the dispersion relation for zero gravity except for temperatures very close to the critical point where a transition from a square pattern to a line pattern is detected, similarly to what is observed under 1g conditions.

  15. Anomalous Faraday rotation in the ISM/ICM

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2016-10-01

    Faraday effect is a common and useful way to deduce cosmic magnetic fields in the interstellar and intracluster media (ISM and ICM). Faraday rotation is the result of magnetically-induced birefringence in a dielectric medium causing a linearly polarized wave to suffer a rotation of its polarization axis as it traverses such a medium. However, the standard λ2-law of the rotation angle may not hold in strongly turbulent plasmas. Electromagnetic high-frequency and/or small-scale fluctuations may lead to effective collisionality with the pitch-angle diffusion coefficient being an effective ``quasi-collision'' frequency. Recently, we showed that quasi-collisionality may radically alter radiative transport properties of plasmas, such as absorption, transmission and reflection and other effects, which can be very important in laboratory and astrophysical plasmas. Here we briefly discuss the quasi-collisional generalization of the classical Faraday effect, which is drastically modified and can even become negative. Furthermore, we explore the origin of the long-known anomaly of Faraday rotation in a famous Cygnus regions. We argue that the anomaly can be due to the anomalous Faraday rotation in a thin ``blanket'' of turbulent plasma at the front of an interstellar bubble/shock. Supported by KU CLAS and DOE Grant ID0000225143 (07/01/16).

  16. Faraday-Effect Polarimeter-Interferometer System for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Haiqing; Jie, Yinxian; Ding, Weixing; Brower, David Lyn; Zou, Zhiyong; Li, Weiming; Qian, Jinping; Yang, Yao; Zeng, Long; Lan, Ting; Li, Gongshun; Hu, Liqun; Wan, Baonian

    2014-10-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. System time response (~1 microsecond) and phase resolution (<0.1°) allows resolution of fast equilibrium changes associated with MHD events. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (~2°), and the Faraday rotation angle rms phase noise is <0.1°. Initial results of POINT system will be presented. This work is supported by the National Magnetic Confinement Fusion Program of China Contract No. 2012GB101002. This work is partly supported by the US D.O.E. Contract DESC0010469.

  17. Faraday effect improvement by Dy{sup 3+}-doping of terbium gallium garnet single crystal

    SciTech Connect

    Chen, Zhe Yang, Lei; Hang, Yin; Wang, Xiangyong

    2016-01-15

    Highly transparent Dy{sup 3+}-doped terbium gallium garnet (TGG) single crystal was grown by Czochralski (Cz) method. Phase composition of the crystal was tested by XRD measurements. The distribution coefficient of Dy{sup 3+} in the crystal was obtained. The optical and magneto-optical properties were analyzed in detail, and magnetic properties of the Dy{sup 3+}-TGG crystal were studied. The paramagnetic behavior is observed down to 10 K. The as-grown crystal exhibited high optical transmittance, particularly in the visible region. The Faraday rotation was investigated over visible and near-infrared regions (VIS–NIR) at room temperature. The Verdet constants increase at measured wavelengths and high thermal stability was found in Dy{sup 3+}-doped TGG, as compared to the properties of pure TGG, indicating that Dy{sup 3+}-doped crystals are preferable for magneto-active materials used in Faraday devices at VIS–NIR wavelengths. - Graphical abstract: Highly transparent Dy{sup 3+}-doped terbium gallium garnet (TGG) and pure TGG single crystals were grown by Czochralski method. The Dy{sup 3+}-doped TGG possesses 20–30% higher Verdet values in reference to TGG independently on wavelength.

  18. Infrared multiple photon dissociation spectroscopy of group I and group II metal complexes with Boc-hydroxylamine.

    PubMed

    Dain, Ryan P; Gresham, Gary; Groenewold, Gary S; Steill, Jeffrey D; Oomens, Jos; Van Stipdonk, Michael J

    2013-08-30

    Hydroxamates are essential growth factors for some microbes, acting primarily as siderophores that solubilize iron for transport into a cell. Here we determined the intrinsic structure of 1:1 complexes between Boc-protected hydroxylamine and group I ([M(L)](+)) and group II ([M(L-H)](+)) cations, where M and L are the cation and ligand, respectively, which are convenient models for the functional unit of hydroxamate siderphores. The relevant complex ions were generated by electrospray ionization (ESI) and isolated and stored in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Infrared spectra of the isolated complexes were collected by monitoring (infrared) photodissociation yield as a function of photon energy. Experimental spectra were then compared to those predicted by density functional theory (DFT) calculations. The infrared multiple photon dissociation (IRMPD) spectra collected are in good agreement with those predicted to be lowest-energy by DFT. The spectra for the group I complexes contain six resolved absorptions that can be attributed to amide I and II type and hydroxylamine N-OH vibrations. Similar absorptions are observed for the group II cation complexes, with shifts of the amide I and amide II vibrations due to the change in structure with deprotonation of the hydroxylamine group. IRMPD spectroscopy unequivocally shows that the intrinsic binding mode for the group I cations involves the O atoms of the amide carbonyl and hydroxylamine groups of Boc-hydroxylamine. A similar binding mode is preferred for the group II cations, except that in this case the metal ion is coordinated by the O atom of the deprotonated hydroxylamine group. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Laplace's equation and Faraday's lines of force

    SciTech Connect

    Narasimhan, T.N.

    2007-06-01

    Boundary-value problems involve two dependent variables: a potential function, and a stream function. They can be approached in two mutually independent ways. The first, introduced by Laplace, involves spatial gradients at a point. Inspired by Faraday, Maxwell introduced the other, visualizing the flow domain as a collection of flow tubes and isopotential surfaces. Boundary-value problems intrinsically entail coupled treatment (or, equivalently, optimization) of potential and stream functions Historically, potential theory avoided the cumbersome optimization task through ingenious techniques such as conformal mapping and Green's functions. Laplace's point-based approach, and Maxwell's global approach, each provides its own unique insights into boundary-value problems. Commonly, Laplace's equation is solved either algebraically, or with approximate numerical methods. Maxwell's geometry-based approach opens up novel possibilities of direct optimization, providing an independent logical basis for numerical models, rather than treating them as approximate solvers of the differential equation. Whereas points, gradients, and Darcy's law are central to posing problems on the basis of Laplace's approach, flow tubes, potential differences, and the mathematical form of Ohm's law are central to posing them in natural coordinates oriented along flow paths. Besides being of philosophical interest, optimization algorithms can provide advantages that complement the power of classical numerical models. In the spirit of Maxwell, who eloquently spoke for a balance between abstract mathematical symbolism and observable attributes of concrete objects, this paper is an examination of the central ideas of the two approaches, and a reflection on how Maxwell's integral visualization may be practically put to use in a world of digital computers.

  20. Plasmon resonance enhanced optical transmission and magneto-optical Faraday effects in nanohole arrays blocked by metal antenna

    NASA Astrophysics Data System (ADS)

    Lei, Chengxin; Tang, Zhixiong; Wang, Sihao; Li, Daoyong; Chen, Leyi; Tang, Shaolong; Du, Youwei

    2017-07-01

    The properties of the optical and magneto-optical effects of an improved plasmonic nanohole arrays blocked by gold mushroom caps are investigated by using the finite difference time domain (FDTD) method. It is most noteworthy that the strongly enhanced Faraday rotation along with high transmittance has been achieved simultaneously by optimizing the parameters of nanostructure in a broad spectrum spanning visible to near-infrared frequencies, which is very important in practical application for designing novel optical and magneto-optical devices. In our designed structure, we obtained two extraordinary optical transmission (EOT) resonant peaks along with enhanced Faraday rotation and two peaks of the figure of merit (FOM). By optimizing the geometrical parameters of the structure, we can obtain an almost 10-fold enhancement of Faraday rotation with a corresponding transmittance 50%, and the FOM of 0.752 at the same wavelength. As expected, the optical and magneto-optical effects sensitively depends on the geometrical parameters of our structure, which can be simply tailored by the height of pillar, the diameter of mushroom cap, and the period of the structure, and so on. The physical mechanism of these physical phenomena in the paper has been explained in detail. These research findings are of great theoretical significance in developing the novel magneto-optical devices in the future.

  1. Predicting the infrared transition intensities in the Ar-HF complex: the key role of the dipole moment surface accuracy.

    PubMed

    Jankowski, Piotr; Ziółkowski, Marcin

    2008-01-21

    The method proposed earlier for the generation of the full-dimensional energy surface for van der Waals complexes [P. Jankowski, J. Chem. Phys. 121, 1655 (2004)] is used to obtain a fulldimensional dipole moment surface for the atom-diatom complex in calculations based on the coupled-cluster with single, double, and noniterative triple excitation approach and the aug-cc-pVQZ basis sets. This surface has been employed to calculate transition intensities of the infrared spectra of Ar-HF. Special attention has been paid to study the problem of relative intensities of the different bands which have not been properly predicted within the long-range models of the dipole moment [A. E. Thornley and J. M. Hutson, J. Chem. Phys. 101, 5578 (1994)]. The intensities calculated with the present dipole moment surface agree very well with the experimental data, which indicate that the short-range interactions significantly affect the dipole moment surface and the calculated intensities. To investigate the role of the accuracy of the dipole moment surface on infrared transition intensities in atom-diatom complexes, four models of increasing complexity are studied. Their performance is shown to strongly depend on the region of the interaction energy surface probed by the initial and final states of the individual transitions.

  2. Versatile, high-sensitivity faraday cup array for ion implanters

    DOEpatents

    Musket, Ronald G.; Patterson, Robert G.

    2003-01-01

    An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10.sup.11 -10.sup.18 ions/cm.sup.2 to be extended to below 10.sup.6 ions/cm.sup.2. The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm.sup.2 and >750 cm.sup.2, and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

  3. Faraday tomography with LOFAR: new probe of the interstellar

    NASA Astrophysics Data System (ADS)

    Alves, M. I. R.; Jelić, V.; Ferrière, K.; Boulanger, F.

    2016-12-01

    Magnetic fields are a key constituent of the interstellar medium of our Galaxy. However, their exact role in the Galactic ecosystem is still poorly understood since we do not yet have a complete view of its structure in the Galaxy. This is about to change with the Faraday tomography technique, which allows us to derive the magnetic field in separate regions along the line of sight. We first describe the principle of Faraday tomography and illustrate the power of this novel technique with some of the latest results from the LOw Frequency ARray (LOFAR). We present preliminary results of our LOFAR project, aimed at investigating the origin of the filamentary-like structures revealed by Faraday tomography observations.

  4. Far-infrared Hall Effect in YBCO films

    NASA Astrophysics Data System (ADS)

    Grayson, M.; Rigal, L.; Cerne, J.; Schmadel, D. C.; Drew, H. D.; Kung, P.-J.

    2001-03-01

    In order to gain insight into the so-called "anomalous Hall effect" in Hi Tc superconductors(T.R. Chien, D.A. Brawner, Z.Z. Wang, and N.P. Ong, PRB 43, 6242(1991).) we explore Hall measurements at far-infrared (FIR) frequencies and study the temperature dependence. We separately measure the real and imaginary parts of the magneto-optical response of YBCO thin films to polarized FIR light (15-250 cm-1). The induced rotation of linearly polarized light tells us the real part of the Faraday angle, Re[θ_F(ω)], and the induced dichroism of circularly polarized light tells us Im[θ_F(ω)]. We can then deduce the complex Hall angle without resorting to Kramers-Kronig (K-K) analysis. Since both the Hall angle and the Faraday angle obey sum rules, we can compare to higher frequencies(Cerne, et al., invited talk) and determine additional information about the spectral response at intermediate frequencies. The consistency of these results is verified with K-K analysis.

  5. Evaluation of Plume Divergence and Facility Effects on Far-Field Faraday Probe Current Density Profiles

    DTIC Science & Technology

    2009-09-01

    elevated background pressure, compared nude Faraday probe designs, and evaluated design modifications to minimize uncertainty due to charge exchange...evaluated Faraday probe design and facility background pressure on collected ion current. A comparison of two nude Faraday probe designs concluded...140.5 Plasma potential in the region surrounding a nude Faraday probe has been measured to study the possibility of probe bias voltage acting as a

  6. Evaluation of ion collection area in Faraday probes.

    PubMed

    Brown, Daniel L; Gallimore, Alec D

    2010-06-01

    A Faraday probe with three concentric rings was designed and fabricated to assess the effect of gap width and collector diameter in a systematic study of the diagnostic ion collection area. The nested Faraday probe consisted of two concentric collector rings and an outer guard ring, which enabled simultaneous current density measurements on the inner and outer collectors. Two versions of the outer collector were fabricated to create gaps of 0.5 and 1.5 mm between the rings. Distribution of current density in the plume of a low-power Hall thruster ion source was measured in azimuthal sweeps at constant radius from 8 to 20 thruster diameters downstream of the exit plane with variation in facility background pressure. A new analytical technique is proposed to account for ions collected in the gap between the Faraday probe collector and guard ring. This method is shown to exhibit excellent agreement between all nested Faraday probe configurations, and to reduce the magnitude of integrated ion beam current to levels consistent with Hall thruster performance analyses. The technique is further studied by varying the guard ring bias potential with a fixed collector bias potential, thereby controlling ion collection in the gap. Results are in agreement with predictions based on the proposed analytical technique. The method is applied to a past study comparing the measured ion current density profiles of two Faraday probe designs. These findings provide new insight into the nature of ion collection in Faraday probe diagnostics, and lead to improved accuracy with a significant reduction in measurement uncertainty.

  7. An assessment of the lifetime of Faraday shield elements

    NASA Astrophysics Data System (ADS)

    Caughman, J. B. O., II; Ruzic, D. N.; Hoffman, D. J.; Langley, R. A.; Lewis, M. B.; Ryan, P. M.

    The interaction of plasma with RF fields from an ion cyclotron range of frequencies (ICRF) antenna has been studied to estimate the amount of Faraday shield erosion expected in normal ICRF heating operation. Plasma parameters and ion energies have been measured in the near field of an antenna and used in a model to estimate the erosion rate of the Faraday shield surface. Experiments were conducted on the RF Test Facility, a magnetic mirror device at Oak Ridge National Laboratory, using a single-strap resonant loop antenna with a two-tier Faraday shield. The outer tier, facing the plasma, was layered with graphite tiles. The antenna was operated at currents and voltages within 50 percent of those expected in tokamaks. The time-varying floating potential was measured with a capacitively coupled probe, and the time-averaged floating potential, electron temperature, and electron density were measured with a Langmuir probe. Ion energies were measured with a gridded energy analyzer located below the antenna, and samples of silicon were placed on the Faraday shield surface to estimate the incident ion energy. The capacitive probe measurements show that the RF floating potential follows the magnetic field pattern of the antenna, indicating that the electromagnetic fields are responsible for the potential formation. Plasma parameters and ion energies have been correlated with the antenna current and used in a computational model of the plasma sheath to predict the amount of erosion expected from the Faraday shield elements exposed to plasma. Predictions of light ion sputtering of candidate Faraday shield materials are presented.

  8. An assessment of the lifetime of Faraday shield elements

    SciTech Connect

    Caughman, J.B.O. II; Ruzic, D.N. ); Hoffman, D.J.; Langley, R.A.; Lewis, M.B.; Ryan, P.M. )

    1990-01-01

    The interaction of plasma with rf fields from an ion cyclotron range of frequencies (ICRF) antenna has been studied to estimate the amount of Faraday shield erosion expected in normal ICRF heating operation. Plasma parameters and ion energies have been measured in the near field of an antenna and used in a model to estimate the erosion rate of the Faraday shield surface. Experiments were conducted on the RF Test Facility, a magnetic mirror device at Oak Ridge National Laboratory, using a single-strap resonant loop antenna with a two-tier Faraday shield. The outer tier, facing the plasma, was layered with graphite tiles. The antenna was operated at currents and voltages within 50% of those expected in tokamaks. The time-varying floating potential was measured with a capacitively coupled probe, and the time-averaged floating potential, electron temperature, and electron density were measured with a Langmuir probe. Ion energies were measured with a gridded energy analyser located below the antenna, and samples of silicon were placed on the Faraday shield surface to estimate the incident ion energy. The capacitive probe measurements show that the rf floating potential follows the magnetic field pattern of the antenna, indicating that the electromagnetic fields are responsible for the potential formation. Plasma parameters and ion energies have been correlated with the antenna current and used in a computational model of the plasma sheath to predict the amount of erosion expected from the Faraday shield elements exposed to plasma. Predictions of light ion sputtering of candidate Faraday shield materials are presented.

  9. All-Fiber Optical Faraday Mirror Using 56-wt%-Terbium-Doped Fiber

    SciTech Connect

    Sun, L.; Jiang, S.; Marciante, J.R.

    2010-06-22

    An all-fiber optical Faraday mirror that consists of a fiber Faraday rotator and a fiber Bragg grating is demonstrated. The fiber Faraday rotator uses a 21-cm-long section of 56-wt%-terbium-doped silicate fiber. The polarization state of the reflected light is rotated 89 degrees +/- 2 degrees with a 16-dB polarization extinction ratio.

  10. NGC 6334 V revisited: The complex nature of the infrared nebula

    NASA Astrophysics Data System (ADS)

    Tapia, M.; Persi, P.; Roth, M.

    2017-07-01

    A comprehensive analysis is presented of the most recent infrared observations of the small, very young and enigmatic infrared nebula associated with NGC 6334-V. We re-analized images from the Spitzer/IRAC (3.6 a 8 μm), Herschel/SPIRE/PACS (70 a 500 μm), VISTA (1.2 a 2.2 μm), VLT/VISIR (11.3 a 18.7 μm) and HST/NICMOS (2.0 μm) archives. The very high spatial resolution from the latter two sets, combined with very recent sub-millimetre maps, allow us to suggest several possible star-formation scenarios that explain the observed infrared and radio properties of the region. Evidence is provided of the presence of a small population of low and medium-mass young stars embedded in the infrared reflection nebulosity NGC 6334 V that coexist with the nearby much younger Class 0 protostars.

  11. Compensation of thermally induced polarisation distortions in Faraday isolators

    SciTech Connect

    Khazanov, E A

    1999-01-31

    Two new Faraday isolator designs are proposed. They make it possible to compensate partly for the depolarisation of radiation which occurs in magneto-optical elements because of the photoelastic effect caused by heating associated with the absorption of laser radiation. Analytic and numerical comparisons of the new and traditional designs demonstrate a significant (by orders of magnitude) increase in the isolation ratio of the new isolators. The results obtained indicate that it should be possible to construct a Faraday isolator with the isolation ratio of 30 dB for laser radiation with an average power of several kilowatts. (laser applications and other topics in quantum electronics)

  12. Microscopic Faraday rotation measurement system using pulsed magnetic fields.

    PubMed

    Egami, Shigeki; Watarai, Hitoshi

    2009-09-01

    Microscopic Faraday rotation measurement system using a pulsed magnetic field has been constructed, which can be applied to micron sized diamagnetic and paramagnetic materials. A pulsed magnetic coil could generate a maximum magnetic flux density of about 12 T. The performance of the microscopic Faraday rotation apparatus was demonstrated by the measurement of the Verdet constant V of a polystyrene particle, after the calibration of the pulsed magnetic flux density using a glass plate as a standard material. Also, the magneto-optical rotation dispersion of some diamagnetic substances have been measured and analyzed with V=alambda(-2)+b. The values of a and b were compared to their magnetic susceptibilities.

  13. Fast Faraday fading of long range satellite signals.

    NASA Technical Reports Server (NTRS)

    Heron, M. L.

    1972-01-01

    20 MHz radio signals have been received during the day from satellite Beacon-B when it was below the optical horizon by using a bank of narrow filters to improve the signal to noise ratio. The Faraday fading rate becomes constant, under these conditions, at a level determined by the plasma frequency just below the F-layer peak. Variations in the Faraday fading rate reveal fluctuations in the electron density near the peak, while the rate of attaining the constant level depends on the shape of the electron density profile.

  14. Probing C-H⋯N interaction in acetylene-benzonitrile complex using matrix isolation infrared spectroscopy and DFT computations

    NASA Astrophysics Data System (ADS)

    Gopi, R.; Ramanathan, N.; Sundararajan, K.

    2017-04-01

    Hydrogen-bonded complexes of acetylene (C2H2) and the benzonitrile (C6H5CN) have been investigated using matrix isolation infrared spectroscopy and DFT computations. The structure of the complexes and the energies were computed at B3LYP and B3LYP+D3 levels of theory using 6-311++G (d, p) and aug-cc-pVDZ basis sets. DFT computations indicated two minima corresponding to the C-H⋯N (global) and C-H⋯π interactions (local) of 1:1 C2H2-C6H5CN complexes, where C2H2 is the proton donor in both complexes. Experimentally, the 1:1 C-H⋯N complex identified from the shifts in the C-H and Ctbnd N stretching modes corresponding to the C2H2 and C6H5CN sub-molecules in N2 and Ar matrices. Atoms in Molecules and Natural Bond Orbital analyses were performed to understand the nature of interaction and to unravel the reasons for red-shifting of the C-H stretching frequency in these complexes. Energy decomposition analysis was carried out to discern the various stabilizing and destabilizing components as a result of hydrogen bonding in the C2H2-C6H5CN complexes.

  15. Investigating vibrational relaxation in cyanide-bridged transition metal mixed-valence complexes using two-dimensional infrared and infrared pump-probe spectroscopies

    PubMed Central

    Slenkamp, Karla M.; Lynch, Michael S.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira

    2016-01-01

    Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5RuIIINCFeII(CN)5]− (FeRu) dissolved in D2O or formamide and [(NC)5FeIICNPtIV(NH3)4NCFeII(CN)5]4− (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as models for understanding the role high frequency vibrational modes play in metal-to-metal charge transfers over a bridging ligand. However, there is currently little information about vibrational relaxation and dephasing dynamics of the anharmonically coupled νCN modes in the electronic ground state of these complexes. IR pump-probe experiments reveal that the vibrational lifetimes of the νCN modes are ∼2 times faster when FeRu is dissolved in D2O versus formamide. They also reveal that the vibrational lifetimes of the νCN modes of FePtFe in D2O are almost four times as long as for FeRu in D2O. Combined with mode-specific relaxation dynamics measured from the 2D IR experiments, the IR pump-probe experiments also reveal that intramolecular vibrational relaxation is occurring in all three systems on ∼1 ps timescale. Center line slope dynamics, which have been shown to be a measure of the frequency-frequency correlation function, reveal that the radial, axial, and trans νCN modes exhibit a ∼3 ps timescale for frequency fluctuations. This timescale is attributed to the forming and breaking of hydrogen bonds between each mode and the solvent. The results presented here along with our previous work on FeRu and FePtFe reveal a picture of coupled anharmonic νCN modes where the spectral diffusion and vibrational relaxation dynamics depend on the spatial localization of the mode on the molecular complex and its specific interaction with the solvent. PMID:27158634

  16. Crystalline sulfur dioxide: Crystal field splittings, absolute band intensities and complex refractive indices derived from infrared spectra

    NASA Technical Reports Server (NTRS)

    Khanna, R. K.; Zhao, Guizhi

    1986-01-01

    The infrared absorption spectra of thin crystalline films of sulfur dioxide at 90 K are reported in the 2700 to 450/cm region. The observed multiplicity of the spectral features in the regions of fundamentals is attributed to factor group splittings of the modes in a biaxial crystal lattice and the naturally present minor S-34, S-36, and O-18 isotopic species. Complex refractive indices determined by an iterative Kramers-Kronig analysis of the extinction data, and absolute band strengths derived from them, are also reported in this region.

  17. CH stretching vibration of N-methylformamide as a sensitive probe of its complexation: infrared matrix isolation and computational study.

    PubMed

    Sałdyka, M; Mielke, Z; Mierzwicki, K; Coussan, S; Roubin, P

    2011-08-21

    The complexes between trans-N-methylformamide (t-NMF) and Ar, N(2), CO, H(2)O have been studied by infrared matrix isolation spectroscopy and/or ab initio calculations. The infrared spectra of NMF/Ne, NMF/Ar and NMF/N(2)(CO,H(2)O)/Ar matrices have been measured and the effect of the complexation on the perturbation of t-NMF frequencies was analyzed. The geometries of the complexes formed between t-NMF and Ar, N(2), CO and H(2)O were optimized in two steps at the MP2/6-311++G(2d,2p) level of theory. The four structures, found for every system at this level, were reoptimized on the CP-corrected potential energy surface; both normal and CP corrected harmonic frequencies and intensities were calculated. For every optimized structure the interaction energy was partitioned according to the SAPT scheme and the topological distribution of the charge density (AIM theory) was performed. The analysis of the experimental and theoretical results indicates that the t-NMF-N(2) and CO complexes present in the matrices are stabilized by very weak N-H···N and N-H···C hydrogen bonds in which the N-H group of t-NMF serves as a proton donor. In turn, the t-NMF-H(2)O complex present in the matrix is stabilized by O-H···O(C) hydrogen bonding in which the carbonyl group of t-NMF acts as a proton acceptor. Both, the theoretical and experimental results indicate that involvement of the NH group of t-NMF in formation of very weak hydrogen bonds with the N(2) or CO molecules leads to a clearly noticeable red shift of the CH stretching wavenumber whereas engagement of the CO group as a proton acceptor triggers a blue shift of this wavenumber.

  18. Earth-based observations of Faraday rotation in radio bursts from Jupiter

    NASA Technical Reports Server (NTRS)

    Phillips, J. A.; Ferree, Thomas C.; Wang, Joe

    1989-01-01

    New observations have been made of Faraday rotation in decameter-wavelength radio bursts from the planet Jupiter. Data obtained during six Io-B storms clearly indicate that an appreciable fraction of the observed Faraday rotation occurs in the Jovian magnetosphere. All of the Faraday rotation observed during a single Io-A storm can be accounted for by earth's ionosphere. Measurements of the Faraday effect in Io-B emissions indicate that the source is in Jupiter's northern magnetic hemisphere. Observations of the Faraday effect in Io-C emissions are proposed to determine its location as well.

  19. Research on infrared dim-point target detection and tracking under sea-sky-line complex background

    NASA Astrophysics Data System (ADS)

    Dong, Yu-xing; Li, Yan; Zhang, Hai-bo

    2011-08-01

    Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system, the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties .There are some traditional point target detection algorithms, such as adaptive background prediction detecting method. When background has dispersion-decreasing structure, the traditional target detection algorithms would be more useful. But when the background has large gray gradient, such as sea-sky-line, sea waves etc .The bigger false-alarm rate will be taken in these local area .It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature ,in our opinion , from the perspective of mathematics, the detection of dim-point targets in image is about singular function analysis .And from the perspective image processing analysis , the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection, its essence is a separation of target and background of different singularity characteristics .The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore, the purpose of the image preprocessing is to reduce the effects from noise, also to raise the SNR of image, and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics , the median filter is used to

  20. Synthesis and infrared and fluorescent spectra of rare earth complexes with a new amide ligand.

    PubMed

    Cui, Haixia; Chen, Jianmin; Zhou, Huidi; Lu, Yanhua

    2007-11-01

    Solid complexes of rare earth nitrates and picrates with a new amide ligand, 1,6-bis[(2'-benzylaminoformyl)phenoxyl]hexane (L) have been prepared. These complexes are characterized by elemental analysis, UV-vis spectra and IR spectra. The fluorescent and luminescent properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state are also investigated. Under the excitation of UV light, these complexes except Tb(III) picrate complex exhibit characteristic emission of europium and terbium ions. The influence of the counter anion on the fluorescent intensity is also discussed.

  1. Faraday, Dickens and Science Education in Victorian Britain

    ERIC Educational Resources Information Center

    Melville, Wayne; Allingham, Philip V.

    2011-01-01

    The achievements of Michael Faraday in the fields of electricity and electrochemistry have led some to describe him as the greatest experimental scientist in history. Charles Dickens was the creative genius behind some of the most memorable characters in literature. In this article, we share an historical account of how the collaboration of these…

  2. Faraday signature of magnetic helicity from reduced depolarization

    SciTech Connect

    Brandenburg, Axel; Stepanov, Rodion

    2014-05-10

    Using one-dimensional models, we show that a helical magnetic field with an appropriate sign of helicity can compensate the Faraday depolarization resulting from the superposition of Faraday-rotated polarization planes from a spatially extended source. For radio emission from a helical magnetic field, the polarization as a function of the square of the wavelength becomes asymmetric with respect to zero. Mathematically speaking, the resulting emission occurs then either at observable or at unobservable (imaginary) wavelengths. We demonstrate that rotation measure (RM) synthesis allows for the reconstruction of the underlying Faraday dispersion function in the former case, but not in the latter. The presence of positive magnetic helicity can thus be detected by observing positive RM in highly polarized regions in the sky and negative RM in weakly polarized regions. Conversely, negative magnetic helicity can be detected by observing negative RM in highly polarized regions and positive RM in weakly polarized regions. The simultaneous presence of two magnetic constituents with opposite signs of helicity is shown to possess signatures that can be quantified through polarization peaks at specific wavelengths and the gradient of the phase of the Faraday dispersion function. Similar polarization peaks can tentatively also be identified for the bi-helical magnetic fields that are generated self-consistently by a dynamo from helically forced turbulence, even though the magnetic energy spectrum is then continuous. Finally, we discuss the possibility of detecting magnetic fields with helical and non-helical properties in external galaxies using the Square Kilometre Array.

  3. Michael Faraday: Prince of lecturers in Victorian England

    NASA Astrophysics Data System (ADS)

    Lan, Boon Leong; Lim, Jeanette B. S.

    2001-01-01

    In this note, we focus on Faraday as a lecturer/teacher. We trace his development as a lecturer/teacher and highlight his approaches in popular-science lecturing and in teaching chemistry to military cadets. We appraise his success and conclude with an account of his poignant last lecture.

  4. Professor Henry, Mr. Faraday, and the Hunt for Electromagnetic Induction

    NASA Astrophysics Data System (ADS)

    Moyer, Albert E.

    1997-04-01

    On different sides of the Atlantic but about the same time, Michael Faraday and Joseph Henry announced success in a quest that had preoccupied the scientific community for a decade: coaxing electricity from magnetism. "Mutual induction," what Faraday and Henry had identified in the early 1830s, would turn out to be not only a foundational concept in the physics of electricity and magnetism but also the principle behind the technology of electrical transformers and generators--two mainstays of industrialization. Although Faraday's breakthrough in London and Henry's in Albany might appear to be classic examples of "independent discovery," they were not. The two natural philosophers shared a similar orientation toward their research and, moreover, a distinctive laboratory instrument: Henry's new, powerful electromagnet. Thus, the story of Henry's and Faraday's search for induction illuminates not only the workings of Victorian science but also the crucial part that an instrument--the unadorned hardware--can play in scientific inquiry. Albert Moyer takes this story from his biography of Joseph Henry that Smithsonian Institution Press is about to publish in commemoration of the 200th anniversary of Henry's birth. The biography focuses on Henry's early and middle years, 1797-1847, from his emergence as America's foremost physical scientist to his election as the Smithsonian Institution's first director.

  5. Theoretical model for a Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1991-01-01

    A model for the Faraday anomalous dispersion optical filter is presented. The model predicts a bandwidth of 0.6 GHz and a transmission peak of 0.98 for a filter operating on the Cs (D2) line. The model includes hyperfine effects and is valid for arbitrary magnetic fields.

  6. Concluding remarks: Faraday Discussion on chemistry in the urban atmosphere.

    PubMed

    Jimenez, Jose L

    2016-07-18

    This article summarises the Concluding remarks from the Faraday Discussion on Chemistry in the Urban Atmosphere. The following themes are addressed: (a) new results that inform our understanding of the evolving sources and composition of the urban atmosphere ("News"); (b) results that identify gaps in our understanding that necessitate further work ("Gaps");

  7. High-power Faraday isolators based on TAG ceramics.

    PubMed

    Zheleznov, Dmitry; Starobor, Aleksey; Palashov, Oleg; Chen, Chong; Zhou, Shengming

    2014-02-10

    The Faraday isolator based on a new magneto-optical medium--TAG (terbium aluminum garnet) ceramics was implemented and investigated experimentally. The magneto-optical element was temperature-stabilized using water cooling. The device provides a stable isolation ratio of 38 dB at 300 W laser power. Estimates show high performance of the device at a kilowatt laser power.

  8. Faraday's Investigation of Electromagnetic Induction. Experiment No. 21.

    ERIC Educational Resources Information Center

    Devons, Samuel

    This paper focuses on Michael Faraday's experimental research in electricity in the 1830's. Historical notes related to his work are included as well as experiments, his objectives, and illustrations of equipment for the experiments. Examples from his diary are given so that students can attempt to emulate his honest and systematic manner of…

  9. Faraday, Dickens and Science Education in Victorian Britain

    ERIC Educational Resources Information Center

    Melville, Wayne; Allingham, Philip V.

    2011-01-01

    The achievements of Michael Faraday in the fields of electricity and electrochemistry have led some to describe him as the greatest experimental scientist in history. Charles Dickens was the creative genius behind some of the most memorable characters in literature. In this article, we share an historical account of how the collaboration of these…

  10. Does a hydrogen bonded complex with dual contacts show synergism? A matrix isolation infrared and ab-initio study of propargyl alcohol-water complex

    NASA Astrophysics Data System (ADS)

    Saini, Jyoti; Viswanathan, K. S.

    2016-08-01

    When hydrogen bonded complexes are formed with more than one contact, the question arises if these multiple contacts operate synergistically. Propargyl alcohol-H2O complex presents a good case study to address this question, which is discussed in this work. Complexes of propargyl alcohol (PA) and H2O were studied experimentally using matrix isolation infrared spectroscopy, which was supported by quantum chemical computations performed at the M06-2X and MP2 level of theories, using 6-311++G (d,p) and aug-cc-pVDZ basis sets. A 1:1 PA-H2O complex was identified in the experiments and corroborated by our computations, where the PA was in the gauche conformation. This complex, which was a global minimum, showed dual interactions, one of which was an n-σ interaction between the O-H group of PA and the O of H2O, while the second was a H···​π contact between the O-H group of H2O and the π system of PA. We explored if the two interactions in the 1:1 complex exhibited synergism. We finally argue that the two interactions showed antagonism rather than synergism. Our computations indicated three other local minima for the 1:1 complexes; though these local minima were not identified in our experiments. Atoms-in-molecules and energy decomposition analysis executed through LMO-EDA were also performed to understand the nature of intermolecular interactions in the PA-H2O complexes. We have also revisited the problem of conformations of PA, with a view to understanding the reasons for gauche conformational preferences in PA.

  11. VLA Measurements of Faraday Rotation through Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Fischer, Patrick D.; Buffo, Jacob J.; Spangler, Steven R.

    2017-04-01

    Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the Sun, which play an important role in space weather. Faraday rotation is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME. Faraday rotation is proportional to the path integral through the plasma of the electron density and the line-of-sight component of the magnetic field. Faraday-rotation observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch. We report on simultaneous white-light and radio observations made of three CMEs in August 2012. We made sensitive Very Large Array (VLA) full-polarization observations using 1 - 2 GHz frequencies of a constellation of radio sources through the solar corona at heliocentric distances that ranged from 6 - 15 R_{⊙}. Two sources (0842+1835 and 0900+1832) were occulted by a single CME, and one source (0843+1547) was occulted by two CMEs. In addition to our radioastronomical observations, which represent one of the first active hunts for CME Faraday rotation since Bird et al. ( Solar Phys., 98, 341, 1985) and the first active hunt using the VLA, we obtained white-light coronagraph images from the Large Angle and Spectrometric Coronagraph (LASCO) C3 instrument to determine the Thomson-scattering brightness [BT], providing a means to independently estimate the plasma density and determine its contribution to the observed Faraday rotation. A constant-density force-free flux rope embedded in the background corona was used to model the effects of the CMEs on BT and Faraday rotation. The plasma densities (6 - 22×103 cm^{-3}) and axial magnetic-field strengths (2 - 12 mG) inferred from our models are consistent with the modeling work of Liu et al. ( Astrophys. J., 665, 1439, 2007) and Jensen and Russell ( Geophys. Res. Lett., 35, L02103, 2008), as well as previous CME Faraday-rotation observations by Bird et al

  12. Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

    NASA Astrophysics Data System (ADS)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2011-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

  13. A Study of Broadband Faraday Rotation and Polarization Behavior over 1.3--10 GHz in 36 Discrete Radio Sources

    NASA Astrophysics Data System (ADS)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.

    2016-07-01

    We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely sampled frequency band. Our sample was selected on the basis of polarization behavior apparent in narrowband archival data at 1.4 GHz: half the sample shows complicated frequency-dependent polarization behavior (i.e., Faraday complexity) at these frequencies, while half shows comparatively simple behavior (i.e., they appear Faraday simple). We re-observed the sample using the Australia Telescope Compact Array in full polarization, with 6 GHz of densely sampled frequency coverage spanning 1.3-10 GHz. We have devised a general polarization modeling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behavior in almost every source in our sample. Several sources exhibit particularly remarkable polarization behavior. By comparing our new and archival data, we have identified temporal variability in the broadband integrated polarization spectra of some sources. In a number of cases, the characteristics of the polarized emission components, including the range of Faraday depths over which they emit, their temporal variability, spectral index, and the linear extent of the source, allow us to argue that the spectropolarimetric data encode information about the magneto-ionic environment of active galactic nuclei themselves. Furthermore, the data place direct constraints on the geometry and magneto-ionic structure of this material. We discuss the consequences of restricted frequency bands on the detection and interpretation of polarization structures, and the implications for upcoming spectropolarimetric surveys.

  14. Zn(2+) and Cd(2+) cationized serine complexes: infrared multiple photon dissociation spectroscopy and density functional theory investigations.

    PubMed

    Coates, Rebecca A; Boles, Georgia C; McNary, Christopher P; Berden, Giel; Oomens, Jos; Armentrout, P B

    2016-08-10

    The gas-phase structures of zinc and cadmium dications bound to serine (Ser) are investigated by infrared multiple photon dissociation (IRMPD) action spectroscopy using the free electron laser FELIX, in combination with ab initio calculations. To identify the structures of the experimentally observed species, [Zn(Ser-H)CH3CN](+) and CdCl(+)(Ser), the measured action spectra are compared to linear absorption spectra calculated at the B3LYP/6-311+G(d,p) level for Zn(2+) containing complexes and B3LYP/def2-TZVP levels for Cd(2+) containing complexes. Good agreement between the observed IRMPD spectra and the predicted spectra allows identification of the isomers present. The intact amino acid interacting with cadmium chloride adopts a tridentate chelation involving the amino acid backbone amine and carbonyl groups as well as the hydroxyl group of the side-chain, [N,CO,OH]. The presence of two low-energy conformers is observed for the deprotonated serine-zinc complex, with the same tridentate coordination as for the cadmium complex but proton loss occurs at both the hydroxyl side-chain, [N,CO,O(-)], and the carboxylic acid of the amino acid backbone, [N,CO(-),OH]. These results are profitably compared with the analogous results previously obtained for comparable complexes with cysteine.

  15. Structure and photophysics of near-infrared emissive ytterbium(III) monoporphyrinate acetate complexes having neutral bidentate ligands.

    PubMed

    He, Hongshan; Sykes, Andrew G; May, P Stanley; He, Guishan

    2009-09-28

    Substitution reactions between [Yb(TPP)(OOCCH3)(CH3OH)2] (1) and neutral bidentate ligands NN led to the formation of monoporphyrinate ytterbium(III) complexes [Yb(TPP)(OOCCH3)(NN)] (TPP = 5,10,15,20-tetraphenylporphyrinate anion; NN = 4-methyl-1,10-phenanthroline (2), 1,10-phenanthroline (3), 4,7-dimethyl-1,10-phenanthroline (4), 5,6-epoxy-5,6-dihydroxy-1,10-phenanthroline (5) and 2,2'-dipyridylamine (6)). Single-crystal X-ray diffraction analysis revealed that ytterbium(III) ions in 1 and 6 were seven-coordinate with OOCCH3- in monodentate coordination, whereas those in 2, 3, 4 and 5 were eight-coordinate with OOCCH3- in bidentate coordination. The visible emission (650 and 720 nm) from the porphyrin and near-infrared (NIR) emission (980 and 1003 nm) from ytterbium(III) ion were observed for all complexes. The eight-coordinate complexes exhibited stronger NIR emission and longer lifetimes in toluene solution than the seven-coordinate complexes. The NIR emission of complexes with decreased lifetimes was also observed when they were blended into organic polymer PMMA.

  16. Infrared Spectroscopy of Gas-Phase M(+)(CO2)n (M = Co, Rh, Ir) Ion-Molecule Complexes.

    PubMed

    Iskra, Andreas; Gentleman, Alexander S; Kartouzian, Aras; Kent, Michael J; Sharp, Alastair P; Mackenzie, Stuart R

    2017-01-12

    The structures of gas-phase M(+)(CO2)n (M = Co, Rh, Ir; n = 2-15) ion-molecule complexes have been investigated using a combination of infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy and density functional theory. The results provide insight into fundamental metal ion-CO2 interactions, highlighting the trends with increasing ligand number and with different group 9 ions. Spectra have been recorded in the region of the CO2 asymmetric stretch around 2350 cm(-1) using the inert messenger technique and their interpretation has been aided by comparison with simulated infrared spectra of calculated low-energy isomeric structures. All vibrational bands in the smaller complexes are blue-shifted relative to the asymmetric stretch in free CO2, consistent with direct binding to the metal center dominated by charge-quadrupole interactions. For all three metal ions, a core [M(+)(CO2)2] structure is identified to which subsequent ligands are less strongly bound. No evidence is observed in this size regime for complete activation or insertion reactions.

  17. Complexation dynamics of CH3SCN and Li(+) in acetonitrile studied by two-dimensional infrared spectroscopy.

    PubMed

    Kwon, YoungAh; Park, Sungnam

    2015-10-07

    Ion-molecule complexation dynamics were studied with CH3SCN and Li(+) in acetonitrile by vibrationally probing the nitrile stretching vibration of CH3SCN. The nitrile stretching vibration of CH3SCN has a long lifetime (T1 = ∼90 ps) and its frequency is significantly blue-shifted when CH3SCN is bound with Li(+) ions to form a CH3SCNLi(+) complex in acetonitrile. Such spectral properties enable us to distinguish free CH3SCN and the CH3SCNLi(+) complex in solutions and measure their dynamics occurring on hundred picosecond timescales. For the complexation between CH3SCN and Li(+) in acetonitrile, the change in enthalpy (ΔH = -7.17 kJ mol(-1)) and the change in entropy (ΔS = -34.4 J K(-1) mol(-1)) were determined by temperature-dependent FTIR experiments. Polarization-controlled infrared pump-probe (IR PP) spectroscopy was used to measure the population decay and orientational dynamics of free CH3SCN and the CH3SCNLi(+) complex. Especially, the orientational relaxation of the CH3SCNLi(+) complex was found to be almost 3 times slower than those of free CH3SCN because Li(+) ions strongly interact with the neighboring solvents. Most importantly, the complexation dynamics of CH3SCN and Li(+) in acetonitrile were successfully measured in real time by 2DIR spectroscopy for the first time and the dissociation and association time constants were directly determined by using the two-species exchange kinetic model. Our experimental results provide a comprehensive overview of the ion-molecule complexation dynamics in solutions occurring under thermal equilibrium conditions.

  18. Sensitized electrophosphorescence of infrared emission diode based on copper phthalocyanine by an ytterbium complex

    NASA Astrophysics Data System (ADS)

    Yan, Fei; Li, Wen Lian; Chu, Bei; Li, Tian Le; Su, Wen Ming; Su, Zi Sheng; Zhu, Jian Zhuo; Yang, Dong Fang; Zhang, Guang; Bi, De Feng; Han, Liang Liang; Cheng, Chuan Hui; Fan, Zhao Qi; Yu, Shu Kun; Du, Guo Tong; Tsuboi, Taiju

    2007-11-01

    By inserting a layer of (dibenzoylmethanato)3-(bathophenanthroline)-ytterbium (Yb-C) between copper phthalocyanine (CuPc) emitting layer and electron transport layer, intense and broadband electroluminescence (EL) were achieved at 930-1300nm spectral region in a phosphorescent EL device. The intensity and bandwidth are increased by about 50 and 4 times, respectively, compared with the EL device without Yb-C layer. The improvement in the EL intensity and band broadening were attributed to the energy transfer from Yb-C to CuPc and the overlapping of the Yb3+ near-infrared emission band with the CuPc emission band.

  19. Infrared Spectroscopic Analysis of Linkage Isomerism in Metal-Thiocyanate Complexes

    ERIC Educational Resources Information Center

    Baer, Carl; Pike, Jay

    2010-01-01

    We developed an experiment suitable for an advanced inorganic chemistry laboratory that utilizes a cooperative learning environment, which allows students to develop an empirical method of determining the bonding mode of a series of unknown metal-thiocyanate complexes. Students synthesize the metal-thiocyanate complexes and obtain the FT-IR…

  20. Infrared Spectroscopic Analysis of Linkage Isomerism in Metal-Thiocyanate Complexes

    ERIC Educational Resources Information Center

    Baer, Carl; Pike, Jay

    2010-01-01

    We developed an experiment suitable for an advanced inorganic chemistry laboratory that utilizes a cooperative learning environment, which allows students to develop an empirical method of determining the bonding mode of a series of unknown metal-thiocyanate complexes. Students synthesize the metal-thiocyanate complexes and obtain the FT-IR…

  1. The infrared spectrum of the Ne-C2D2 complex.

    PubMed

    Moazzen-Ahmadi, N; McKellar, A R W; Fernández, Berta; Farrelly, David

    2015-11-28

    Infrared spectra of Ne-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm(-1)) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Like helium-acetylene, this system lies close to the free rotor limit, making analysis tricky because stronger transitions tend to pile up close to monomer (C2D2) rotation-vibration transitions. Assignments are aided by predicted rotational energies calculated from a published ab initio intermolecular potential energy surface. The analysis extends up to the j = 3←2 band, where j labels C2D2 rotation within the dimer, and is much more complete than the limited infrared assignments previously reported for Ne-C2H2 and Ne-C2HD. Two previous microwave transitions within the j = 1 state of Ne-C2D2 are reassigned. Coriolis model fits to the theoretical levels and to the spectrum are compared. Since the variations observed as a function of C2D2 vibrational excitation are comparable to those noted between theory and experiment, it is evident that more detailed testing of theory will require vibrational averaging over the acetylene intramolecular modes.

  2. Linear-dichroic infrared spectral analysis of Cu(I)?homocysteine complex

    NASA Astrophysics Data System (ADS)

    Ivanova, B. B.; Arnaudov, M. G.; Bontchev, P. R.

    2004-03-01

    The interaction between homocysteine (HCysSH) and Cu(II) leads to the formation of a yellow complex [Cu I(HCysS-SCysH) 2]Cl (1) after redox processes in the Cu(II)-homocysteine system resulting in dimerization of the ligand and formation of a mononuclear Cu(I) complex with two dimers. The structure of (1) was obtained by IR-LD spectral analysis of a solid amorphous sample oriented in nematic liquid crystal medium. The original technique for orientation developed here and the polarized IR spectra thus obtained, permit the determination of the complexation sites and coordination mode of diamagnetic complexes. In the complex (1), Cu(I) is coordinated through the two O atoms of one COO - group of each of the ligands and the metal ion coordination sphere represents a distorted tetrahedron.

  3. Far- and mid-infrared spectroscopy of complex organic matter of astrochemical interest: coal, heavy petroleum fractions and asphaltenes

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; García-Hernández, D. A.; Manchado, Arturo

    2013-03-01

    The coexistence of a large variety of molecular species (i.e. aromatic, cycloaliphatic and aliphatic) in several astrophysical environments suggests that unidentified infrared emission (UIE) occurs from small solid particles containing a mix of aromatic and aliphatic structures (e.g. coal, petroleum, etc.), renewing the astronomical interest on this type of materials. A series of heavy petroleum fractions namely `distillate aromatic extract', `Residual Aromatic Extract', heavy aromatic fraction (BQ-1) and asphaltenes derived from BQ-1 were used together with anthracite coal and bitumen as model compounds in matching the band pattern of the emission features of proto-planetary nebulae (PPNe). All the model materials were examined in the mid-infrared (2.5-16.66 μm) and for the first time in the far-infrared (16.66-200 μm), and the infrared bands were compared with the UIE from PPNe. The best match of the PPNe band pattern is offered by the BQ-1 heavy aromatic oil fraction and by its asphaltenes fraction. Particularly interesting is the ability of BQ-1 to match the band pattern of the aromatic-aliphatic C-H stretching bands of certain PPNe, a result which is not achieved neither by the coal model nor by the other petroleum fractions considered here. This study shows that a new interesting molecular model of the emission features of PPNe is asphaltene molecules which are composed by an aromatic core containing three to four condensed aromatic rings surrounded by cycloaliphatic (naphtenic) and aliphatic alkyl chains. Instead, the weakness of the model involving a mixture of polycyclic aromatic hydrocarbons (PAHs) for modelling the aromatic infrared emission bands (AIBs) is shown. The laboratory spectra of these complex organic compounds represent a unique data set of high value for the astronomical community, e.g. they may be compared with the Herschel Space Observatory spectra (˜51-220 μm) of several astrophysical environments such as (proto-) planetary nebulae, H

  4. The H2O-CH3F Complex: a Combined Microwave and Infrared Spectroscopic Study Supported by Structure Calculations

    NASA Astrophysics Data System (ADS)

    Gnanasekar, Sharon Priya; Goubet, Manuel; Arunan, Elangannan; Georges, Robert; Soulard, Pascale; Asselin, Pierre; Huet, T. R.; Pirali, Olivier

    2015-06-01

    The H2O-CH3F complex could have two geometries, one with a hydrogen bond and one with the newly proposed carbon bond. While in general carbon bonds are weaker than hydrogen bonds, this complex appears to have comparable energies for the two structures. Infrared (IR) and microwave (MW) spectroscopic measurements using, respectively, the Jet-AILES apparatus and the FTMW spectrometer at the PhLAM laboratory, have been carried out to determine the structure of this complex. The IR spectrum shows the formation of the CH3F- H2O hydrogen bonded complex and small red-shifts in OH frequency most probably due to (CH3F)m-(H2O)n clusters. Noticeably, addition of CH_3F in the mixture promotes the formation of small water clusters. Preliminary MW spectroscopic measurements indicate the formation of the hydrogen bonded complex. So far, we have no experimental evidence for the carbon bonded structure. However, calculations of the Ar-CH3F complex show three energetically equivalent structures: a T-shape, a "fluorine" bond and a carbon bond. The MW spectrum of the (Ar)n-CH3F complexes is currently under analysis. Mani, D; Arunan, E. Phys. Chem. Chem. Phys. 2013, 15, 14377. Cirtog, M; Asselin, P; Soulard, P; Tremblay, B; Madebene, B; Alikhani, M. E; Georges, R; Moudens, A; Goubet, M; Huet, T.R; Pirali, O; Roy, P. J. Phys. Chem. A. 2011, 115, 2523 Kassi, S; Petitprez, D; Wlodarczak, G. J. Mol. Struct. 2000, 517-518, 375

  5. Seaquake waves: Standing wave dynamics with Faraday excitation and radiative loss

    NASA Astrophysics Data System (ADS)

    Dolven, Eric Thomas

    When a body of deep water is subjected to vertical oscillations with frequency w0 , linear theory predicts that a standing wave field with frequency w=w02 forms on the surface. The wave number k*=w2g is determined by the deep water dispersion relation. These waves are called Faraday waves after Michael Faraday [16] who first documented them in 1831. Since then, much work has been done to try and understand them. However, all the existing results are for high frequency capillary waves subjected to viscous damping. What is observed is a variety of standing wave patterns that may be stabilized for various forcing strengths and viscosities. We analyze a system in which the dominant mechanism for energy dispersal is radiation rather than viscosity. We suggest this as a first approximation to the transient motions associated with earthquakes at sea and find that the results give insight into seaquake dynamics and the complex interactions involved with water wave formation. These assumptions introduce a number of challenges along with introducing interesting dynamics. In particular, phase dynamics arise that lead to remarkable quasi-stationary states that evolve on a slow time scale.

  6. High-Throughput, Protein-Targeted Biomolecular Detection Using Frequency-Domain Faraday Rotation Spectroscopy.

    PubMed

    Murdock, Richard J; Putnam, Shawn A; Das, Soumen; Gupta, Ankur; Chase, Elyse D Z; Seal, Sudipta

    2017-01-16

    A clinically relevant magneto-optical technique (fd-FRS, frequency-domain Faraday rotation spectroscopy) for characterizing proteins using antibody-functionalized magnetic nanoparticles (MNPs) is demonstrated. This technique distinguishes between the Faraday rotation of the solvent, iron oxide core, and functionalization layers of polyethylene glycol polymers (spacer) and model antibody-antigen complexes (anti-BSA/BSA, bovine serum albumin). A detection sensitivity of ≈10 pg mL(-1) and broad detection range of 10 pg mL(-1) ≲ cBSA ≲ 100 µg mL(-1) are observed. Combining this technique with predictive analyte binding models quantifies (within an order of magnitude) the number of active binding sites on functionalized MNPs. Comparative enzyme-linked immunosorbent assay (ELISA) studies are conducted, reproducing the manufacturer advertised BSA ELISA detection limits from 1 ng mL(-1) ≲ cBSA ≲ 500 ng mL(-1) . In addition to the increased sensitivity, broader detection range, and similar specificity, fd-FRS can be conducted in less than ≈30 min, compared to ≈4 h with ELISA. Thus, fd-FRS is shown to be a sensitive optical technique with potential to become an efficient diagnostic in the chemical and biomolecular sciences.

  7. Integrating seasonal optical and thermal infrared spectra to characterize urban impervious surfaces with extreme spectral complexity: a Shanghai case study

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yao, Xinfeng; Ji, Minhe

    2016-01-01

    Despite recent rapid advancement in remote sensing technology, accurate mapping of the urban landscape in China still faces a great challenge due to unusually high spectral complexity in many big cities. Much of this complication comes from severe spectral confusion of impervious surfaces with polluted water bodies and bright bare soils. This paper proposes a two-step land cover decomposition method, which combines optical and thermal spectra from different seasons to cope with the issue of urban spectral complexity. First, a linear spectral mixture analysis was employed to generate fraction images for three preliminary endmembers (high albedo, low albedo, and vegetation). Seasonal change analysis on land surface temperature induced from thermal infrared spectra and coarse component fractions obtained from the first step was then used to reduce the confusion between impervious surfaces and nonimpervious materials. This method was tested with two-date Landsat multispectral data in Shanghai, one of China's megacities. The results showed that the method was capable of consistently estimating impervious surfaces in highly complex urban environments with an accuracy of R2 greater than 0.70 and both root mean square error and mean average error less than 0.20 for all test sites. This strategy seemed very promising for landscape mapping of complex urban areas.

  8. [Measurement and analysis on complex refraction indices of pear pollen in infrared band].

    PubMed

    Li, Le; Hu, Yi-hua; Gu, You-lin; Chen, Wei; Zhao, Yi-zheng; Chen, Shan-jing

    2015-01-01

    Pollen is an important part of bioaerosols, and its complex refractive index is a crucial parameter for study on optical characteristics and detection, identification of bioaerosols. The reflection spectra of pear pollen within the 2. 5 - 15µm waveband were measured by squash method. Based on the measured data, the complex refractive index of pear pollen within the wave-band of 2. 5 to 15 µm was calculated by using Kramers-Kroning (K-K) relation, and calculation deviation about incident angle and different reflectivities at high and low frequencies.were analyzed. The results indicate that 18 degrees angle of incidence and different reflectivities at high and low frequencies have little effect on the results, and it is practicable to calculate the complex refractive index of pollen based on its reflection spectral data. The data of complex refractive index of pollen have some reference value for optical characteristics of pollen, detection and identification of bioaerosols.

  9. Theoretical infrared and terahertz spectra of an RDX/aluminum complex.

    PubMed

    Guadarrama-Pérez, Carlos; Martínez de La Hoz, Julibeth M; Balbuena, Perla B

    2010-02-18

    Density functional theory is employed to characterize the infrared and terahertz spectra of an explosive molecular species, RDX, deposited over an aluminum surface, modeled as a planar cluster of Al(16). Changes in the inter- and intramolecular vibrational modes are systematically analyzed starting from the isolated monomer, dimer, and tetramer and then considering the interactions of the monomer with an Al plate. The results are compared to available experimental information for RDX films on Al surfaces. It is found that the RDX molecule changes conformation because of the interaction with the model Al surface, becoming closer to an AAA conformation with the three NO(2) groups in nearly axial positions. The calculated spectra serve as an initial guideline to interpret the main peaks of previously reported RDX films on Al.

  10. The infrared spectrum of the Ar-C2D2 complex

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2016-10-01

    Infrared spectra of Ar-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm-1) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Transitions are assigned involving K = 0-2 in the ground vibrational state, and K = 0-4 in the excited state. The intermolecular bending combination band is also observed, giving a bending frequency of 4.798 cm-1. Despite this low bending frequency, the Ar-C2D2 spectrum qualitatively resembles that of a normal semi-rigid molecule, in contrast to He- and Ne-C2D2 which are much closer to the limit of free internal rotation.

  11. The research on infrared small-target detection technology under complex background

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Wang, Xin; Chen, Jilu; Huang, Zhijian

    2011-06-01

    In this paper, some basic principles and the implementing flow charts of a series of algorithms for target detecting are described. Then, according to actual needs and the comparison results of those algorithms, some of them are optimized in combination with the image pre-processing. On the foundation of above works, a moving target detecting and tracking software base on the OpenCV is developed by the software developing platform MFC. Three kinds of detecting algorithms are integrated in this software. These three detecting algorithms are Frame Difference method, Background Estimation method and Mixture Gaussian Modeling method. In order to explain the software clearly, the framework and the function are described in this paper. At last, the implementing processes and results are analyzed, and those algorithms for detecting targets are evaluated from the two aspects of subjective and objective. This paper is very significant in the application of the infrared target detecting technology.

  12. Research on infrared small-target tracking technology under complex background

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Wang, Xin; Chen, Jilu; Pan, Tao

    2012-10-01

    In this paper, some basic principles and the implementing flow charts of a series of algorithms for target tracking are described. On the foundation of above works, a moving target tracking software base on the OpenCV is developed by the software developing platform MFC. Three kinds of tracking algorithms are integrated in this software. These two tracking algorithms are Kalman Filter tracking method and Camshift tracking method. In order to explain the software clearly, the framework and the function are described in this paper. At last, the implementing processes and results are analyzed, and those algorithms for tracking targets are evaluated from the two aspects of subjective and objective. This paper is very significant in the application of the infrared target tracking technology.

  13. A complex multi-notch astronomical filter to suppress the bright infrared sky.

    PubMed

    Bland-Hawthorn, J; Ellis, S C; Leon-Saval, S G; Haynes, R; Roth, M M; Löhmannsröben, H-G; Horton, A J; Cuby, J-G; Birks, T A; Lawrence, J S; Gillingham, P; Ryder, S D; Trinh, C

    2011-12-06

    A long-standing and profound problem in astronomy is the difficulty in obtaining deep near-infrared observations due to the extreme brightness and variability of the night sky at these wavelengths. A solution to this problem is crucial if we are to obtain the deepest possible observations of the early Universe, as redshifted starlight from distant galaxies appears at these wavelengths. The atmospheric emission between 1,000 and 1,800 nm arises almost entirely from a forest of extremely bright, very narrow hydroxyl emission lines that varies on timescales of minutes. The astronomical community has long envisaged the prospect of selectively removing these lines, while retaining high throughput between them. Here we demonstrate such a filter for the first time, presenting results from the first on-sky tests. Its use on current 8 m telescopes and future 30 m telescopes will open up many new research avenues in the years to come.

  14. Improving analysis of infrared spectrum of van der Waals complex with theoretical calculation: Applied to Xe-N2O complex

    NASA Astrophysics Data System (ADS)

    Shi, Lipeng; Zhao, Aiqing; Wang, Hongli; Yang, Dapeng; Zheng, Rui

    2017-03-01

    A section of infrared spectrum for Xe-N2O has been recorded in the N2O monomer ν1 region, but just 5 rotational resolved lines cannot make an effective rovibrational analysis. To improve the analysis of our observed spectrum for Xe-N2O, a new method is developed based on the bound state calculations with three ab initio potential energy surfaces (PESs). The accuracy of this method is validated by the excellent agreement between theoretical and experimental results for 152 rovibrational transition frequencies with a root mean square deviation of 0.00075 cm-1 and spectroscopic parameters with the deviation less than 0.6 MHz in the N2O monomer ν3 region. The rotational constants for the excited state are derived with the values of A = 12716.1, B = 1075.2, C = 987.9 MHz in the ν1 region of N2O monomer. The band origin of the spectrum is determined to be 1284.8760 cm-1 with a red shift of 0.0273 cm-1 compared with that of N2O monomer in the ν1 region. The excellent agreement between experimental and theoretical results confirms that this new method is extremely helpful to make a rovibrational analysis for the infrared spectrum of van der Waals complex.

  15. Spectral-domain low-coherence interferometry for phase-sensitive measurement of Faraday rotation at multiple depths.

    PubMed

    Yeh, Yi-Jou; Black, Adam J; Akkin, Taner

    2013-10-10

    We describe a method for differential phase measurement of Faraday rotation from multiple depth locations simultaneously. A polarization-maintaining fiber-based spectral-domain interferometer that utilizes a low-coherent light source and a single camera is developed. Light decorrelated by the orthogonal channels of the fiber is launched on a sample as two oppositely polarized circular states. These states reflect from sample surfaces and interfere with the corresponding states of the reference arm. A custom spectrometer, which is designed to simplify camera alignment, separates the orthogonal channels and records the interference-related oscillations on both spectra. Inverse Fourier transform of the spectral oscillations in k-space yields complex depth profiles, whose amplitudes and phase difference are related to reflectivity and Faraday rotation within the sample, respectively. Information along a full depth profile is produced at the camera speed without performing an axial scan for a multisurface sample. System sensitivity for the Faraday rotation measurement is 0.86 min of arc. Verdet constants of clear liquids and turbid media are measured at 687 nm.

  16. Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.

    PubMed

    Monico, Letizia; Rosi, Francesca; Miliani, Costanza; Daveri, Alessia; Brunetti, Brunetto G

    2013-12-01

    In this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome artworks analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the νs(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks.

  17. Analysis of Complex Carbohydrate Composition in Plant Cell Wall Using Fourier Transformed Mid-Infrared Spectroscopy (FT-IR).

    PubMed

    Badhan, Ajay; Wang, Yuxi; McAllister, Tim A

    2017-01-01

    Fourier transformed mid-infrared spectroscopy (FTIR) is a powerful tool for compositional analysis of plant cell walls (Acebes et al., Front Plant Sci 5:303, 2014; Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Badhan et al., BioMed Res Int 2015: 562952, 2015; Roach et al., Plant Physiol 156:1351-1363, 2011). The infrared spectrum generates a fingerprint of a sample with absorption peaks corresponding to the frequency of vibrations between the bonds of the atoms making up the material. Here, we describe a method focused on the use of FTIR in combination with principal component analysis (PCA) to characterize the composition of the plant cell wall. This method has been successfully used to study complex enzyme saccharification processes like rumen digestion to identify recalcitrant moieties in low-quality forage which resist rumen digestion (Badhan et al., BioMed Res Int 2015: 562952, 2015), as well as to characterize cell wall mutant lines or transgenic lines expressing exogenous hydrolases (Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Roach et al., Plant Physiol 156:1351-1363, 2011). The FTIR method described here facilitates high-throughput identification of the major compositional differences across a large set of samples in a low cost and nondestructive manner.

  18. Time-Resolved Visible and Infrared Study of the Cyano Complexes of Myoglobin and of Hemoglobin I from Lucina pectinata

    PubMed Central

    Helbing, Jan; Bonacina, Luigi; Pietri, Ruth; Bredenbeck, Jens; Hamm, Peter; van Mourik, Frank; Chaussard, Frédéric; Gonzalez-Gonzalez, Alejandro; Chergui, Majed; Ramos-Alvarez, Cacimar; Ruiz, Carlos; López-Garriga, Juan

    2004-01-01

    The dynamics of the ferric CN complexes of the heme proteins Myoglobin and Hemoglobin I from the clam Lucina pectinata upon Soret band excitation is monitored using infrared and broad band visible pump-probe spectroscopy. The transient response in the UV-vis spectral region does not depend on the heme pocket environment and is very similar to that known for ferrous proteins. The main feature is an instantaneous, broad, short-lived absorption signal that develops into a narrower red-shifted Soret band. Significant transient absorption is also observed in the 360–390 nm range. At all probe wavelengths the signal decays to zero with a longest time constant of 3.6 ps. The infrared data on MbCN reveal a bleaching of the C ≡ N stretch vibration of the heme-bound ligand, and the formation of a five-times weaker transient absorption band, 28 cm−1 lower in energy, within the time resolution of the experiment. The MbC ≡ N stretch vibration provides a direct measure for the return of population to the ligated electronic (and vibrational) ground state with a 3–4 ps time constant. In addition, the CN-stretch frequency is sensitive to the excitation of low frequency heme modes, and yields independent information about vibrational cooling, which occurs on the same timescale. PMID:15345566

  19. Portrait of the Polana-Eulalia family complex: Surface homogeneity revealed from near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Pinilla-Alonso, Noemí; de León, J.; Walsh, K. J.; Campins, H.; Lorenzi, V.; Delbo, M.; DeMeo, F.; Licandro, J.; Landsman, Z.; Lucas, M. P.; Alí-Lagoa, V.; Burt, B.

    2016-08-01

    The inner asteroid belt is an important source of near-Earth asteroids (NEAs). Dynamical studies of the inner asteroid belt have identified several families overlapping in proper orbital elements, including the Polana and Eulalia families that contain a large fraction of the low-albedo asteroids in this region. We present results from two coordinated observational campaigns to characterize this region through near-infrared (NIR) spectroscopy. These campaigns ran from August 2012 to May 2014 and used the NASA Infrared Telescope Facility and the Telescopio Nazionale Galileo. The observations focused on objects within these families or in the background, with low albedo (pv ≤ 0.1) and low inclination (iP ≤ 7°). We observed 63 asteroids (57 never before observed in the NIR): 61 low-albedo objects and two interlopers, both compatible with S- or E- taxonomical types. We found our sample to be spectrally homogeneous in the NIR. The sample shows a continuum of neutral to moderately-red concave-up spectra, very similar within the uncertainties. Only one object in the sample, asteroid (3429) Chuvaev, has a blue spectrum, with a slope (S‧ = - 1.33 ± 0.21%/1000 Å) significantly different from the average spectrum (S‧ = 0.68 ± 0.68%/1000 Å). This spectral homogeneity is independent of membership in families or the background population. Furthermore, we show that the Eulalia and Polana families cannot be distinguished using NIR data. We also searched for rotational variability on the surface of (495) Eulalia which we do not detect. (495) Eulalia shows a red concave-up spectrum with an average slope S‧ = 0.91 ± 0.60%/1000 Å, very similar to the average slope of our sample. The spectra of two targets of sample-return missions, (101955) Bennu, target of NASA's OSIRIS-Rex and (162173) 1999 JU3 target of the Japanese Space Agency's Hayabusa-2, are very similar to our average spectrum, which would be compatible with an origin in this region of the inner belt.

  20. Study of inclusion complex formation between tropaeolin OO and beta-cyclodextrin by spectrophotometry and Infrared spectroscopy.

    PubMed

    Wang, Huai You; Han, Juan; Feng, Xia Guang; Pang, Yan Ling

    2006-09-01

    The mechanism of the inclusion of tropaeolin OO (TPOO) and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The inclusion depth of the guest molecule in the host molecule was demonstrated by infrared spectrometry. Effect of the pH, concentrations of beta-CD, solvents and ionic strength on the inclusion of TPOO and beta-CD were examined. The result showed that TPOO reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 1.50 x 10(3) l mol(-1). The thermodynamic parameters of inclusion reaction, DeltaG degrees , DeltaH degrees and DeltaS degrees were obtained.

  1. CRADA Final Report, 2011S003, Faraday Technologies

    SciTech Connect

    Faraday Technologies

    2012-12-12

    This Phase I SBIR program addressed the need for an improved manufacturing process for electropolishing niobium RF superconducting cavities for the International Linear Collider (ILC). The ILC is a proposed particle accelerator that will be used to gain a deeper understanding of the forces of energy and matter by colliding beams of electrons and positrons at nearly the speed of light. The energy required for this to happen will be achieved through the use of advanced superconducting technology, specifically ~16,000 RF superconducting cavities operating at near absolute zero. The RF superconductor cavities will be fabricated from highly pure Nb, which has an extremely low surface resistance at 2 Kelvin when compared to other materials. To take full advantage of the superconducting properties of the Nb cavities, the inner surface must be a) polished to a microscale roughness < 0.1 µm with removal of at least 100 µm of material, and b) cleaned to be free of impurities that would degrade performance of the ILC. State-of-the-art polishing uses either chemical polishing or electropolishing, both of which require hydrofluoric acid to achieve breakdown of the strong passive film on the surface. In this Phase I program, Faraday worked with its collaborators at the Thomas Jefferson National Accelerator Facility (JLab) to demonstrate the feasibility of an electropolishing process for pure niobium, utilizing an environmentally benign alternative to chemical or electrochemical polishing electrolytes containing hydrofluoric acid. Faraday utilized a 31 wt% aqueous sulfuric acid solution (devoid of hydrofluoric acid) in conjunction with the FARADAYICSM Process, which uses pulse/pulse reverse fields for electropolishing, to demonstrate the ability to electropolish niobium to the desired surface finish. The anticipated benefits of the FARADAYICSM Electropolishing process will be a simpler, safer, and less expensive method capable of surface finishing high purity niobium cavities

  2. A Faraday effect position sensor for interventional magnetic resonance imaging.

    PubMed

    Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W

    2006-02-21

    An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

  3. Todd, Faraday and the electrical basis of brain activity.

    PubMed

    Reynolds, Edward

    2007-10-01

    The origins of our understanding of brain electricity and electrical discharges in epilepsy can be traced to Robert Bentley Todd (1809-60). Todd was influenced by his contemporary in London, Michael Faraday (1791-1867), who in the 1830 s and 1840 s was laying the foundations of our modern understanding of electromagnetism. Todd's concept of nervous polarity, generated in nerve vesicles and transmitted in nerve fibres (neurons in later terminology), was confirmed a century later by the Nobel Prize-winning work of Hodgkin and Huxley, who demonstrated the ionic basis of neuro-transmission, involving the same ions which had had been discovered by Faraday's mentor, Sir Humphry Davy (1778-1829).

  4. Intracavity Faraday modulation spectroscopy (INFAMOS): A tool for radical detection

    NASA Astrophysics Data System (ADS)

    Gianella, Michele; Pinto, Tomas H. P.; Wu, Xia; Ritchie, Grant A. D.

    2017-08-01

    We present the intra-cavity Faraday modulation spectroscopy technique, whereby optical feedback cavity-enhanced spectroscopy is coupled with Faraday modulation spectroscopy to greatly enhance the interaction path length of a laser beam with a paramagnetic sample in a magnetic field. We describe a first prototype based upon a cw quantum cascade laser targeting a selection of fundamental rovibrational R-branch transitions of nitric oxide (1890 cm-1), consisting of a linear cavity (finesse F =6300 ) and a water-cooled solenoid. We demonstrate a minimum detectable Verdet constant of Vmin=4.7 ×10-14 rad cm-1 G-1 H z-1/2 (at SNR = 1), corresponding to a single-pass rotation angle of 1.6 ×10-10 rad Hz-1/2 and a limit of detection of 0.21 ppbv Hz-1/2 NO.

  5. Water binding energies of [Pb(amino acid-H)H2O]+ complexes determined by blackbody infrared radiative dissociation.

    PubMed

    Burt, Michael B; Decker, Sarah G A; Fridgen, Travis D

    2012-11-21

    The water binding energies (E(0)) of eight deprotonated Pb(2+)-amino acid (Aa) complexes of the form [Pb(Aa-H)H(2)O](+) (Aa = Gly, Ala, Val, Leu, Ile, Phe, Glu, and Lys) were determined using blackbody infrared radiative dissociation (BIRD). A Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer was used to trap ions generated by electrospray ionization (ESI) in a "zero"-pressure (~10(-10) torr) cell where dissociation can only occur by absorption of thermally generated photons. Since the [Pb(Aa-H)H(2)O](+) complexes have relatively few vibrational degrees of freedom (36-78) and are within the slow-exchange kinetic limit, the master equation was solved to extract meaningful threshold dissociation energies and thermal unimolecular dissociation rate constants (k(uni)). The master equation analysis uses variable reaction coordinate transition state theory (VRC-TST) to minimize the Rice-Ramsperger-Kassel-Marcus (RRKM) dissociation rate constants. The determined water binding energies range from 76.6 to 113.6 kJ mol(-1), and agree well with 0 K dissociation energies calculated using the B3LYP/6-31+G(d,p) and MP2(full)/6-311++G(2d,2p)//B3LYP/6-31+G(d,p) methods. The relative strengths of the binding energies reflect the known structural isomers (A-, B-, C-, and D-type) of these [Pb(Aa-H)H(2)O](+) complexes.

  6. Monitoring redox-dependent contribution of lipids in Fourier transform infrared difference spectra of complex I from Escherichia coli.

    PubMed

    Hielscher, Ruth; Wenz, Tina; Stolpe, Stefan; Hunte, Carola; Friedrich, Thorsten; Hellwig, Petra

    2006-07-01

    Biochemical and crystallographic studies have shown that phospholipids are essential for the integrity and activity of membrane proteins. In the study presented here, we use electrochemically induced Fourier transform infrared (FTIR) spectroscopy to demonstrate variations occurring upon the presence and absence of lipids in NADH:ubiquinone oxidoreductase (complex I) from Escherchia coli by following the C=O vibration of the lipid molecule. Complex I is activated in the presence of lipids. Interestingly, in electrochemically induced FTIR difference spectra of complex I from E. coli, a new signal at 1744/1730 cm(-1) appears after addition of E. coli polar lipids, concomitant with the oxidized or reduced form, respectively. Absorbance spectra of liposomes from mixed lipids at different pH values demonstrate shifts for the carbonyl vibration depending on the environment. On this basis we suggest that lipids, though not redox active themselves, contribute in reaction-induced FTIR difference spectra, if a change occurs in the direct environment of the lipid during the observed reaction or coupled processes.

  7. Infrared spectroscopy of Mg–CO{sub 2} and Al–CO{sub 2} complexes in helium nanodroplets

    SciTech Connect

    Thomas, Brandon J.; Harruff-Miller, Barbara A.; Bunker, Christopher E.; Lewis, William K.

    2015-05-07

    The catalytic reduction of CO{sub 2} to produce hydrocarbon fuels is a topic that has gained significant attention. Development of efficient catalysts is a key enabler to such approaches, and metal-based catalysts have shown promise towards this goal. The development of a fundamental understanding of the interactions between CO{sub 2} molecules and metal atoms is expected to offer insight into the chemistry that occurs at the active site of such catalysts. In the current study, we utilize helium droplet methods to assemble complexes composed of a CO{sub 2} molecule and a Mg or Al atom. High-resolution infrared (IR) spectroscopy and optically selected mass spectrometry are used to probe the structure and binding of the complexes, and the experimental observations are compared with theoretical results determined from ab initio calculations. In both the Mg–CO{sub 2} and Al–CO{sub 2} systems, two IR bands are obtained: one assigned to a linear isomer and the other assigned to a T-shaped isomer. In the case of the Mg–CO{sub 2} complexes, the vibrational frequencies and rotational constants associated with the two isomers are in good agreement with theoretical values. In the case of the Al–CO{sub 2} complexes, the vibrational frequencies agree with theoretical predictions; however, the bands from both structural isomers exhibit significant homogeneous broadening sufficient to completely obscure the rotational structure of the bands. The broadening is consistent with an upper state lifetime of 2.7 ps for the linear isomer and 1.8 ps for the T-shaped isomer. The short lifetime is tentatively attributed to a prompt photo-induced chemical reaction between the CO{sub 2} molecule and the Al atom comprising the complex.

  8. Laser Infrared Desorption Spectroscopy to Detect Complex Organic Molecules on Icy Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Sollit, Luke S.; Beegle, Luther W.

    2008-01-01

    Laser Desorption-Infrared Spectroscopy (LD-IR) uses an IR laser pulse to desorb surface materials while a spectrometer measures the emission spectrum of the desorbed materials (Figure 1). In this example, laser desorption operates by having the incident laser energy absorbed by near surface material (10 microns in depth). This desorption produces a plume that exists in an excited state at elevated temperatures. A natural analog for this phenomenon can be observed when comets approach the sun and become active and individual molecular emission spectra can be observed in the IR [1,2,3,4,5]. When this occurs in comets, the same species that initially emit radiation down to the ground state are free to absorb it, reducing the amount of detectable emission features. The nature of our technique results in absorption not occurring, because the laser pulse could easily be moved away form the initial desorption plume, and still have better spatial resolution then reflectance spectroscopy. In reflectance spectroscopy, trace components have a relatively weak signal when compared to the entire active nature of the surface. With LDIR, the emission spectrum is used to identify and analyze surface materials.

  9. Laser Infrared Desorption Spectroscopy to Detect Complex Organic Molecules on Icy Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Sollit, Luke S.; Beegle, Luther W.

    2008-01-01

    Laser Desorption-Infrared Spectroscopy (LD-IR) uses an IR laser pulse to desorb surface materials while a spectrometer measures the emission spectrum of the desorbed materials (Figure 1). In this example, laser desorption operates by having the incident laser energy absorbed by near surface material (10 microns in depth). This desorption produces a plume that exists in an excited state at elevated temperatures. A natural analog for this phenomenon can be observed when comets approach the sun and become active and individual molecular emission spectra can be observed in the IR [1,2,3,4,5]. When this occurs in comets, the same species that initially emit radiation down to the ground state are free to absorb it, reducing the amount of detectable emission features. The nature of our technique results in absorption not occurring, because the laser pulse could easily be moved away form the initial desorption plume, and still have better spatial resolution then reflectance spectroscopy. In reflectance spectroscopy, trace components have a relatively weak signal when compared to the entire active nature of the surface. With LDIR, the emission spectrum is used to identify and analyze surface materials.

  10. Oscillon dynamics and rogue wave generation in Faraday surface ripples.

    PubMed

    Xia, H; Maimbourg, T; Punzmann, H; Shats, M

    2012-09-14

    We report new experimental results which suggest that the generation of extreme wave events in the Faraday surface ripples is related to the increase in the horizontal mobility of oscillating solitons (oscillons). The analysis of the oscillon trajectories in a horizontal plane shows that at higher vertical acceleration, oscillons move chaotically, merge and form enclosed areas on the water surface. The probability of the formation of such craters, which precede large wave events, increases with the increase in horizontal mobility.

  11. Improved method for Faraday current sensor data processing

    NASA Astrophysics Data System (ADS)

    Ferrari, José A.; Perciante, César D.; Lagos, Alejandro; Frins, Erna M.

    2001-11-01

    There are several practical problems that have made difficult the prompt application of Faraday current sensors in industrial environments. Two of them are the multiplicative noise generated by mechanical vibrations and the normalization of the output signal. In this paper we propose a logarithmical processing and a posterior bandpass filtering of the sensor data in order to solve simultaneously both issues. Experimental results demonstrating the viability of the procedure and a comparison with standard processing methods are presented.

  12. Triangular-shaped bulk optic glass Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Chu, Beatrice C.; Ning, Yanong N.; Jackson, David A.

    1993-03-01

    A new triangular topology for a bulk optic Faraday current sensor is presented with a demonstrated resolution of 20 mA/(root)Hz over a measurement range from 1 to 3000 A. The sensitivity of the system was 2.35 X 10-5 rad/A. This sensor is relatively easy to fabricate and overcome problems encountered using current sensors based upon bulk optic 'square' configurations and all fiber systems.

  13. A new approach for miniaturization of multiple faraday cup collectors.

    SciTech Connect

    Banar, J. C.; Chamberlin, E. P.; Poths, J.; Perrin, R. E.; Chastagner, P.

    2002-01-01

    The mass spectrometry section in CST-7 has been working for several years on a novel so0lution to overcome the size and placement restrictions of multiple Faraday cup collectors. Use of simultaneous collection of multiple isotopes both increases precision in the isotopic measurements and shortens the data collection time. Our application is for the measurement of the isotopic composition of Xe, ionized in a source that produces a large (10{sup -11} amp) but variable ion beam.

  14. Infrared study and phase transformation of the new lithium-diphenyl carbazide complex (LiDPC)

    NASA Astrophysics Data System (ADS)

    El-Kabbany, F.; Taha, S.; Hafez, M.; Abdel Aziz, N. R.

    2015-07-01

    A complete IR investigation (400-4000 cm-1) of orthorhombic, amorphous DPC and crystalline LiDPC (at room temperature and 80 °C) is performed and new results are reported. Introducing lithium ions into diphenyl carbazide C13H14N4O forms a completely new complex associated with new properties. The IR spectroscopic analysis includes measurements and interpretation of the IR spectral band shape, intensities, and frequencies of the internal modes of vibrations. The principle modes of vibrations of amorphous DPC found to be 3445 cm-1, 3292 cm-1, 3052 cm-1, 1670 cm-1, 1602 cm-1, 1495 cm-1, 1305 cm-1, 1254 cm-1, 974 cm-1, and 577 cm-1 correspond to normal vibrations of Nsbnd H, Csbnd H, Nsbnd N, Cdbnd O and monosubstituted benzene. A marked change could be recorded for these modes of vibrations in the presence of Li+ ions. The results strongly confirm the formation of a metal-organic complex. Anomalous spectroscopic changes could be recorded in LiDPC spectra. A proposed Li+ position in LiDPC complex is proposed. X-ray diffraction analysis is used to find out the crystal structure and parameters of LiDPC complex. The results obtained show triclinic crystal structure with a = 5.6929 Å, b = 7.6378 Å, c = 17.8739 Å, α = 119.176°, β = 63.322°, γ = 85.378°. The results reveal the presence of an order-disorder phase transition in LiDPC complex at 60 °C. The transformation process is monitored by clear variations in the spectral shape, band intensities and new eight different modes appeared in the high temperature disordered phase. An energy model is suggested for the interpretation of such phase transition process.

  15. A desktop Faraday rotation instrument in the ultraviolet.

    PubMed

    Ström, Valter; Rao, K V

    2008-02-01

    A simple versatile desktop instrument for the measurement of Faraday rotation in the ultraviolet range has been designed and constructed. A high pressure short arc mercury lamp is used for the light source. By using interference filter for mercury, the desired wavelength of the available lines for mercury (e.g., 365, 405, and 436 nm) is selected. Our instrument measures hysteresis loops in magnetic fields up to 900 kAm within a few minutes. With a light beam intensity monitor, the detrimental effect from fluctuations in the light source has been virtually eliminated. The instrument can operate at photocurrents from the picoampere regime and above with a Faraday rotation sensitivity of around 1 millideg. By incorporating a higher order Taylor expansion approach, we improve the linearity of the Faraday rotation to transmitted light relationship by two orders of magnitude. The electronics is custom designed analog type, rendering relaxed dynamic requirements for the analog-to-digital converter. The design is fully protected from ambient light which makes operation with the equipment in darkness superfluous; neither does it need any optical table. The data acquisition and operation of the instrument are fully supported by a LABVIEW program. Measurements on a magnetite thin film and on microscope cover glass are given as examples for the performance and sensitivity of the equipment.

  16. A desktop Faraday rotation instrument in the ultraviolet

    NASA Astrophysics Data System (ADS)

    Ström, Valter; Rao, K. V.

    2008-02-01

    A simple versatile desktop instrument for the measurement of Faraday rotation in the ultraviolet range has been designed and constructed. A high pressure short arc mercury lamp is used for the light source. By using interference filter for mercury, the desired wavelength of the available lines for mercury (e.g., 365, 405, and 436 nm) is selected. Our instrument measures hysteresis loops in magnetic fields up to 900 kA/m within a few minutes. With a light beam intensity monitor, the detrimental effect from fluctuations in the light source has been virtually eliminated. The instrument can operate at photocurrents from the picoampere regime and above with a Faraday rotation sensitivity of around 1 millideg. By incorporating a higher order Taylor expansion approach, we improve the linearity of the Faraday rotation to transmitted light relationship by two orders of magnitude. The electronics is custom designed analog type, rendering relaxed dynamic requirements for the analog-to-digital converter. The design is fully protected from ambient light which makes operation with the equipment in darkness superfluous; neither does it need any optical table. The data acquisition and operation of the instrument are fully supported by a LABVIEW program. Measurements on a magnetite thin film and on microscope cover glass are given as examples for the performance and sensitivity of the equipment.

  17. Development and first experimental tests of Faraday cup array.

    PubMed

    Prokůpek, J; Kaufman, J; Margarone, D; Krůs, M; Velyhan, A; Krása, J; Burris-Mog, T; Busold, S; Deppert, O; Cowan, T E; Korn, G

    2014-01-01

    A new type of Faraday cup, capable of detecting high energy charged particles produced in a high intensity laser-matter interaction environment, has recently been developed and demonstrated as a real-time detector based on the time-of-flight technique. An array of these Faraday cups was designed and constructed to cover different observation angles with respect to the target normal direction. Thus, it allows reconstruction of the spatial distribution of ion current density in the subcritical plasma region and the ability to visualise its time evolution through time-of-flight measurements, which cannot be achieved with standard laser optical interferometry. This is a unique method for two-dimensional visualisation of ion currents from laser-generated plasmas. A technical description of the new type of Faraday cup is introduced along with an ad hoc data analysis procedure. Experimental results obtained during campaigns at the Petawatt High-Energy Laser for Heavy Ion Experiments (GSI, Darmstadt) and at the Prague Asterix Laser System (AS CR) are presented. Advantages and limitations of the used diagnostic system are discussed.

  18. Effects of interband transitions on Faraday rotation in metallic nanoparticles.

    PubMed

    Wysin, G M; Chikan, Viktor; Young, Nathan; Dani, Raj Kumar

    2013-08-14

    The Faraday rotation in metallic nanoparticles is considered based on a quantum model for the dielectric function ϵ(ω) in the presence of a DC magnetic field B. We focus on effects in ϵ(ω) due to interband transitions (IBTs), which are important in the blue and ultraviolet for noble metals used in plasmonics. The dielectric function is found using the perturbation of the electron density matrix due to the optical field of the incident electromagnetic radiation. The calculation is applied to transitions between two bands (d and p, for example) separated by a gap, as one finds in gold at the L-point of the Fermi surface. The result of the DC magnetic field is a shift in the effective optical frequency causing IBTs by ±μBB/ħ, where opposite signs are associated with left/right circular polarizations. The Faraday rotation for a dilute solution of 17 nm diameter gold nanoparticles is measured and compared with both the IBT theory and a simpler Drude model for the bound electron response. Effects of the plasmon resonance mode on Faraday rotation in nanoparticles are also discussed.

  19. Toward instructional design principles: Inducing Faraday's law with contrasting cases

    NASA Astrophysics Data System (ADS)

    Kuo, Eric; Wieman, Carl E.

    2016-06-01

    Although physics education research (PER) has improved instructional practices, there are not agreed upon principles for designing effective instructional materials. Here, we illustrate how close comparison of instructional materials could support the development of such principles. Specifically, in discussion sections of a large, introductory physics course, a pair of studies compare two instructional strategies for teaching a physics concept: having students (i) explain a set of contrasting cases or (ii) apply and build on previously learned concepts. We compare these strategies for the teaching of Faraday's law, showing that explaining a set of related contrasting cases not only improves student performance on Faraday's law questions over building on a previously learned concept (i.e., Lorentz force), but also prepares students to better learn subsequent topics, such as Lenz's law. These differences persist to the final exam. We argue that early exposure to contrasting cases better focuses student attention on a key feature related to both concepts: change in magnetic flux. Importantly, the benefits of contrasting cases for both learning and enjoyment are enhanced for students who did not first attend a Faraday's law lecture, consistent with previous research suggesting that being told a solution can circumvent the benefits of its discovery. These studies illustrate an experimental approach for understanding how the structure of activities affects learning and performance outcomes, a first step toward design principles for effective instructional materials.

  20. Effects of Faraday Rotation Observed in Filter Magnetograph Data

    NASA Technical Reports Server (NTRS)

    Hagyard, Mona J.; Adams, Mitzi L.; Smith, J. E.; West, Edward A.

    1999-01-01

    In this paper we analyze the effects of Faraday rotation on the azimuth of the transverse magnetic field from observations taken with the Marshall Space Flight Center's vector magnetograph for a simple sunspot observed on June 9, 1985. Vector magnetograms were obtained over the wavelength interval of 170 mA redward of line center of the Fe I 5250.22 A spectral line to 170 mA to the blue, in steps of 10 mA. These data were analyzed to produce the variation of the azimuth as a function of wavelength at each pixel over the field of vi ew of the sunspot. At selected locations in the sunspot, curves of the observed variation of azimuth with wavelength were compared with model calculations for the amount of Faraday rotation of the azimuth. From these comparisons we derived the amount of rotation as functions of bo th the magnitude and inclination of the sunspot's field and deduced the ranges of these field values for which Faraday rotation presents a significant problem in observations taken near the center of a spectral line.

  1. Todd, Faraday, and the electrical basis of brain activity.

    PubMed

    Reynolds, Edward H

    2004-09-01

    Robert Bentley Todd (1809-60) was the UK's first eminent neurologist and neuroscientist. An anatomist, physiologist, and clinical scientist with an interest in the nervous system, he was the first to confirm the electrical basis of brain activity in the 1840s. He was influenced by his contemporary, Michael Faraday at the Royal Institution, and by two colleagues at King's College, John Daniell and Charles Wheatstone, who were also working at the cutting edge of electrical science. Todd conceived of nervous polarity (force) generated in nervous centres and compared this with the polar force of voltaic electricity developed in the galvanic battery. He brilliantly foresaw each nerve vesicle (cell) and its related fibres (ie, neuron) as a distinct apparatus for the development and transmission of nervous polarity. Epilepsy was the result of periodic unnatural development of nervous force leading to the "disruptive discharge" described by Faraday. Faraday, who studied animal electricity in the Gymnotus (electric eel), and Todd saw nervous polarity as a higher form of interchangeable energy.

  2. Effects of Faraday Rotation Observed in Filter Magnetograph Data

    NASA Technical Reports Server (NTRS)

    Hagyard, Mona J.; Adams, Mitzi L.; Smith, J. E.; West, Edward A.

    1999-01-01

    In this paper we analyze the effects of Faraday rotation on the azimuth of the transverse magnetic field from observations taken with the Marshall Space Flight Center's vector magnetograph for a simple sunspot observed on June 9, 1985. Vector magnetograms were obtained over the wavelength interval of 170 mA redward of line center of the Fe I 5250.22 A spectral line to 170 mA to the blue, in steps of 10 mA. These data were analyzed to produce the variation of the azimuth as a function of wavelength at each pixel over the field of vi ew of the sunspot. At selected locations in the sunspot, curves of the observed variation of azimuth with wavelength were compared with model calculations for the amount of Faraday rotation of the azimuth. From these comparisons we derived the amount of rotation as functions of bo th the magnitude and inclination of the sunspot's field and deduced the ranges of these field values for which Faraday rotation presents a significant problem in observations taken near the center of a spectral line.

  3. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    NASA Astrophysics Data System (ADS)

    Pare, Dylan; Wang, Q. Daniel; Kamieneski, Patrick; Sullivan, Kendall

    2017-01-01

    Extragalactic magnetic fields are a poorly understood element of galaxies that are likely to play an important role in galaxy formation and evolution. Until recently, however, there was no way to observe these fields to a high level of detail, making it difficult to map the spatial distribution of these fields to any high degree of accuracy. Fortunately, a new technique known as Faraday Rotation Measure Synthesis allows for a more precise analysis of galactic magnetism. This technique uses the observed Faraday rotation of polarized emission from background sources to map the magnetic field of a foreground galaxy. This Faraday rotation occurs when the polarized emission encounters ionized, magnetized gas within the galaxy, causing the emission to be rotated by an amount proportional the magnetic field subjected to the ionized gas. Working as part of CHANG-ES (Continuum HAlos in Nearby Galaxies - an EVLA Survey), we have applied this technique in order to learn about the distribution of magnetic fields in the disks and halos of edge-on spiral galaxies. We will present maps of the galactic magnetic fields of CHANG-ES galaxies using this technique, indicating the potential of this technique in successfully mapping these distant fields.

  4. Model of fractionalization of Faraday lines in compact electrodynamics

    NASA Astrophysics Data System (ADS)

    Geraedts, Scott D.; Motrunich, Olexei I.

    2014-12-01

    Motivated by ideas of fractionalization and intrinsic topological order in bosonic models with short-range interactions, we consider similar phenomena in formal lattice gauge theory models. Specifically, we show that a compact quantum electrodynamics (CQED) can have, besides the familiar Coulomb and confined phases, additional unusual confined phases where excitations are quantum lines carrying fractions of the elementary unit of electric field strength. We construct a model that has N -tupled monopole condensation and realizes 1 /N fractionalization of the quantum Faraday lines. This phase has another excitation which is a ZN quantum surface in spatial dimensions five and higher, but can be viewed as a quantum line or a quantum particle in four or three spatial dimensions, respectively. These excitations have statistical interactions with the fractionalized Faraday lines; for example, in three spatial dimensions, the particle excitation picks up a Berry phase of ei 2 π /N when going around the fractionalized Faraday line excitation. We demonstrate the existence of this phase by Monte Carlo simulations in (3+1) space-time dimensions.

  5. Faraday rotation data analysis with least-squares elliptical fitting

    SciTech Connect

    White, Adam D.; McHale, G. Brent; Goerz, David A.; Speer, Ron D.

    2010-10-15

    A method of analyzing Faraday rotation data from pulsed magnetic field measurements is described. The method uses direct least-squares elliptical fitting to measured data. The least-squares fit conic parameters are used to rotate, translate, and rescale the measured data. Interpretation of the transformed data provides improved accuracy and time-resolution characteristics compared with many existing methods of analyzing Faraday rotation data. The method is especially useful when linear birefringence is present at the input or output of the sensing medium, or when the relative angle of the polarizers used in analysis is not aligned with precision; under these circumstances the method is shown to return the analytically correct input signal. The method may be pertinent to other applications where analysis of Lissajous figures is required, such as the velocity interferometer system for any reflector (VISAR) diagnostics. The entire algorithm is fully automated and requires no user interaction. An example of algorithm execution is shown, using data from a fiber-based Faraday rotation sensor on a capacitive discharge experiment.

  6. Midplane Faraday rotation: A densitometer for large tokamaks

    NASA Astrophysics Data System (ADS)

    Jobes, F. C.; Mansfield, D. K.

    1992-10-01

    The density in a large tokamak such as International Thermonuclear Experimental Reactor (ITER), or any of the proposed future US machines, can be determined by measuring the Faraday rotation of a 10.6 μm laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then ne(R) can be readily obtained with a simple Abel inversion about the center line of the tokamak. For a large machine, operated at a full field of 30 T m and a density of 2×1020/m3, the rotation angle would be quite large-about 60° for two passes. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 ``fringe,'' the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that ITER, or any large tokamak, existing or proposed, would be well served even at low densities by a midplane Faraday rotation densitometer of ˜64 channels.

  7. Faraday rotation dispersion microscopy imaging of diamagnetic and chiral liquids with pulsed magnetic field.

    PubMed

    Suwa, Masayori; Nakano, Yusuke; Tsukahara, Satoshi; Watarai, Hitoshi

    2013-05-21

    We have constructed an experimental setup for Faraday rotation dispersion imaging and demonstrated the performance of a novel imaging principle. By using a pulsed magnetic field and a polarized light synchronized to the magnetic field, quantitative Faraday rotation images of diamagnetic organic liquids in glass capillaries were observed. Nonaromatic hydrocarbons, benzene derivatives, and naphthalene derivatives were clearly distinguished by the Faraday rotation images due to the difference in Verdet constants. From the wavelength dispersion of the Faraday rotation images in the visible region, it was found that the resonance wavelength in the UV region, which was estimated based on the Faraday B-term, could be used as characteristic parameters for the imaging of the liquids. Furthermore, simultaneous acquisition of Faraday rotation image and natural optical rotation image was demonstrated for chiral organic liquids.

  8. Infrared spectra of arsine-ozone complexes, reaction products, and photolysis products in solid argon

    SciTech Connect

    Andrews, L.; Withnall, R.; Moores, B.W. )

    1989-02-23

    Codeposition of AsH{sub 3} and O{sub 3} at high dilution in argon gave a large yield of AsH{sub 3}-O{sub 3} complex and a small yield of reaction products identified as cis- and trans-H{sub 2}AsOH. The complex photolyzed with red light, which showed that a specific interaction within the complex markedly increased the red photodissociation probability for the O{sub 3} submolecule. The red photolysis products were H{sub 3}AsO, H{sub 2}AsOH, and an intermediate species tentatively identified as HAsO. Further blue and near-UV irradiations destroyed HAsO and produced HOAsO{sub 2}. This AsH{sub 3} and O{sub 3} study parallels earlier PH{sub 3} work and shows that AsH{sub 3} is slightly more reactive than PH{sub 3} with O{sub 3}.

  9. Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography

    NASA Astrophysics Data System (ADS)

    Ideguchi, Shinsuke; Tashiro, Yuichi; Akahori, Takuya; Takahashi, Keitaro; Ryu, Dongsu

    2017-07-01

    Faraday tomography allows astronomers to probe the distribution of the magnetic field along the line of sight (LOS), but that can be achieved only after the Faraday spectrum is interpreted. However, the interpretation is not straightforward, mainly because the Faraday spectrum is complicated due to a turbulent magnetic field; it ruins the one-to-one relation between the Faraday depth and the physical depth, and appears as many small-scale features in the Faraday spectrum. In this paper, by employing “simple toy models” for the magnetic field, we describe numerically as well as analytically the characteristic properties of the Faraday spectrum. We show that the Faraday spectrum along “multiple LOSs” can be used to extract the global properties of the magnetic field. Specifically, considering face-on spiral galaxies and modeling turbulent magnetic field as a random field with a single coherence length, we numerically calculate the Faraday spectrum along a number of LOSs and its shape-characterizing parameters, that is, the moments. When multiple LOSs cover a region of ≳(10 coherence length)2, the shape of the Faraday spectrum becomes smooth and the shape-characterizing parameters are well specified. With the Faraday spectrum constructed as a sum of Gaussian functions with different means and variances, we analytically show that the parameters are expressed in terms of the regular and turbulent components of the LOS magnetic field and the coherence length. We also consider the turbulent magnetic field modeled with a power-law spectrum, and study how the magnetic field is revealed in the Faraday spectrum. Our work suggests a way to obtain information on the magnetic field from a Faraday tomography study.

  10. Observation of two-dimensional Faraday waves in extremely shallow depth.

    PubMed

    Li, Xiaochen; Yu, Zhengyue; Liao, Shijun

    2015-09-01

    A family of two-dimensional Faraday waves in extremely shallow depth (1 mm to 2 mm) of absolute ethanol are observed experimentally using a Hele-Shaw cell that vibrates vertically. The same phenomena are not observed by means of water, ethanol solution, and silicone oil. These Faraday waves are quite different from the traditional ones. These phenomena are helpful to deepen and enrich our understandings about Faraday waves, and besides provide a challenging problem for computational fluid dynamics.

  11. Complex biopolymeric systems at stalk/epicuticular wax plant interfaces: a near infrared spectroscopy study of the sugarcane example.

    PubMed

    Purcell, Deborah E; O'Shea, Michael G; Kokot, Serge

    2009-08-01

    Naturally occurring macromolecules present at the epicuticular wax/stalk tissue interface of sugarcane were investigated using near infrared spectroscopy (NIRS). Investigations of water, cellulose, and wax-cellulose interrelationships were possible using NIRS methods, where in the past many different techniques have been required. The sugarcane complex interface was used as an example of typical phenomena found at plant leaf/stalk interfaces. This detailed study showed that sugarcane cultivars exhibit spectral differences in the CH(n), water OH, and cellulose OH regions, reflecting the presence of epicuticular wax, epidermis, and ground tissue. Spectrally complex water bands (5276 cm(-1) and 7500-6000 cm(-1)) were investigated via freeze-drying experiments which revealed sequentially a complex band substructure (7500-6000 cm(-1)), a developing weak H-bonding system ( approximately 7301 cm(-1)), and strong H-bonding ( approximately 7062 cm(-1)) assigned to water-cellulose interactions. Principal component analysis techniques clarified complex band trends that developed during the desorption experiment. Bands from wax-free stalk were minimized in the 4327-4080 cm(-1) region (C--H(n) vibrational modes associated with long chain fatty compounds), while bands from the stalk tissue (particularly lignin and moisture) became more pronounced. This work is a comprehensive guide to similar studies by scientists involved in a variety of plant and fiber research fields. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 642-651, 2009.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.

  12. Synthesis, characterization, and near-infrared luminescent properties of the ternary thulium complex covalently bonded to mesoporous MCM-41

    SciTech Connect

    Feng Jing; Song Shuyan; Xing Yan; Zhang Hongjie Li Zhefeng; Sun Lining; Guo Xianmin; Fan Weiqiang

    2009-03-15

    The crystal structure of a ternary Tm(DBM){sub 3}phen complex (DBM=dibenzoylmethane; phen=1, 10-phenanthroline) and the synthesis of hybrid mesoporous material in which the complex covalently bonded to mesoporous MCM-41 are reported. Crystal data: Tm(DBM){sub 3}phen C{sub 59}H{sub 47}N{sub 2}O{sub 7}Tm, monoclinic, P21/c, a=19.3216(12) A, b=10.6691(7) A, c=23.0165(15) A, {alpha}=90 deg., {beta}=91.6330(10) deg., {gamma}=90 deg., V=4742.8(5) A{sup 3}, Z=4. The properties of the Tm(DBM){sub 3}phen complex and the corresponding hybrid mesoporous material [Tm(DBM){sub 3}phen-MCM-41] have been studied. The results reveal that the Tm(DBM){sub 3}phen complex is successfully covalently bonded to MCM-41. Both Tm(DBM){sub 3}phen complex and Tm(DBM){sub 3}phen-MCM-41 display typical near-infrared (NIR) luminescence upon excitation at the maximum absorption of the ligands, which contributes to the efficient energy transfer from the ligands to the Tm{sup 3+} ion, an antenna effect. The full width at half maximum (FWHM) centered at 1474 nm in the emission spectrum of Tm(DBM){sub 3}phen-MCM-41 is 110 nm, which is the potential candidate of broadening amplification band from C band (1530-1560 nm) to S{sup +} band (1450-1480 nm) in optical area. - Graphical abstract: The crystal structure of Tm(DBM){sub 3}phen complex (DBM=dibenzoylmethane; phen=1, 10-phenanthroline). The complex is successfully covalently bonded to MCM-41 (Tm(DBM){sub 3}phen-MCM-41). After ligand-mediated excitation, the emission spectrum of Tm(DBM){sub 3}phen-MCM-41 shows the bands 802 and 1474 nm. The FWHM of the 1474-nm band for Tm(DBM){sub 3}phen-MCM-41 is 110 nm, such a broad spectrum enables a wide gain bandwidth for optical amplification.

  13. Infrared absorption spectroscopy of the weakly bonded CO-Cl2 complex

    NASA Astrophysics Data System (ADS)

    Bunte, Steven W.; Miller, Jason B.; Huang, Zhi-Song S.; Verdasco, Juan E.; Wittig, Curt; Beaudet, Robert A.

    1993-09-01

    High-resolution rovibrational absorption spectra of the weakly bonded CO-Cl2 complex have been recorded in the 2143/cm region by exciting the CO chromophore with a tunable diode laser. The spectra indicate that CO-Cl2 is linear and semirigid. The distance between the CO and Cl2 centers of mass is approximately 4.78 A. The orientation of CO is not determined experimentally. However, Cl2 appears to act as a classical sigma electron acceptor, while CO behaves like a weak Lewis base donating charge from the carbon side via the weakly antibonding sigma orbital, thereby raising the CO vibrational frequency.

  14. Comparison of Algorithms for Determination of Rotation Measure and Faraday Structure. I. 1100-1400 MHz

    NASA Astrophysics Data System (ADS)

    Sun, X. H.; Rudnick, L.; Akahori, Takuya; Anderson, C. S.; Bell, M. R.; Bray, J. D.; Farnes, J. S.; Ideguchi, S.; Kumazaki, K.; O'Brien, T.; O'Sullivan, S. P.; Scaife, A. M. M.; Stepanov, R.; Stil, J.; Takahashi, K.; van Weeren, R. J.; Wolleben, M.

    2015-02-01

    Faraday rotation measures (RMs) and more general Faraday structures are key parameters for studying cosmic magnetism and are also sensitive probes of faint ionized thermal gas. A definition of which derived quantities are required for various scientific studies is needed, as well as addressing the challenges in determining Faraday structures. A wide variety of algorithms has been proposed to reconstruct these structures. In preparation for the Polarization Sky Survey of the Universe's Magnetism (POSSUM) to be conducted with the Australian Square Kilometre Array Pathfinder and the ongoing Galactic Arecibo L-band Feeds Array Continuum Transit Survey (GALFACTS), we run a Faraday structure determination data challenge to benchmark the currently available algorithms, including Faraday synthesis (previously called RM synthesis in the literature), wavelet, compressive sampling, and QU-fitting. The input models include sources with one Faraday thin component, two Faraday thin components, and one Faraday thick component. The frequency set is similar to POSSUM/GALFACTS with a 300 MHz bandwidth from 1.1 to 1.4 GHz. We define three figures of merit motivated by the underlying science: (1) an average RM weighted by polarized intensity, R{{M}wtd}, (2) the separation Δφ of two Faraday components, and (3) the reduced chi-squared χ r2. Based on the current test data with a signal-to-noise ratio of about 32, we find the following. (1) When only one Faraday thin component is present, most methods perform as expected, with occasional failures where two components are incorrectly found. (2) For two Faraday thin components, QU-fitting routines perform the best, with errors close to the theoretical ones for R{{M}wtd} but with significantly higher errors for Δφ . All other methods, including standard Faraday synthesis, frequently identify only one component when Δφ is below or near the width of the Faraday point-spread function. (3) No methods as currently implemented work well for

  15. Comparison of algorithms for determination of rotation measure and Faraday structure. I. 1100–1400 MHz

    SciTech Connect

    Sun, X. H.; Akahori, Takuya; Anderson, C. S.; Farnes, J. S.; O’Sullivan, S. P.; Rudnick, L.; O’Brien, T.; Bell, M. R.; Bray, J. D.; Scaife, A. M. M.; Ideguchi, S.; Kumazaki, K.; Stepanov, R.; Stil, J.; Wolleben, M.; Takahashi, K.; Weeren, R. J. van E-mail: larry@umn.edu

    2015-02-01

    Faraday rotation measures (RMs) and more general Faraday structures are key parameters for studying cosmic magnetism and are also sensitive probes of faint ionized thermal gas. A definition of which derived quantities are required for various scientific studies is needed, as well as addressing the challenges in determining Faraday structures. A wide variety of algorithms has been proposed to reconstruct these structures. In preparation for the Polarization Sky Survey of the Universe's Magnetism (POSSUM) to be conducted with the Australian Square Kilometre Array Pathfinder and the ongoing Galactic Arecibo L-band Feeds Array Continuum Transit Survey (GALFACTS), we run a Faraday structure determination data challenge to benchmark the currently available algorithms, including Faraday synthesis (previously called RM synthesis in the literature), wavelet, compressive sampling, and QU-fitting. The input models include sources with one Faraday thin component, two Faraday thin components, and one Faraday thick component. The frequency set is similar to POSSUM/GALFACTS with a 300 MHz bandwidth from 1.1 to 1.4 GHz. We define three figures of merit motivated by the underlying science: (1) an average RM weighted by polarized intensity, RM{sub wtd}, (2) the separation Δϕ of two Faraday components, and (3) the reduced chi-squared χ{sub r}{sup 2}. Based on the current test data with a signal-to-noise ratio of about 32, we find the following. (1) When only one Faraday thin component is present, most methods perform as expected, with occasional failures where two components are incorrectly found. (2) For two Faraday thin components, QU-fitting routines perform the best, with errors close to the theoretical ones for RM{sub wtd} but with significantly higher errors for Δϕ. All other methods, including standard Faraday synthesis, frequently identify only one component when Δϕ is below or near the width of the Faraday point-spread function. (3) No methods as currently implemented

  16. Ultrafast magnetic vortex core switching driven by the topological inverse Faraday effect.

    PubMed

    Taguchi, Katsuhisa; Ohe, Jun-ichiro; Tatara, Gen

    2012-09-21

    We present a theoretical discovery of an unconventional mechanism of inverse Faraday effect which acts selectively on topological magnetic structures. The effect, topological inverse Faraday effect, is induced by the spin Berry's phase of the magnetic structure when a circularly polarized light is applied. Thus a spin-orbit interaction is not necessary unlike that in the conventional inverse Faraday effect. We demonstrate by numerical simulation that topological inverse Faraday effect realizes ultrafast switching of a magnetic vortex within a switching time of 150 ps without magnetic field.

  17. A novel Cs-(129)Xe atomic spin gyroscope with closed-loop Faraday modulation.

    PubMed

    Fang, Jiancheng; Wan, Shuangai; Qin, Jie; Zhang, Chen; Quan, Wei; Yuan, Heng; Dong, Haifeng

    2013-08-01

    We report a novel Cs-(129)Xe atomic spin gyroscope (ASG) with closed-loop Faraday modulation method. This ASG requires approximately 30 min to start-up and 110 °C to operate. A closed-loop Faraday modulation method for measurement of the optical rotation was used in this ASG. This method uses an additional Faraday modulator to suppress the laser intensity fluctuation and Faraday modulator thermal induced fluctuation. We theoretically and experimentally validate this method in the Cs-(129)Xe ASG and achieved a bias stability of approximately 3.25 °∕h.

  18. Pattern transition of two-dimensional Faraday waves at an extremely shallow depth

    NASA Astrophysics Data System (ADS)

    Li, XiaoChen; Li, XiaoMing; Liao, ShiJun

    2016-11-01

    In this paper, we experimentally investigate the pattern transition of two-dimensional Faraday waves at an extremely shallow depth in a Hele-Shaw cell. Several patterns of Faraday waves are observed, which have some significant differences in wave profile, wave height and wave length. It is found that, in a wide range of the forcing frequency f, there always exists a region of the acceleration amplitude A, in which there exist the so-called hysteretic jumps between different patterns of Faraday waves. All of these experimental observations could enrich our knowledges about the Faraday waves and would be helpful to the further theoretical studies on the related topic in future.

  19. Quantum Faraday effect in a double-dot Aharonov-Bohm loop

    NASA Astrophysics Data System (ADS)

    Kang, Kicheon

    2012-07-01

    We investigate the role of Faraday's law of induction manifested in the quantum state of Aharonov-Bohm (AB) loops. In particular, a flux-switching experiment is proposed for a double-dot AB loop to verify the phase shift induced by Faraday's law. The induced Faraday phase is shown to be geometric and nontopological. This study demonstrates that the relation between the local phases of a ring at different fluxes is not arbitrary but is instead determined by Faraday's inductive law, which is in contrast to the arbitrary local phase of an AB loop for a given flux.

  20. Infrared and visible emission from organic electroluminescent devices based on praseodymium complex

    NASA Astrophysics Data System (ADS)

    Hong, Ziruo; Liang, Chunjun; Li, Ruigang; Zang, Faxin; Fan, Di; Li, Wenlian; Hung, L. S.; Lee, S. T.

    2001-09-01

    Praseodymium(dibenzoylmethanato)3(bathophenanthroline) [Pr(DBM)3bath] was employed as an emitting and electron transport layer, and N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1, 1'-biphenyl-4,4'-diamine (TPD) as a hole transport layer in organic electroluminescent (EL) devices. Bilayer device TPD/Pr(DBM)3bath and trilayer devices TPD/TPD:Pr(DBM)3bath/Pr(DBM)3bath with a different ratio of TPD to the Pr-complex were fabricated. Emission bands at 608 nm (1D2→3H6), 890 nm (1D2→3F2), 1015 nm (1D2→3F3), 1065 nm (1D2→3F4) and 1550 nm (1D2→1G4) originating from the internal f-f transitions of a Pr3+ ion were observed from EL devices using both bilayer and trilayer structures. Decreasing the ratio of TPD to the Pr-complex, the emission of the 1D2→3H6 transition was promoted and that from the exciplex suppressed, which was explained in terms of energy transfer from the ligand to the central ion.

  1. Infrared Laser Stark Spectroscopy of the OH\\cdot\\cdot\\cdotCH3OH Complex Isolated in Superfluid Helium Droplets

    NASA Astrophysics Data System (ADS)

    Leavitt, Christopher M.; Brice, Joseph T.; Douberly, Gary E.; Hernandez, Federico J.; Pino, Gustavo A.

    2015-06-01

    The elimination of volatile organic compounds (VOCs) from the atmosphere is initiated by reactions with OH, NO3 and O3. For oxygenated VOCs, such as alcohols, ketones, ethers, etc., reactions occur nearly exclusively with the hydroxyl radical. Furthermore, the potential energy surfaces associated with reactions between OH and oxygenated VOCs generally feature a pre-reactive complex, stabilized by hydrogen bonding, which results in rate constants that exhibit large negative temperature dependencies. This was explicitly demonstrated recently for the OH + methanol (MeOH) reaction, where the rate constant increased by nearly two orders of magnitude when the temperature decreased from 200 K to below 70 K, highlighting the potential impact of this reaction in the interstellar medium (ISM). In this study, we trap this postulated pre-reactive complex formed between OH and MeOH using He nanodroplet isolation (HENDI) techniques, and probe this species using a combination of mass spectrometry and infrared laser Stark spectroscopy. Atkinson, R.; Arey, J., Chem. Rev. 2003, 103, 4605-4638. Mellouki, A.; Le Bras, G.; Sidebottom, H., Chem. Rev. 2003, 103, 5077-5096. Smith, I. W. M.; Ravishankara, A. R., J. Phys. Chem. A 2002, 106, 4798-4807 Shannon, R. J.; Blitz, M. A.; Goddard, A.; Heard, D. E., Nat. Chem. 2013, 5, 745-749. Martin, J. C. G.; Caravan, R. L.; Blitz, M. A.; Heard, D. E.; Plane, J. M. C., J. Phys. Chem. A 2014, 118, 2693-2701.

  2. Near-infrared spectroscopy and anharmonic theory of the H2O(+)Ar1,2 cation complexes.

    PubMed

    Wagner, J Philipp; McDonald, David C; Duncan, Michael A

    2017-09-14

    Weakly bound complexes of the water radical cation with argon (H2O(+)Arn, n = 1,2) were generated by an electrical discharge/supersonic expansion and probed with mid- and near-infrared photodissociation spectroscopy in the 2050-4550 and 4850-7350 cm(-1) regions. To elucidate these spectra, these complexes were studied computationally at the CCSD(T) level including anharmonicity with the VPT2 method. The comparison between experiment and predicted spectra demonstrates that the VPT2 method is adequate to capture most of the vibrational band positions and their intensities. In addition to the fundamentals, overtones of the symmetric and the asymmetric water stretches and their combination were detected. Additional bands were assigned to combinations of the overtone of the bound O-H stretch with multiple excitation levels of the intermolecular Ar-H stretch. H2O(+)Ar2 could not be dissociated in the higher frequency region (4850-7350 cm(-1)).

  3. Infrared Spectra of Novel NgBeSO2 Complexes (Ng = Ne, Ar, Kr, Xe) in Low Temperature Matrixes.

    PubMed

    Yu, Wenjie; Liu, Xing; Xu, Bing; Xing, Xiaopeng; Wang, Xuefeng

    2016-11-03

    The novel noble-gas complexes NgBeSO2 (Ng = Ne, Ar, Kr, Xe) have been prepared in the laser-evaporated beryllium atom reactions with SO2 in low-temperature matrixes. Doped with heavier noble gas, the guest (Ar, Kr, Xe) atom can substitute neon to form more stable complex. Infrared spectroscopy and theoretical calculations are used to confirm the band assignment. The dissociation energies are calculated at 0.9, 4.0, 4.7, and 6.0 kcal/mol for NeBeSO2, ArBeSO2, KrBeSO2, and XeBeSO2, respectively, at the CCSD(T) level. Quantum chemical calculations demonstrate that the Ng-Be bonds in NgBeSO2 could be formed by the combination of electron-donation and ion-induced dipole interactions. The Wiberg bond index (WBI) values of Ng-Be bonds and LOL (localized orbital locator) profile indicate that the Ng-Be bond exhibits a gradual increase in covalent character along Ne to Xe.

  4. Cyclotron resonance and Faraday rotation in topological insulator (Bi,Sb)2 Te3

    NASA Astrophysics Data System (ADS)

    Shao, Yinming; Post, Kirk; Wu, Jhih-Sheng; Richardella, Anthony; Lee, Joon Sue; Fogler, Michael; Samarth, Nitin; Basov, Dimitri

    Using magneto-optical spectroscopy, we have explored the complex electronic structure of (Bi,Sb)2 Te3 (BST) film. From the magneto-optical transmission spectra, we extracted the cyclotron resonance (CR) energy, and subsequently measured the broadband Faraday rotation spectra (FR). From these complementary FR-CR datasets, we were able to identify the conducting channels associated with the topological surface states of the film at the interface with the substrate and with the amorphous capping layer on top of the film. According to the FR data the two surfaces are dominated by carriers of opposite sign, in accord with earlier transport measurements. These results elucidate the origin of the zero-field optical response, observed previously, and give direct evidence of significant SS contribution using a bulk sensitive probe.

  5. Conversion of the spin state of the manganese complex in photosystem II induced by near-infrared light.

    PubMed

    Boussac, A; Girerd, J J; Rutherford, A W

    1996-06-04

    The manganese complex (Mn4) which is responsible for water oxidation in photosystem II is EPR detectable in the S2 state, one of the five redox states of the enzyme cycle. The S2 state is observable at 10 K either as a multiline signal (spin 1/2) or as a signal at g = 4.1 (spin 3/2 or spin 5/2). It is shown here that at around 150 K the state responsible for the multiline signal is converted to that responsible for the g = 4.1 signal upon the absorption of infrared light. This conversion is fully reversible at 200 K. The action spectrum of this conversion has its maximum at 820 nm (12 200 cm-1) and is similar to the intervalence charge transfer band in di-mu-oxo-(MnIIIMnIV) model systems. It is suggested that the conversion of the multiline signal to the g = 4.1 signal results from absorption of infrared light by the Mn cluster itself, resulting in electron transfer from MnIII to MnIV. The g = 4.1 signal is thus proposed to arise from a state which differs from that which gives rise to the multiline signal only in terms of this change in its valence distribution. The near-infrared light effect was observed in the S2 state of Sr(2+)-reconstituted photosystem II and in Ca(2+)-depleted, EGTA (or citrate-)-treated photosystem II but not in ammonia-treated photosystem II. Earlier results in the literature which showed that the g = 4.1 state was preferentially formed by illumination at 130 K are reinterpreted as being the result of two photochemical events: the first being photosynthetic charge separation resulting in an S2 state which gives rise to the multiline signal and the second being the conversion of this state to the g = 4.1 state due to the simultaneous and inadvertent presence of 820 nm light in the broad-band illumination given. There is therefore no reason to consider the state responsible for the g = 4.1 signal as a precursor of that which gives rise to the multiline signal.

  6. A Submillimetre Study of Massive Star Formation Within the W51 Complex and Infrared Dark Clouds

    NASA Astrophysics Data System (ADS)

    Parsons, Harriet Alice Louise

    Despite its importance the fundamental question of how massive stars form remains unanswered, with improvements to both models and observations having crucial roles to play. To quote Bate et al. (2003) computational models of star formation are limited because "conditions in molecular clouds are not sufficiently well understood to be able to select a representative sample of cloud cores for the initial conditions". It is this notion that motivates the study of the environments within Giant Molecular Clouds (GMCs) and Infrared Dark Clouds (IRDCs), known sites of massive star formation, at the clump and core level. By studying large populations of these objects, it is possible to make conclusions based on global properties. With this in mind I study the dense molecular clumps within one of the most massive GMCs in the Galaxy: the W51 GMC. New observations of the W51 GMC in the 12CO, 13CO and C18O (3-2) transitions using the HARP instrument on the JCMT are presented. With the help of the clump finding algorithm CLUMPFIND a total of 1575 dense clumps are identified of which 1130 are associated with the W51 GMC, yielding a dense mass reservoir of 1.5 × 10^5 M contained within these clumps. Of these clumps only 1% by number are found to be super-critical, yielding a super-critical clump formation efficiency of 0.5%, below current SFE estimates of the region. This indicates star formation within the W51 GMC will diminish over time although evidence from the first search for molecular outflows presents the W51 GMC in an active light with a lower limit of 14 outflows. The distribution of the outflows within the region searched found them concentrated towards the W51A region. Having much smaller sizes and masses, obtaining global properties of clumps and cores within IRDCs required studying a large sample of these objects. To do this pre-existing data from the SCUBA Legacy Catalogue was utilised to study IRDCs within a catalogues based on 8 μm data. This data identified

  7. Sensitized near-infrared emission from ytterbium(III) via direct energy transfer from iridium(III) in a heterometallic neutral complex.

    PubMed

    Mehlstäubl, Marita; Kottas, Gregg S; Colella, Silvia; De Cola, Luisa

    2008-05-14

    A tetrametallic iridium-ytterbium complex has been synthesised that shows sensitized near-infrared emission (lambda(max) = 976 nm) upon excitation of the iridium unit in the visible region (400 nm) due to efficient energy transfer from the iridium units to the Yb(III) ion. The iridium phosphorescence is quenched nearly quantitatively while the ytterbium ion emits brightly in the NIR.

  8. Detection of complex formation and determination of intermolecular geometry through electrical anharmonic coupling of molecular vibrations using electron-vibration-vibration two-dimensional infrared spectroscopy.

    PubMed

    Guo, Rui; Fournier, Frederic; Donaldson, Paul M; Gardner, Elizabeth M; Gould, Ian R; Klug, David R

    2009-10-14

    Electrical interactions between molecular vibrations can be non-linear and thereby produce intermolecular coupling even in the absence of a chemical bond. We use this fact to detect the formation of an intermolecular complex using electron-vibration-vibration two-dimensional infrared spectroscopy (EVV 2DIR) and also to determine the distance and angle between the two molecular species.

  9. Evaluating preservation methods for identifying Anopheles gambiae s.s. and Anopheles arabiensis complex mosquitoes species using near infra-red spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Near infra-red spectroscopy (NIRS) has been successfully used on fresh and RNAlater® preserved Anopheles gambiae complex to identify sibling species and age. No preservation methods other than RNAlater® have been tested to preserve mosquitoes for species identification using NIRS. However, RNAlater®...

  10. Fourier-transform infrared spectroscopic studies on avidin secondary structure and complexation with biotin and biotin-lipid assemblies.

    PubMed Central

    Swamy, M J; Heimburg, T; Marsh, D

    1996-01-01

    Fourier-transform infrared studies have been carried out to investigate the secondary structure and thermal stability of hen egg white avidin and its complexes with biotin and with a biotinylated lipid derivative, N-biotinyl dimyristoyl phosphatidylethanolamine (DMBPE) in aqueous dispersion. Analysis of the amide I stretching band of avidin yielded a secondary structural content composed of approximately 66% beta-sheet and extended structures, with the remainder being attributed to disordered structure and beta-turns. Binding of biotin or specific association with the biotinylated lipid DMBPE did not result in any appreciable changes in the secondary structure content of the protein, but a change in hydrogen bond stability of the beta-sheet or extended chain regions was indicated. The latter effect was enhanced by surface interactions in the case of the biotin-lipid assemblies, as was demonstrated by electrostatic binding to a nonspecific negatively charged lipid. Difference spectra of the bound biotin implicated a direct involvement of the ureido moiety in the ligand interaction that was consistent with hydrogen bonding to amino acid residues in the avidin protein. It was found that complexation with avidin leads to a decrease in bond length of the biotin ureido carbonyl group that is consistent with a reduction of sp3 character of the C-O bond when it is hydrogen bonded to the protein. Studies of the temperature dependence of the spectra revealed that for avidin alone the secondary structure was unaltered up to approximately 75 degrees C, above which the protein undergoes a highly cooperative transition to an unfolded state with concomitant loss of ordered secondary structure. The complexes of avidin with both biotin and membrane-bound DMBPE lipid assemblies display a large increase in thermal stability compared with the native protein. PMID:8842222

  11. Fourier-transform infrared spectroscopic studies on avidin secondary structure and complexation with biotin and biotin-lipid assemblies.

    PubMed

    Swamy, M J; Heimburg, T; Marsh, D

    1996-08-01

    Fourier-transform infrared studies have been carried out to investigate the secondary structure and thermal stability of hen egg white avidin and its complexes with biotin and with a biotinylated lipid derivative, N-biotinyl dimyristoyl phosphatidylethanolamine (DMBPE) in aqueous dispersion. Analysis of the amide I stretching band of avidin yielded a secondary structural content composed of approximately 66% beta-sheet and extended structures, with the remainder being attributed to disordered structure and beta-turns. Binding of biotin or specific association with the biotinylated lipid DMBPE did not result in any appreciable changes in the secondary structure content of the protein, but a change in hydrogen bond stability of the beta-sheet or extended chain regions was indicated. The latter effect was enhanced by surface interactions in the case of the biotin-lipid assemblies, as was demonstrated by electrostatic binding to a nonspecific negatively charged lipid. Difference spectra of the bound biotin implicated a direct involvement of the ureido moiety in the ligand interaction that was consistent with hydrogen bonding to amino acid residues in the avidin protein. It was found that complexation with avidin leads to a decrease in bond length of the biotin ureido carbonyl group that is consistent with a reduction of sp3 character of the C-O bond when it is hydrogen bonded to the protein. Studies of the temperature dependence of the spectra revealed that for avidin alone the secondary structure was unaltered up to approximately 75 degrees C, above which the protein undergoes a highly cooperative transition to an unfolded state with concomitant loss of ordered secondary structure. The complexes of avidin with both biotin and membrane-bound DMBPE lipid assemblies display a large increase in thermal stability compared with the native protein.

  12. Infrared Multiple Photon Dissociation Spectroscopy of a Gas-Phase Oxo-Molybdenum Complex with 1,2-Dithiolene Ligands

    PubMed Central

    2015-01-01

    Electrospray ionization (ESI) in the negative ion mode was used to create anionic, gas-phase oxo-molybdenum complexes with dithiolene ligands. By varying ESI and ion transfer conditions, both doubly and singly charged forms of the complex, with identical formulas, could be observed. Collision-induced dissociation (CID) of the dianion generated exclusively the monoanion, while fragmentation of the monoanion involved decomposition of the dithiolene ligands. The intrinsic structure of the monoanion and the dianion were determined by using wavelength-selective infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory calculations. The IRMPD spectrum for the dianion exhibits absorptions that can be assigned to (ligand) C=C, C–S, C—C≡N, and Mo=O stretches. Comparison of the IRMPD spectrum to spectra predicted for various possible conformations allows assignment of a pseudo square pyramidal structure with C2v symmetry, equatorial coordination of MoO2+ by the S atoms of the dithiolene ligands, and a singlet spin state. A single absorption was observed for the oxidized complex. When the same scaling factor employed for the dianion is used for the oxidized version, theoretical spectra suggest that the absorption is the Mo=O stretch for a distorted square pyramidal structure and doublet spin state. A predicted change in conformation upon oxidation of the dianion is consistent with a proposed bonding scheme for the bent-metallocene dithiolene compounds [Lauher, J. W.; Hoffmann, R. J. Am. Chem. Soc.1976, 98, 1729−1742], where a large folding of the dithiolene moiety along the S···S vector is dependent on the occupancy of the in-plane metal d-orbital. PMID:24988369

  13. Feasibility of diffuse reflectance infrared Fourier spectroscopy (DRIFTS) to quantify iron-cyanide (Fe-CN) complexes in soil

    NASA Astrophysics Data System (ADS)

    Sut-Lohmann, Magdalena; Raab, Thomas

    2017-04-01

    Contaminated sites create a significant risk to human health, by poisoning drinking water, soil, air and as a consequence food. Continuous release of persistent iron-cyanide (Fe-CN) complexes from various industrial sources poses a high hazard to the environment and indicates the necessity to analyze considerable amount of samples. At the present time quantitative determination of Fe-CN concentration in soil usually requires a time consuming two step process: digestion of the sample (e.g., micro distillation system) and its analytical detection performed, e.g., by automated spectrophotometrical flow injection analysis (FIA). In order to determine the feasibility of diffuse reflectance infrared Fourier spectroscopy (DRIFTS) to quantify the Fe-CN complexes in soil matrix, 42 soil samples were collected (8 to 12.520 mg kg-1CN) indicating single symmetrical CN band in the range 2092 - 2084 cm-1. Partial least squares (PLS) calibration-validation model revealed IR response to CNtot exceeding 1268 mg kg-1 (limit of detection, LOD). Subsequently, leave-one-out cross-validation (LOO-CV) was performed on soil samples containing low CNtot (<900 mg kg-1), which improved the sensitivity of the model by reducing the LOD to 154 mg kg-1. Finally, the LOO-CV conducted on the samples with CNtot >900 mg kg-1 resulted in LOD equal to 3494 mg kg-1. Our results indicate that spectroscopic data in combination with PLS statistics can efficiently be used to predict Fe-CN concentrations in soil. We conclude that the protocol applied in this study can strongly reduce the time and costs essential for the spatial and vertical screening of the site affected by complexed Fe-CN.

  14. Probing broken symmetry states in cuprate superconductors with polarization-sensitive infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Mukherjee, Alok; Arik, Mumtaz Murat; Seo, Jungryeol; Cerne, John; Zhang, Hao; Xu, Ke Jun; Wei, John Y. T.; Armitage, N. P.; Kirzhner, T.; Koren, G.

    The nature of the pseudogap state in high-temperature superconducting (HTS) cuprates has drawn a lot of attention in the past two decades. A fundamental question is whether the pseudogap is a distinct phase with its own broken symmetries. Recent optical studies in the near-IR (800 meV) and THz (2-6 meV) ranges have observed symmetry breaking in the pseudogap state of HTS cuprates, suggesting that the pseudogap is a distinct phase. To probe the spectral character of this broken symmetry, we have performed infrared/visible Faraday and Kerr effect measurements at zero magnetic field and various temperatures on a series of HTS cuprate thin films, grown epitaxially by pulsed laser-ablated deposition. We will present and discuss our data, primarily complex Faraday/Kerr angle as a function of energy (0.1-3 eV), temperature (10-300K) and sample orientation with respect to the incident light polarization. This work supported by NSF-DMR1410599, NSERC, CFI-OIT and the Canadian Institute for Advanced Research.

  15. A precision control method for plasma electron density and Faraday rotation angle measurement on HL-2A

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wu, Tongyu; Ding, Baogang; Li, Yonggao; Zhou, Yan; Yin, Zejie

    2017-07-01

    The precision of plasma electron density and Faraday rotation angle measurement is a key indicator for far-infrared laser interferometer/polarimeter plasma diagnosis. To improve the precision, a new multi-channel high signal-to-noise ratio HCOOH interferometer/polarimeter has been developed on the HL-2A tokamak. It has a higher level requirement for phase demodulation precision. This paper introduces an improved real-time fast Fourier transform algorithm based on the field programmable gate array, which significantly improves the precision. We also apply a real-time error monitoring module (REMM) and a stable error inhibiting module (SEIM) for precision control to deal with the weak signal. We test the interferometer/polarimeter system with this improved precision control method in plasma discharge experiments and simulation experiments. The experimental results confirm that the plasma electron density precision is better than 1/3600 fringe and the Faraday rotation angle measurement precision is better than 1/900 fringe, while the temporal resolution is 80 ns. This performance can fully meet the requirements of HL-2A.

  16. Single-trial classification of motor imagery differing in task complexity: a functional near-infrared spectroscopy study

    PubMed Central

    2011-01-01

    Background For brain computer interfaces (BCIs), which may be valuable in neurorehabilitation, brain signals derived from mental activation can be monitored by non-invasive methods, such as functional near-infrared spectroscopy (fNIRS). Single-trial classification is important for this purpose and this was the aim of the presented study. In particular, we aimed to investigate a combined approach: 1) offline single-trial classification of brain signals derived from a novel wireless fNIRS instrument; 2) to use motor imagery (MI) as mental task thereby discriminating between MI signals in response to different tasks complexities, i.e. simple and complex MI tasks. Methods 12 subjects were asked to imagine either a simple finger-tapping task using their right thumb or a complex sequential finger-tapping task using all fingers of their right hand. fNIRS was recorded over secondary motor areas of the contralateral hemisphere. Using Fisher's linear discriminant analysis (FLDA) and cross validation, we selected for each subject a best-performing feature combination consisting of 1) one out of three channel, 2) an analysis time interval ranging from 5-15 s after stimulation onset and 3) up to four Δ[O2Hb] signal features (Δ[O2Hb] mean signal amplitudes, variance, skewness and kurtosis). Results The results of our single-trial classification showed that using the simple combination set of channels, time intervals and up to four Δ[O2Hb] signal features comprising Δ[O2Hb] mean signal amplitudes, variance, skewness and kurtosis, it was possible to discriminate single-trials of MI tasks differing in complexity, i.e. simple versus complex tasks (inter-task paired t-test p ≤ 0.001), over secondary motor areas with an average classification accuracy of 81%. Conclusions Although the classification accuracies look promising they are nevertheless subject of considerable subject-to-subject variability. In the discussion we address each of these aspects, their limitations for

  17. Herschel far-infrared observations of the Carina Nebula complex. II. The embedded young stellar and protostellar population

    NASA Astrophysics Data System (ADS)

    Gaczkowski, B.; Preibisch, T.; Ratzka, T.; Roccatagliata, V.; Ohlendorf, H.; Zinnecker, H.

    2013-01-01

    Context. The Carina Nebula represents one of the largest and most active star forming regions known in our Galaxy. It contains numerous very massive (M ≳ 40 M⊙) stars that strongly affect the surrounding clouds by their ionizing radiation and stellar winds. Aims: Our recently obtained Herschel PACS and SPIRE far-infrared maps cover the full area (≈8.7 deg2) of the Carina Nebula complex (CNC) and reveal the population of deeply embedded young stellar objects (YSOs), most of which are not yet visible in the mid- or near-infrared. Methods: We study the properties of the 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands. For those objects that can be identified with apparently single Spitzer counterparts, we use radiative transfer models to derive information about the basic stellar and circumstellar parameters. Results: We find that about 75% of the Herschel-detected YSOs are Class 0 protostars. The luminosities of the Herschel-detected YSOs with SED fits are restricted to values of ≤5400 L⊙, their masses (estimated from the radiative transfer modeling) range from ≈1 M⊙ to ≈10 M⊙. Taking the observational limits into account and extrapolating the observed number of Herschel-detected protostars over the stellar initial mass function suggest that the star formation rate of the CNC is ~0.017 M⊙/year. The spatial distribution of the Herschel YSO candidates is highly inhomogeneous and does not follow the distribution of cloud mass. Rather, most Herschel YSO candidates are found at the irradiated edges of clouds and pillars. The far-infrared fluxes of the famous object η Car are about a factor of two lower than expected from observations with the Infrared Space Observatory obtained 15 years ago; this difference may be a consequence of dynamical changes in the circumstellar dust in the Homunculus Nebula around η Car. Conclusions: The currently ongoing star formation process forms only low

  18. Michael Faraday, 30,000 Teenagers and Climate Change

    NASA Astrophysics Data System (ADS)

    Giles, K. A.; Wingham, D. J.

    2006-12-01

    One of the objectives of IPY is to engage the awareness, interest and understanding of schoolchildren, the general public and decision-makers worldwide in the purpose and value of polar research and monitoring. Between January and March 2006 I co-presented the Faraday Lecture, run by the Institution of Engineering Technology, which aims to interest the public, and young people in particular, in science and engineering. The topic of the lecture this year was climate change and the technologies that have the potential to reduce our carbon dioxide emissions. As a research fellow at the Centre for Polar Observation and Modelling, University College London, I was able to use my knowledge of the polar regions to help explain the fundamentals of human induced climate change, from using ice cores for paleoclimate studies to what would happen if Greenland melted. The lecture was attended by 30,000 people, mainly aged between 14 to 16, at theatres across the UK and Asia, as well as broadcast on the web to North America and Europe. While the lecture was generally well received, it was apparent that there are misconceptions about the roles of scientists and engineers and a limited understanding of the polar regions and why they are important. The Faraday Lecture is a useful example of a large-scale vehicle for public understanding of science, and for assessing what works and what does not work when addressing young audiences. We consider the lessons learnt from the Faraday lectures in terms of bringing the IPY activities to the attention of the next generation of polar scientists using not only lectures, but a also wider variety of multi-media techniques.

  19. Faraday rotation spectrum of magneto-optical nanoparticle aggregates

    NASA Astrophysics Data System (ADS)

    Sadrara, Mahdiyeh; Miri, MirFaez

    2017-09-01

    The interaction of light with a cluster of gyrotropic spherical particles is studied in view of a miniaturized Faraday rotator. The electromagnetic fields are expanded in terms of the vector multipole fields and the expansion of the scattered field is related to that of the incident field. An incident linearly polarized light with polarization azimuth ψ becomes elliptically polarized upon scattering from the cluster. The polarization azimuth rotation and ellipticity angle variation are almost sinusoidal functions of 2 ψ . With planar disordered clusters of bismuth-substituted yttrium iron garnet nanoparticles of radius 50 nm, polarization rotations about ±4∘ are achievable.

  20. A model for Faraday pilot waves over variable topography

    NASA Astrophysics Data System (ADS)

    Faria, Luiz M.

    2017-01-01

    Couder and Fort discovered that droplets walking on a vibrating bath possess certain features previously thought to be exclusive to quantum systems. These millimetric droplets synchronize with their Faraday wavefield, creating a macroscopic pilot-wave system. In this paper we exploit the fact that the waves generated are nearly monochromatic and propose a hydrodynamic model capable of quantitatively capturing the interaction between bouncing drops and a variable topography. We show that our reduced model is able to reproduce some important experiments involving the drop-topography interaction, such as non-specular reflection and single-slit diffraction.

  1. Response function of modulated grid Faraday cup plasma instruments

    NASA Technical Reports Server (NTRS)

    Barnett, A.; Olbert, S.

    1986-01-01

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager plasma science experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. Multisensor analysis of solar wind data indicates that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  2. Faraday rotation in bilayer graphene-based integrated microcavity.

    PubMed

    Da, Hai-Xia; Yan, Xiao-Hong

    2016-01-01

    Bernal-stacked bilayer graphene has rich ground states with various broken symmetries, allowing the existence of magneto-optical (MO) effects even in the absence of an external magnetic field. Here we report controllable Faraday rotation (FR) of bilayer graphene induced by electrostatic gate voltage, whose value is 10 times smaller than the case of single layer graphene with a magnetic field. A proposed bilayer graphene-based microcavity configuration enables the enhanced FR angle due to the large localized electromagnetic field. Our results offer unique opportunities to apply bilayer graphene for MO devices.

  3. Faraday rotator based on TSAG crystal with <001> orientation.

    PubMed

    Yasuhara, Ryo; Snetkov, Ilya; Starobor, Aleksey; Mironov, Evgeniy; Palashov, Oleg

    2016-07-11

    A Faraday isolator (FI) for high-power lasers with kilowatt-level average power and 1-µm wavelength was demonstrated using a terbium scandium aluminum garnet (TSAG) with its crystal axis aligned in the <001> direction. Furthermore, no compensation scheme for thermally induced depolarization in a magnetic field was used. An isolation ratio of 35.4 dB (depolarization ratio γ of 2.9 × 10-4) was experimentally observed at a maximum laser power of 1470 W. This result for room-temperature FIs is the best reported, and provides a simple, practical solution for achieving optical isolation in high-power laser systems.

  4. RF-sheath assessment of ICRF Faraday Screens

    SciTech Connect

    Colas, L.

    2007-09-28

    The line-integrated parallel RF electric field {delta}V{sub RF} is studied on 'long field lines' radially in front of an ICRF antenna closed by a Faraday screen (FS). Several issues are addressed analytically and numerically. To what extent is a FS necessary to shield {delta}V{sub RF} in presence of magnetized plasma, depending on strap phasing? How efficient is it as a function of FS misalignment on tilted magnetic field? Can a FS attenuate {delta}V{sub RF} produced on antenna frame?.

  5. Faraday cup: absolute dosimetry for ELIMED beam line

    NASA Astrophysics Data System (ADS)

    Leanza, R.; Romano, F.; Scuderi, V.; Amico, A. G.; Cuttone, G.; Larosa, G.; Margarone, D.; Milluzzo, G.; Petringa, G.; Pipek, J.; Schillaci, F.; Cirrone, G. A. P.

    2017-03-01

    The scientific community has shown a growing interest towards multidisciplinary applications of laser-driven beams. In this framework, the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline will be the first transport beamline dedicated to the medical and multidisciplinary studies with laser-accelerated ion beams. Detectors for dosimetry represent one of key-element of the ELIMED beamline, allowing a dose delivering with good result as required in the clinical applications. In this contribution, a Faraday Cup for absolute dosimetry, designed and realized at INFN-LNS, is described.

  6. A model for Faraday pilot-waves over variable topography

    NASA Astrophysics Data System (ADS)

    Faria, Luiz

    2016-11-01

    In 2005 Yves Couder and co-workers discovered that droplets walking on a vibrating bath posses certain features previously thought to be exclusive to quantum systems. These millimetric droplets synchronize with their Faraday wavefield, creating a macroscopic pilot-wave system. In this talk we exploit the fact that the waves generated are nearly monochromatic and propose a hydrodynamic model capable of capturing the interaction between bouncing drops and a variable topography. We show that our model is able to reproduce some important experiments involving the drop-topography interaction, such as non-specular reflection and single-slit diffraction.

  7. Reactions of Highly Uniform Zeolite H-Supported Rhodium Complexes: Transient Characterization by Infrared and X-ray Absorption Spectroscopies

    SciTech Connect

    Ogino, I.; Gates, B

    2010-01-01

    A zeolite H-{beta}-supported mononuclear rhodium diethene complex (Rh(C{sub 2}H{sub 4}){sub 2}{l_brace}O{sub 2}Al{r_brace}, where the braces indicate a part of the zeolite) was formed by the reaction of Rh(acac)({eta}{sub 2}-C{sub 2}H{sub 4}){sub 2} (acac = acetylacetonate, C{sub 5}H{sub 7}O{sub 2}{sup -}) with the zeolite. Transient characterization of the sample by X-ray absorption near edge structure (XANES) and infrared (IR) spectroscopies (combined with mass spectrometry of the effluent gas) while the sample was in contact with flowing CO indicates a simple stoichiometric conversion of the supported metal complex into another species, identified by the spectra as the zeolite-supported rhodium gem-dicarbonyl (Rh(CO){sub 2}{l_brace}O{sub 2}Al{r_brace}). The sharpness of the v{sub CO} bands in the IR spectrum indicates a high degree of uniformity of the supported rhodium gem-dicarbonyl, and isosbestic points in the XANES spectra as the transformation was occurring imply that the rhodium diethene complex was also highly uniform. Spectra similarly show that treatment of the supported rhodium gem-dicarbonyl with flowing C{sub 2}H{sub 4} resulted in another stoichiometrically simple transformation, giving a species suggested to be Rh(C{sub 2}H{sub 4})(CO){sub 2}{l_brace}O{sub 2}Al{r_brace}. The intermediate was ultimately transformed when the sample was purged with helium into another highly uniform supported species, inferred on the basis of IR spectra to be Rh(C{sub 2}H{sub 4})(CO){l_brace}O{sub 2}Al{r_brace}. Extended X-ray absorption fine structure spectra characterizing the supported rhodium diethene complex and the species formed from it show how the Rh-O bond distance at the Rh-support interface varied in response to the changes in the ligands bonded to the rhodium.

  8. A Left-Hand Rule for Faraday's Law

    ERIC Educational Resources Information Center

    Salu, Yehuda

    2014-01-01

    A left-hand rule for Faraday's law is presented here. This rule provides a simple and quick way of finding directional relationships between variables of Faraday's law without using Lenz's rule.

  9. Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory

    ERIC Educational Resources Information Center

    Tweney, Ryan D.

    2011-01-01

    James Clerk Maxwell "translated" Michael Faraday's experimentally-based field theory into the mathematical representation now known as "Maxwell's Equations." Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other…

  10. Faraday cup with nanosecond response and adjustable impedance for fast electron beam characterization.

    PubMed

    Hu, Jing; Rovey, Joshua L

    2011-07-01

    A movable Faraday cup design with simple structure and adjustable impedance is described in this work. This Faraday cup has external adjustable shunt resistance for self-biased measurement setup and 50 Ω characteristic impedance to match with 50 Ω standard BNC coaxial cable and vacuum feedthroughs for nanosecond-level pulse signal measurements. Adjustable shunt resistance allows self-biased measurements to be quickly acquired to determine the electron energy distribution function. The performance of the Faraday cup is validated by tests of response time and amplitude of output signal. When compared with a reference source, the percent difference of the Faraday cup signal fall time is less than 10% for fall times greater than 10 ns. The percent difference of the Faraday cup signal pulse width is below 6.7% for pulse widths greater than 10 ns. A pseudospark-generated electron beam is used to compare the amplitude of the Faraday cup signal with a calibrated F-70 commercial current transformer. The error of the Faraday cup output amplitude is below 10% for the 4-14 kV tested pseudospark voltages. The main benefit of this Faraday cup is demonstrated by adjusting the external shunt resistance and performing the self-biased method for obtaining the electron energy distribution function. Results from a 4 kV pseudospark discharge indicate a "double-humped" energy distribution.

  11. Nonreciprocal plasmonics enables giant enhancement of thin-film Faraday rotation.

    PubMed

    Chin, Jessie Yao; Steinle, Tobias; Wehlus, Thomas; Dregely, Daniel; Weiss, Thomas; Belotelov, Vladimir I; Stritzker, Bernd; Giessen, Harald

    2013-01-01

    Light propagation is usually reciprocal. However, a static magnetic field along the propagation direction can break the time-reversal symmetry in the presence of magneto-optical materials. The Faraday effect in magneto-optical materials rotates the polarization plane of light, and when light travels backward the polarization is further rotated. This is applied in optical isolators, which are of crucial importance in optical systems. Faraday isolators are typically bulky due to the weak Faraday effect of available magneto-optical materials. The growing research endeavour in integrated optics demands thin-film Faraday rotators and enhancement of the Faraday effect. Here, we report significant enhancement of Faraday rotation by hybridizing plasmonics with magneto-optics. By fabricating plasmonic nanostructures on laser-deposited magneto-optical thin films, Faraday rotation is enhanced by one order of magnitude in our experiment, while high transparency is maintained. We elucidate the enhanced Faraday effect by the interplay between plasmons and different photonic waveguide modes in our system.

  12. A Left-Hand Rule for Faraday's Law

    ERIC Educational Resources Information Center

    Salu, Yehuda

    2014-01-01

    A left-hand rule for Faraday's law is presented here. This rule provides a simple and quick way of finding directional relationships between variables of Faraday's law without using Lenz's rule.

  13. Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory

    ERIC Educational Resources Information Center

    Tweney, Ryan D.

    2011-01-01

    James Clerk Maxwell "translated" Michael Faraday's experimentally-based field theory into the mathematical representation now known as "Maxwell's Equations." Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other…

  14. Polarization-induced phase noise in fiber optic Michelson interferometer with Faraday rotator mirrors

    NASA Astrophysics Data System (ADS)

    Wu, Yuefeng; Li, Fang; Zhang, Wentao; Xiao, Hao; Liu, Yuliang

    2008-11-01

    Polarization-induced phase noise in Michelson interferometer with imperfect Faraday rotator mirrors was investigated. This kind of noise generates from the rotation angle errors of Faraday rotator mirrors and external polarization perturbation. The conversion factor κ, representing the magnitude conversion ability from polarization-noise to polarization induced phase-noise, have been theoretically evaluated and experimentally investigated.

  15. Infra-red spectroscopic characteristics of naphthalocyanine in bis(naphthalocyaninato) rare earth complexes peripherally substituted with thiophenyl derivatives.

    PubMed

    Li, Xiaobo; Mao, Yajun; Xiao, Chi; Lu, Fanli

    2015-04-05

    The infra-red (IR) spectroscopic data for a series of eleven rare earth double-deckers MIII[Nc(SPh)8]2 (M=Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er) have been collected and systematically investigated. For MIII[Nc(SPh)8]2, typical IR marker bands for the naphthalocyanine anion radical [Nc(SPh)8].- were observed at 1317-1325 cm(-1) as the most intense absorption bands, which can be attributed to the pyrrole stretching. As for Ce[Nc(SPh)8]2, the typical IR marker band was also observed at 1317 cm(-1), which shows that the cerium complex exists as the form of CeIII[Nc(SPh)8]2-[Nc(SPh)8].-. In addition, both the Q-bands of electronic absorption spectra and the typical IR absorption bands of naphthalocyanine radical anion [Nc(SPh)8].- move to the high energy as the decrease of rare earth metal ionic radius. These facts suggest that the π-π electron interaction in these double-deckers becomes stronger along with the lanthanide contraction.

  16. HIGH-ALBEDO C-COMPLEX ASTEROIDS IN THE OUTER MAIN BELT: THE NEAR-INFRARED SPECTRA

    SciTech Connect

    Kasuga, Toshihiro; Usui, Fumihiko; Hasegawa, Sunao; Ootsubo, Takafumi; Kuroda, Daisuke

    2013-07-01

    Primitive, outer-belt asteroids are generally of low albedo, reflecting carbonaceous compositions like those of CI and CM meteorites. However, a few outer-belt asteroids having high albedos are known, suggesting the presence of unusually reflective surface minerals or, conceivably, even exposed water ice. Here, we present near-infrared (1.1-2.5 {mu}m) spectra of four outer-belt C-complex asteroids with albedos {>=}0.1. We find no absorption features characteristic of water ice (near 1.5 and 2.0 {mu}m) in the objects. Intimate mixture models set limits to the water ice by weight {<=}2%. Asteroids (723) Hammonia and (936) Kunigunde are featureless and have (60%-95%) amorphous Mg pyroxenes that might explain the high albedos. Asteroid (1276) Ucclia also shows a featureless reflection spectrum with (50%-60%) amorphous Mg pyroxenes. Asteroid (1576) Fabiola shows a possible weak, broad absorption band (1.5-2.1 {mu}m). The feature can be reproduced by (80%) amorphous Mg pyroxenes or orthopyroxene (crystalline silicate), either of which is likely to cause its high albedo. We discuss the origin of high-albedo components in primitive asteroids.

  17. High-albedo C-complex Asteroids in the Outer Main Belt: The Near-infrared Spectra

    NASA Astrophysics Data System (ADS)

    Kasuga, Toshihiro; Usui, Fumihiko; Ootsubo, Takafumi; Hasegawa, Sunao; Kuroda, Daisuke

    2013-07-01

    Primitive, outer-belt asteroids are generally of low albedo, reflecting carbonaceous compositions like those of CI and CM meteorites. However, a few outer-belt asteroids having high albedos are known, suggesting the presence of unusually reflective surface minerals or, conceivably, even exposed water ice. Here, we present near-infrared (1.1-2.5 μm) spectra of four outer-belt C-complex asteroids with albedos >=0.1. We find no absorption features characteristic of water ice (near 1.5 and 2.0 μm) in the objects. Intimate mixture models set limits to the water ice by weight <=2%. Asteroids (723) Hammonia and (936) Kunigunde are featureless and have (60%-95%) amorphous Mg pyroxenes that might explain the high albedos. Asteroid (1276) Ucclia also shows a featureless reflection spectrum with (50%-60%) amorphous Mg pyroxenes. Asteroid (1576) Fabiola shows a possible weak, broad absorption band (1.5-2.1 μm). The feature can be reproduced by (80%) amorphous Mg pyroxenes or orthopyroxene (crystalline silicate), either of which is likely to cause its high albedo. We discuss the origin of high-albedo components in primitive asteroids.

  18. Observation of near infrared and enhanced visible emissions from electroluminescent devices with organo samarium(III) complex

    NASA Astrophysics Data System (ADS)

    Chu, B.; Li, W. L.; Hong, Z. R.; Zang, F. X.; Wei, H. Z.; Wang, D. Y.; Li, M. T.; Lee, C. S.; Lee, S. T.

    2006-11-01

    Samarium (dibenzoylmethanato)3 bathophenanthroline (Sm(DBM)3 bath) was employed as an emitting and electron transport layer in organic light emitting diodes (OLEDs), and narrow electroluminescent (EL) emissions of a Sm3+ ion were observed in the visible and near infrared (NIR) region, differing from those of the same devices with Eu3+- or Tb3+-complex EL devices with the same structure. The EL emissions of the Sm3+-devices originate from transitions from 4G5/2 to the lower respective levels of Sm3+ ions. A maximum luminance of 490 cd m-2 at 15 V and an EL efficiency of 0.6% at 0.17 mA cm-2 were obtained in the visible region, and the improved efficiency should be attributed to introducing a transitional layer between the N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) film and the Sm(DBM)3 bath film and the avoidance of interfacial exciplex emission in devices. Sharp emissions of Sm3+ ions in the NIR region were also observed under a lower threshold value less than 4.5 V.

  19. Herschel far-infrared observations of the Carina Nebula complex - The embedded young stellar and protostellar population

    NASA Astrophysics Data System (ADS)

    Gaczkowski, Benjamin; Preibisch, Thomas; Ratzka, Thorsten; Roccatagliata, Veronica; Ohlendorf, Henrike; Pekruhl, Stephanie

    2013-07-01

    At a distance of 2.3 kpc, the Carina Nebula is the nearest southern region with a large enough massive stellar population to sample the top of the IMF and displays all phenomena of massive star formation. We have performed a 9 square-degree Herschel far-infrared survey of the Carina Nebula complex (CNC) which revealed, for the first time, the very complex and filamentary small-scale structure of the dense clouds. We discovered 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands. About 75% of these are Class 0 protostars with masses between about one and ten solar masses estimated from radiative transfer modeling. Taking the observational limits into account and extrapolating the observed number of Herschel-detected protostars over the stellar initial mass function suggests that the star formation rate of the CNC is about 0.017 solar masses per year. The spatial distribution of the Herschel young stellar objects (YSO) candidates is highly inhomogeneous and does not follow the distribution of cloud mass. Rather, most Herschel YSO candidates are found at the irradiated edges of clouds and pillars. The currently ongoing star formation process forms only low-mass and intermediate-mass stars, but no massive stars. The characteristic spatial configuration of the YSOs provides support to the picture that the formation of this latest stellar generation is triggered by the advancing ionization fronts. Around the bubble-shaped HII region Gum 31 (containing the young stellar cluster NGC 3324) in the north-western part of the CNC we identified 752 candidate YSOs from Spitzer, WISE, and Herschel data and analyzed their spectral energy distributions. Their location in the rim of the bubble is suggestive of their being triggered by a 'collect and collapse' scenario, which agrees well with the observed parameters of the region which we obtained from density and temperature maps from our Herschel data.

  20. The continuity of scientific discovery and its communication: the example of Michael Faraday.

    PubMed

    Gross, Alan G

    2009-02-25

    This paper documents the cognitive strategies that led to Faraday's first significant scientific discovery. For Faraday, discovery is essentially a matter seeing as, of substituting for the eye all possess the eye of analysis all scientists must develop. In the process of making his first significant discovery, Faraday learns to dismiss the magnetic attractions and repulsions he and others had observed; by means of systematic variations in his experimental set-up, he learns to see these motions as circular: it is the first indication that an electro-magnetic field exists. In communicating his discoveries, Faraday, of course, takes into consideration his various audiences' varying needs and their differences in scientific competence; but whatever his audience, Faraday learns to convey what it feels like to do science, to shift from seeing to seeing as, from sight to insight.

  1. Hydrogen-bonding effects on infrared spectra from anharmonic computations: uracil-water complexes and uracil dimers.

    PubMed

    Fornaro, Teresa; Burini, Diletta; Biczysko, Malgorzata; Barone, Vincenzo

    2015-05-07

    Hydrogen-bonding interactions lead to significant changes in the infrared (IR) spectrum, like frequency shifts of the order of magnitude of hundreds of cm(-1) and increases of IR intensity for bands related to vibrational modes of functional groups directly involved in the hydrogen-bonded bridges. We are actively developing a comprehensive and robust computational protocol aimed at the quantitative reproduction of the spectra of bio-organic and hybrid organic/inorganic molecular systems with a proper account of the variety of intra- and intermolecular interactions. We have resorted to fully anharmonic quantum mechanical computations within the generalized second-order vibrational perturbation theory (GVPT2) approach, combined with the B3LYP-D3 method, in conjunction with basis sets of double-ζ plus polarization quality. Such an approach has been validated in a previous work ( Phys. Chem. Chem. Phys. 2014 , 16 , 10112 - 10128 ) for simulating the IR spectra of the monomers of nucleobases and some of their dimers. In the present contribution we have extended our computational protocol toward hybrid models, with the harmonic part computed at the B2PLYP level, in conjunction with the maug-cc-pVTZ basis set, or by a cost-effective ONIOM B2PLYP:B3LYP focused model, where only part of the molecular system forming the hydrogen bonds is treated at the B2PLYP level of theory. In this work experimental frequencies available for a set of four uracil-water complexes have been considered as references for the computational methodologies applied to the simulation of hydrogen-bonding effects on the infrared spectrum, obtaining average uncertainties of about 22 cm(-1) for B3LYP-D3/N07D and improved description within 10 cm(-1) by hybrid B2PLYP/B3LYP-D3 approaches. The same computational schemes have been next applied to simulate fully anharmonic IR spectra of six different hydrogen-bonded uracil dimers, providing reliable support for future experimental investigations on hydrogen

  2. Faraday rotation enhancement of gold coated Fe2O3 nanoparticles: comparison of experiment and theory.

    PubMed

    Dani, Raj Kumar; Wang, Hongwang; Bossmann, Stefan H; Wysin, Gary; Chikan, Viktor

    2011-12-14

    Understanding plasmonic enhancement of nanoscale magnetic materials is important to evaluate their potential for application. In this study, the Faraday rotation (FR) enhancement of gold coated Fe(2)O(3) nanoparticles (NP) is investigated experimentally and theoretically. The experiment shows that the Faraday rotation of a Fe(2)O(3) NP solution changes from approximately 3 rad/Tm to 10 rad/Tm as 5 nm gold shell is coated on a 9.7 nm Fe(2)O(3) core at 632 nm. The results also show how the volume fraction normalized Faraday rotation varies with the gold shell thickness. From the comparison of experiment and calculated Faraday rotation based on the Maxwell-Garnett theory, it is concluded that the enhancement and shell dependence of Faraday rotation of Fe(2)O(3) NPs is a result of the shifting plasmon resonance of the composite NP. In addition, the clustering of the NPs induces a different phase lag on the Faraday signal, which suggests that the collective response of the magnetic NP aggregates needs to be considered even in solution. From the Faraday phase lag, the estimated time of the full alignment of the magnetic spins of bare (cluster size 160 nm) and gold coated NPs (cluster size 90 nm) are found to be 0.65 and 0.17 μs. The calculation includes a simple theoretical approach based on the Bruggeman theory to account for the aggregation and its effect on the Faraday rotation. The Bruggeman model provides a qualitatively better agreement with the experimentally observed Faraday rotation and points out the importance of making a connection between component properties and the average "effective" optical behavior of the Faraday medium containing magnetic nanoparticles.

  3. Faraday Rotation Due to Surface States in the Topological Insulator (Bi1–xSbx)2Te3

    DOE PAGES

    Shao, Yinming; Post, Kirk W.; Wu, Jhih-Sheng; ...

    2016-12-29

    For this research, using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. Finally, the FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing manymore » exotic quantum phenomena in topological insulators.« less

  4. Faraday Rotation Due to Surface States in the Topological Insulator (Bi1-xSbx)2Te3.

    PubMed

    Shao, Yinming; Post, Kirk W; Wu, Jhih-Sheng; Dai, Siyuan; Frenzel, Alex J; Richardella, Anthony R; Lee, Joon Sue; Samarth, Nitin; Fogler, Michael M; Balatsky, Alexander V; Kharzeev, Dmitri E; Basov, D N

    2017-02-08

    Using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. The FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing many exotic quantum phenomena in topological insulators.

  5. Probing the Faraday Effect of Polarized ^3He

    NASA Astrophysics Data System (ADS)

    Phelps, Gretchen; Abney, Josh; Korsch, Wolfgang

    2013-04-01

    The Faraday Effect refers to the phenomenon in which the polarization of light transmitted through a magnetized medium is rotated. The relation φ=VlB describes the magnitude of the rotation, where V is the material dependent Verdet constant and l is the length of the medium in an applied magnetic field B. Polarized ^3He, generated in a glass cell constructed of GE-180, gives rise to a Faraday rotation via nuclear spin optical rotation (NSOR), a measure of which establishes a new technique in ^3He polarization monitoring. Our set-up incorporates a triple-modulation technique with present sensitivities at the μrad level. This is accomplished through the combination of a photo-elastic modulator, an optical chopper, and a sinusoidally driven magnetic field. Several calibration samples were used to test the triple-modulation method. Good agreement between our results and the commonly accepted values for the Verdet constant was achieved. Technical challenges and progress towards the determination of V^3He will be presented.

  6. Comparison of Faraday rotation observations at Delhi with IRI model

    NASA Astrophysics Data System (ADS)

    Singh, L.; Gupta, J. K.; Tyagi, T. R.

    1996-01-01

    Comparison of Faraday rotation (FR) observations made at Delhi with FR computed from option II of the International Reference Ionosphere (IRI) shows that during low solar activity (1975-76) the IRI model grossly overestimates daytime Faraday rotation in all seasons by 185 to 320%. The premidnight and postmidnight values are also overestimated by 130 to 205% and 95 to 200% respectively. During high solar activity (1980), the daytime FR values predicted by the IRI are overestimated by 70 to 110%. The premidnight and postmidnight values are also overestimated by 55 to 115% and 100 to 280% respectively. However, it may be noted that in the 05 to 06 hour time slot, the estimates are within 20% in all seasons during low solar activity and in winter and autumnal equinox of high solar activity. It is suggested that instead of the CCIR set, a different set of co-efficients as applied in option I and II be derived based on the observed data obtained in the low latitude region.

  7. Elliptical polarization effects in a chromatically addressed Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Li, G. D.; Aspey, R. A.; Kong, M. G.; Gibson, J. R.; Jones, G. R.

    1999-01-01

    Optical polarization processes in a parallel-sided glass element used in a Faraday rotation current sensor have been considered. In such sensors the path length necessary to produce sufficient rotation of the plane of polarization is produced by a multiplicity of reflections within the glass element. It is shown that such reflections induce ellipticity of polarization and that this affects the current-sensing performance of the sensor. Two reflection cases, corresponding to total internal reflections at a glass-air interface and reflections by aluminium-coated surfaces, are considered. The latter are shown to produce higher optical attenuation but a lower degree of elliptical polarization. The implications of the induced elliptical polarization in relation to chromatically modulated polychromatic light are considered. It is shown that the resolution of the Faraday sensing is improved by minimizing the ellipticity of the polarization with the aluminium-coated reflections. However a greater dynamic range and signal strength may be achievable with the total internal reflection element.

  8. Resonant microsphere gyroscope based on a double Faraday rotator system.

    PubMed

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  9. Protection characteristics of a Faraday cage compromised by lightning burnthrough.

    SciTech Connect

    Warne, Larry Kevin; Bystrom, Edward; Jorgenson, Roy Eberhardt; Montoya, Sandra L.; Merewether, Kimball O.; Coats, Rebecca Sue; Martinez, Leonard E.; Jojola, John M.

    2012-01-01

    A lightning flash consists of multiple, high-amplitude but short duration return strokes. Between the return strokes is a lower amplitude, continuing current which flows for longer duration. If the walls of a Faraday cage are made of thin enough metal, the continuing current can melt a hole through the metal in a process called burnthrough. A subsequent return stroke can couple energy through this newly-formed hole. This LDRD is a study of the protection provided by a Faraday cage when it has been compromised by burnthrough. We initially repeated some previous experiments and expanded on them in terms of scope and diagnostics to form a knowledge baseline of the coupling phenomena. We then used a combination of experiment, analysis and numerical modeling to study four coupling mechanisms: indirect electric field coupling, indirect magnetic field coupling, conduction through plasma and breakdown through the hole. We discovered voltages higher than those encountered in the previous set of experiments (on the order of several hundreds of volts).

  10. Cs 728 nm Laser Spectroscopy and Faraday Atomic Filter

    NASA Astrophysics Data System (ADS)

    Liu, Zhong-Zheng; Tao, Zhi-Ming; Jiang, Zhao-Jie; Chen, Jing-Biao

    2014-12-01

    We mainly present the 728 nm laser spectroscopy and Faraday atomic filter of Cs atoms with 650 MHz linewidth and 2.6% transmission based on an electrodeless discharge vapor lamp, compared with Rb 728 nm laser spectroscopy. Accidentally, this remarkably strong Cs 728 nm transition from the 6F7/2 state to the 5D5/2 state is only about 2.5 GHz away from the Rb 728 nm transition of the future potential four-level active optical clock, once laser cooled and trapped from the 7S1/2 state to the 5P1/2 state, as we proposed previously. A Faraday atomic filter stabilized 728 nm laser using a Cs electrodeless discharge vapor lamp with a power of 10mW will provide a frequency reference to evaluate the performance of the potential Rb four-level active optical clock at 728 nm with power less than 1 nW by 2.5 GHz heterodyne measurements.

  11. Herschel far-infrared observations of the Carina Nebula complex. III. Detailed cloud structure and feedback effects

    NASA Astrophysics Data System (ADS)

    Roccatagliata, V.; Preibisch, T.; Ratzka, T.; Gaczkowski, B.

    2013-06-01

    Context. The star formation process in large clusters/associations can be strongly influenced by the feedback from high-mass stars. Whether the resulting net effect of the feedback is predominantly negative (cloud dispersal) or positive (triggering of star formation due to cloud compression) is still an open question. Aims: The Carina Nebula complex (CNC) represents one of the most massive star-forming regions in our Galaxy. We use our Herschel far-infrared observations to study the properties of the clouds over the entire area of the CNC (with a diameter of ≈3.2°, which corresponds to ≈125 pc at a distance of 2.3 kpc). The good angular resolution (10''-36'') of the Herschel maps corresponds to physical scales of 0.1-0.4 pc, and allows us to analyze the small-scale (i.e., clump-size) structures of the clouds. Methods: The full extent of the CNC was mapped with PACS and SPIRE in the 70, 160, 250, 350, and 500 μm bands. We determined temperatures and column densities at each point in these maps by modeling the observed far-infrared spectral energy distributions. We also derived a map showing the strength of the UV radiation field. We investigated the relation between the cloud properties and the spatial distribution of the high-mass stars and computed total cloud masses for different density thresholds. Results: Our Herschel maps resolve for the first time the small-scale structure of the dense clouds over the entire spatial extent of the CNC. Several particularly interesting regions, including the prominent pillars south of η Car, are analyzed in detail. We compare the cloud masses derived from the Herschel data with previous mass estimates based on sub-mm and molecular line data. Our maps also reveal a peculiar wave-like pattern in the northern part of the Carina Nebula. Finally, we characterize two prominent cloud complexes at the periphery of our Herschel maps, which are probably molecular clouds in the Galactic background. Conclusions: We find that the

  12. Novel Implementations of Faraday Rotation Spectroscopy - from In-Situ Radical Detection to Studies of Environmental Nitrogen Cycling

    NASA Astrophysics Data System (ADS)

    Zhang, Eric; Westberg, Jonas; Wysocki, Gerard

    2016-06-01

    Radical species play an important role in various chemical processes spanning atmospheric chemistry (e.g. ozone formation), bio-medical science, and combustion. These highly reactive chemicals usually occur at very low concentration levels, and are difficult to quantify in experiments1. Generally, laser-based techniques rely on careful selection of the target transition to minimize spectral interference and achieve high selectivity. In case of complex gas mixtures (such as air) a possibility of spectral interference always exists. Since Faraday rotation spectroscopy (FRS) is sensitive only to paramagnetic species (radicals), it can simultaneously provide ultra-high sensitivity and selectivity. In this talk an overview of novel designs of FRS instrumentation as well as applications of FRS sensing will be provided. Examples will be given for FRS systems that routinely operate at the fundamental limits of optical detection, cavity-enhanced FRS detection schemes for sensitivity enhancement towards sub-pptv detection limits2, and high-accuracy FRS spectrometers designed specifically for ratiometry of nitrogen isotopes (14N, 15N)3. Prospects for the FRS technology to monitor important atmospheric molecules such as HOx radicals (atmospheric "cleansing" agents) will be discussed. References: 1. Wennberg et al., "Aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals," Rev. Sci. Instrum. 65, 1858-1876 (1994). 2. Westberg et al., "Optical feedback cavity-enhanced Faraday rotation spectroscopy for oxygen detection," in CES2015(Boulder, CO, 2015). 3. Zhang, "Nitric Oxide Isotopic Analyzer Based on a Compact Dual-Modulation Faraday Rotation Spectrometer," Sensors 15, 25992 (2015).

  13. Investigating vibrational anharmonic couplings in cyanide-bridged transition metal mixed valence complexes using two-dimensional infrared spectroscopy

    SciTech Connect

    Slenkamp, Karla M.; Lynch, Michael S.; Van Kuiken, Benjamin E.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira

    2014-02-28

    Using polarization-selective two-dimensional infrared (2D IR) spectroscopy, we measure anharmonic couplings and angles between the transition dipole moments of the four cyanide stretching (ν{sub CN}) vibrations found in [(NH{sub 3}){sub 5}Ru{sup III}NCFe{sup II}(CN){sub 5}]{sup −} (FeRu) dissolved in D{sub 2}O and formamide and [(NC){sub 5}Fe{sup II}CNPt{sup IV}(NH{sub 3}){sub 4}NCFe{sup II}(CN){sub 5}]{sup 4−} (FePtFe) dissolved in D{sub 2}O. These cyanide-bridged transition metal complexes serve as model systems for studying the role of high frequency vibrational modes in ultrafast photoinduced charge transfer reactions. Here, we focus on the spectroscopy of the ν{sub CN} modes in the electronic ground state. The FTIR spectra of the ν{sub CN} modes of the bimetallic and trimetallic systems are strikingly different in terms of frequencies, amplitudes, and lineshapes. The experimental 2D IR spectra of FeRu and FePtFe and their fits reveal a set of weakly coupled anharmonic ν{sub CN} modes. The vibrational mode anharmonicities of the individual ν{sub CN} modes range from 14 to 28 cm{sup −1}. The mixed-mode anharmonicities range from 2 to 14 cm{sup −1}. In general, the bridging ν{sub CN} mode is most weakly coupled to the radial ν{sub CN} mode, which involves the terminal CN ligands. Measurement of the relative transition dipole moments of the four ν{sub CN} modes reveal that the FeRu molecule is almost linear in solution when dissolved in formamide, but it assumes a bent geometry when dissolved in D{sub 2}O. The ν{sub CN} modes are modelled as bilinearly coupled anharmonic oscillators with an average coupling constant of 6 cm{sup −1}. This study elucidates the role of the solvent in modulating the molecular geometry and the anharmonic vibrational couplings between the ν{sub CN} modes in cyanide-bridged transition metal mixed valence complexes.

  14. Very large array faraday rotation studies of the coronal plasma

    NASA Astrophysics Data System (ADS)

    Kooi, Jason Earl

    Knowledge of the coronal magnetic field is crucial for understanding (1) the heating mechanism(s) of the solar corona, (2) the acceleration of the fast solar wind, and (3) the structure and dynamics of coronal mass ejections (CMEs). Observation of Faraday rotation (FR) is one of the best remote-sensing techniques for determining plasma properties in the corona and can provide information on the plasma structure of a CME shortly after launch, shedding light on the initiation process. I used the Karl G. Jansky Very Large Array (VLA) to make sensitive Faraday rotation measurements to investigate the general plasma structure of the corona, properties of coronal plasma inhomogeneities and waves, and transients associated with coronal mass ejections. To enhance my measurements of FR transients, I also developed an algorithm in the Common Astronomy Software Applications (CASA) package to mitigate ionospheric Faraday rotation. In August, 2011, I made FR observations at 5.0 and 6.1 GHz of the radio galaxy 3C 228 through the solar corona at heliocentric distances of 4.6-5.0 solar radii using the VLA. Observations at 5.0 GHz permit measurements deeper in the corona than previous VLA observations at 1.4 and 1.7 GHz. These FR observations provided unique information on the magnetic field in this region of the corona. My data on 3C 228 provide two lines of sight (separated by 46 arcseconds, 33,000 km in the corona). I detected three periods during which there appeared to be a difference in the Faraday rotation measure between these two closely spaced lines of sight, which I used to estimate coronal currents; these values (ranging from 2.6 to 4.1 GA) are several orders of magnitude below that which is necessary for significant coronal heating (assuming the Spitzer resistivity). I also used the data to determine upper limits (3.3 and 6.4 rad/m2 along the two lines of sight) on FR fluctuations caused by coronal waves. These upper limits are comparable to and, thus, not inconsistent

  15. Infrared chemiluminescence study of CO + O 2 reaction on Pd(1 1 0): Activated complex of CO 2 formation at high CO coverage

    NASA Astrophysics Data System (ADS)

    Nakao, Kenji; Ito, Shin-ichi; Tomishige, Keiichi; Kunimori, Kimio

    2005-07-01

    The infrared chemiluminescence study of CO 2 formed during steady-state CO + O 2 reaction over Pd(1 1 0) under various CO/O 2 pressure ratios was carried out. Highly excited antisymmetric vibrational mode compared to bending vibrational mode was observed under reaction conditions at high CO coverage. This can be related to the activated complex of CO 2 formation in more linear form.

  16. Faraday rotation as a probe of coronal and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Mancuso, Salvatore

    Faraday rotation observations of polarized radiation from natural radio sources yield a unique diagnostic of coronal and astrophysical plasmas. We made observations of the radiogalaxy 4C+03.01 seen through the solar corona when the source was at a distance of 8.6 solar radii from the Sun. Nearly continuous polarimetric observations were made on March 28, 1997 with the Very Large Array (VLA) at frequencies of 1465 and 1635 MHz. Dual frequency polarization measurements yield the rotation measure, a quantity that is proportional to the product along the line of sight of the electron density and the line-of-sight component of the magnetic field. We measure a rotation measure of +6.2 +/- 1.0 rad m-2 attributable to the corona. We obtain a weak detection of rotation measure fluctuations which may be due to coronal Alfvén waves and derive model-dependent upper limits to the Alfvén wave flux at the coronal base. We also report dual frequency linear polarization observations of thirteen polarized radio sources made on four days in May 1997 at elongations ranging from 5 to 14 solar radii. A tridimensional model of the solar minimum corona was found to be in excellent agreement with the observed rotation measures and deviations from the values predicted by the model were suggestive of long wavelength coronal Alfvén waves. These observations were also used for detection of high frequency magnetohydrodynamic waves. These waves can be detected through a Faraday screen depolarization mechanism, that is a reduction of the observed degree of linear polarization of an extended polarized source when viewed through a medium in which the Faraday rotation varies randomly. The observations show no detectable depolarization, and rule out some turbulence models. Finally we derive expressions for auto- and cross- correlation functions of the Stokes parameters Q and U of the galactic synchrotron radiation. Fluctuations in the polarization characteristics of the galactic synchrotron

  17. VLA Measurements of Faraday Rotation through a Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Fischer, Patrick D.; Buffo, Jacob J.; Spangler, Steven R.

    2015-04-01

    Coronal mass ejections (CMEs) are large scale eruptions of plasma from the Sun that play an important role in space weather. Although CMEs have been an active field of research since their discovery in the 1970s, there is still much to understand. While the plasma structure of a CME is typically modeled as a magnetic flux rope, there is no consensus on the effective trigger that initiates a CME. Other issues include identifying what causes the shift towards non-equilibrium and how CMEs are accelerated after initiation. Faraday rotation (FR) is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME. FR observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch and shed light on the initiation process. We made sensitive Very Large Array (VLA) full-polarization observations in August, 2012, using L band (1 - 2 GHz) frequencies of a “constellation” of radio sources through the solar corona at heliocentric distances that ranged from 6 - 15 solar radii. Because is it difficult to predict whether any given line of sight to a background source will be occulted by a CME, we were only successful in capturing a single CME occultation out of three sessions. In LASCO C3 coronagraph images, the CME clearly occults a few of our sources, the most promising being 0843+1547. The line of sight for this latter source is clearly occulted by the outer loop structure and may also be occulted by the inner cavity most closely associated with the flux rope structure. Preliminary data analysis shows a Faraday rotation transient for 0843+1547; the Faraday rotation measure changes from ~ 0 before CME occultation, to a value of about -12 rad/m^2 before declining after CME passage. In this paper, we discuss the results of these FR observations and their implications in terms of models for the plasma structure of CMEs. This work was supported at the

  18. Faraday Rotation as a Probe of Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Kooi, J. E.; Spangler, S. R.; Kassim, N. E.

    2016-12-01

    Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the Sun that play an important role in space weather. Although CMEs have been an active field of research since their discovery in the 1970s, there is still much to understand about the plasma structure of CMEs. Faraday rotation (FR) is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME. FR observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch. We made sensitive Very Large Array (VLA) full-polarization observations in August, 2012, using 1 — 2 GHz frequencies of a "constellation" of radio sources through the solar corona at heliocentric distances that ranged from 6 — 15 solar radii. Of the nine sources observed, three were occulted by CMEs. In addition to our radioastronomical observations, which represent one of the first active hunts for CME Faraday rotation since Bird et al. (1985) and the first active hunt using the VLA, we obtained white-light coronagraph images from the LASCO/C3 instrument to determine the Thomson scattering brightness, BT, providing a means to independently estimate the plasma density and determine its contribution to the observed Faraday rotation. A constant density force-free flux rope embedded in the background corona was used to model the effects of the CMEs on BT and FR. The single flux rope model successfully reproduces the observed BT and FR profiles for two sources. The third source (0843+1547) was occulted by two CMEs and, therefore, we modeled observations of this source using two flux ropes embedded in the background corona. The two flux rope model successfully reproduces both BT and FR profiles for 0843+1547 and, in particular, the two flux rope model successfully replicates the appropriate slope in FR before and after occultation by the second CME and predicts the observed change in sign to FR > 0 at the end

  19. The (CH2)2O-H2O hydrogen bonded complex. Ab Initio calculations and Fourier transform infrared spectroscopy from neon matrix and a new supersonic jet experiment coupled to the infrared AILES beamline of synchrotron SOLEIL.

    PubMed

    Cirtog, M; Asselin, P; Soulard, P; Tremblay, B; Madebène, B; Alikhani, M E; Georges, R; Moudens, A; Goubet, M; Huet, T R; Pirali, O; Roy, P

    2011-03-31

    A series of hydrogen bonded complexes involving oxirane and water molecules have been studied. In this paper we report on the vibrational study of the oxirane-water complex (CH(2))(2)O-H(2)O. Neon matrix experiments and ab initio anharmonic vibrational calculations have been performed, providing a consistent set of vibrational frequencies and anharmonic coupling constants. The implementation of a new large flow supersonic jet coupled to the Bruker IFS 125 HR spectrometer at the infrared AILES beamline of the French synchrotron SOLEIL (Jet-AILES) enabled us to record first jet-cooled Fourier transform infrared spectra of oxirane-water complexes at different resolutions down to 0.2 cm(-1). Rovibrational parameters and a lower bound of the predissociation lifetime of 25 ps for the v(OH)(b) = 1 state have been derived from the rovibrational analysis of the ν(OH)(b) band contour recorded at respective rotational temperatures of 12 K (Jet-AILES) and 35 K (LADIR jet).

  20. A two-in-one Faraday rotator mirror exempt of active optical alignment.

    PubMed

    Wan, Qiong; Wan, Zhujun; Liu, Hai; Liu, Deming

    2014-02-10

    A two-in-one Faraday rotator mirror was presented, which functions as two independent Faraday rotation mirrors with a single device. With the introduction of a reflection lens as substitution of the mirror in traditional structure, this device is characterized by exemption of active optical alignment for the designers and manufacturers of Faraday rotator mirrors. A sample was fabricated by passive mechanical assembly. The insertion loss was measured as 0.46 dB/0.50 dB for the two independent ports, respectively.

  1. Permanent magnets for Faraday rotators inspired by the design of the magic sphere.

    PubMed

    Trénec, Gérard; Volondat, William; Cugat, Orphée; Vigué, Jacques

    2011-08-20

    Faraday polarization rotators are commonly used in laser experiments. Most Faraday materials have a nonnegligible absorption, which is a limiting factor for high power laser optical isolators or for intracavity optical diodes. By using a stronger magnetic field and a shorter length of Faraday material, one can obtain the same polarization rotation and a reduced absorption. In this paper, we describe two permanent magnet arrangements that are easy to build and produce magnetic fields up to 1.7 T, substantially more than commonly used. The field homogeneity is largely sufficient for a 30 dB isolation ratio. We finally discuss the prospects for producing even larger fields with permanent magnets.

  2. Inverse energy cascade and emergence of large coherent vortices in turbulence driven by Faraday waves.

    PubMed

    Francois, N; Xia, H; Punzmann, H; Shats, M

    2013-05-10

    We report the generation of large coherent vortices via inverse energy cascade in Faraday wave driven turbulence. The motion of floaters in the Faraday waves is three dimensional, but its horizontal velocity fluctuations show unexpected similarity with two-dimensional turbulence. The inverse cascade is detected by measuring frequency spectra of the Lagrangian velocity, and it is confirmed by computing the third moment of the horizontal velocity fluctuations. This is observed in deep water in a broad range of wavelengths and vertical accelerations. The results broaden the scope of recent findings on Faraday waves in thin layers [A. von Kameke et al., Phys. Rev. Lett. 107, 074502 (2011)].

  3. Electrical control of Faraday rotation at a liquid-liquid interface.

    PubMed

    Marinescu, Monica; Kornyshev, Alexei A; Flatté, Michael E

    2015-01-01

    A theory is developed for the Faraday rotation of light from a monolayer of charged magnetic nanoparticles at an electrified liquid-liquid interface. The polarization fields of neighboring nanoparticles enhance the Faraday rotation. At such interfaces, and for realistic sizes and charges of nanoparticles, their adsorption-desorption can be controlled with a voltage variation<1 V, providing electrovariable Faraday rotation. A calculation based on the Maxwell-Garnett theory predicts that the corresponding redistribution of 40 nm nanoparticles of yttrium iron garnet can switch a cavity with a quality factor larger than 10(4) for light of wavelength 500 nm at normal incidence.

  4. White LED based Faraday current sensor using a quartz wavelength encoder

    NASA Astrophysics Data System (ADS)

    Li, G. D.; Aspey, R. A.; Jones, G. R.

    1999-04-01

    The use of polychromatic light with chromatic modulation has been shown to provide a different approach to Faraday current sensing. In this contribution the use of purely white LEDs along with a quartz rotary encoder and a multiple reflection Faraday sensing element is described for realizing a practical form of a chromatic modulation Faraday current sensor. It is shown that such a sensor embodiment leads to a system sensitivity, for a chromatic system, which is approximately a factor of three times higher than previously reported (0.65 nm A -1 compared with 0.19 nm A -1).

  5. Development of an optical current transducer with a bulk type Faraday sensor for metering

    SciTech Connect

    Katsukawa, H.; Ishikawa, H.; Okajima, H.; Cease, T.W.

    1996-04-01

    An optical current transducer (OCT) with a bulk type Faraday sensor demonstrated 0.3% class accuracy for metering. The Faraday sensor had Bi{sub 12}SiO{sub 20} (BSO) single crystals with right and left optical rotatory power to cancel out temperature dependency. A prototype 161 kV OCT installed in a TVA substation verified 0.3% class performance. The OCT had the Faraday sensor, a gapped magnetic iron core, a 1.6 m optical insulator, and an optical interface.

  6. Experimental study of the mutual influence of fibre Faraday elements in a spun-fibre interferometer

    SciTech Connect

    Gubin, V P; Morshnev, S K; Przhiyalkovsky, Ya V; Starostin, N I; Sazonov, A I

    2015-08-31

    An all-spun-fibre linear reflective interferometer with two linked Faraday fibre coils is studied. It is found experimentally that there is mutual influence of Faraday fibre coils in this interferometer. It manifests itself as an additional phase shift of the interferometer response, which depends on the circular birefringence induced by the Faraday effect in both coils. In addition, the interferometer contrast and magneto-optical sensitivity of one of the coils change. A probable physical mechanism of the discovered effect is the distributed coupling of orthogonal polarised waves in the fibre medium, which is caused by fibre bend in the coil. (interferometry)

  7. Ramsey-CPT spectrum with the Faraday effect and its application to atomic clocks

    NASA Astrophysics Data System (ADS)

    Tian, Yuan; Tan, Bo-Zhong; Yang, Jing; Zhang, Yi; Gu, Si-Hong

    2015-06-01

    A method that obtains the Ramsey-coherent population trapping (CPT) spectrum with the Faraday effect is investigated. An experiment is implemented to detect the light polarization components generated from the Faraday effect. The experimental results agree with the theoretical calculations based on the Liouville equation. By comparing with the method without using the Faraday effect, the potential of this method for a CPT-based atomic clock is assessed. The results indicate that this method should improve the short-term frequency stability by several times. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304362 and 11204351).

  8. Drift suppression in a dual-polarization fiber optic gyroscope caused by the Faraday effect

    NASA Astrophysics Data System (ADS)

    Liu, Pan; Li, Xuyou; Guang, Xingxing; Xu, Zhenlong; Ling, Weiwei; Yang, Hanrui

    2017-07-01

    An investigation of the drift caused by the Faraday effect in a dual-polarization interferometric fiber optic gyroscope (IFOG) is presented. Both theoretical analysis and experimental results indicate that the Faraday effect phase drifts in two orthogonal polarizations of polarization-maintaining fiber always have opposite polarities that can be compensated effectively. When the interference signals of the two orthogonal polarized light waves are added up, the bias stability of the IFOG is improved significantly. This study is promising for reducing the drift of IFOG caused by the Faraday effect.

  9. Interplay of air and sand: Faraday heaping unravelled.

    PubMed

    van Gerner, Henk Jan; van der Hoef, Martin A; van der Meer, Devaraj; van der Weele, Ko

    2007-11-01

    We report on numerical simulations of a vibrated granular bed including the effect of the ambient air, generating the famous Faraday heaps known from experiment. A detailed analysis of the forces shows that the heaps are formed and stabilized by the airflow through the bed while the gap between bed and vibrating bottom is growing, confirming the pressure gradient mechanism found experimentally by Thomas and Squires [Phys. Rev. Lett. 81, 574 (1998)], with the addition that the airflow is partly generated by isobars running parallel to the surface of the granular bed. Importantly, the simulations also explain the heaping instability of the initially flat surface and the experimentally observed coarsening of a number of small heaps into a larger one.

  10. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    SciTech Connect

    Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

    2015-02-02

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

  11. Thin foil Faraday collector under burning plasma reactor like conditions

    NASA Astrophysics Data System (ADS)

    Aakhus-Witt, Andy; Hawbaker, James; Sayers, Jack; Cecil, Ed; Debay, Tim

    2002-04-01

    We are investigating thin foil Faraday collectors as a diagnostic for lost alpha particles from high yield d-t tokamak fusion plasmas. One advantage of this concept is the predicted ability to operate under fairly high neutron/gamma radiation backgrounds. We have tested this prediction by measuring the current from a thin (2.5 n) Ni foil placed in the core of the TRIGA fission reactor at the Denver Federal Center. At a maximum steady state power of 950 kW (1E13 n/cm2/s) a current of 1.2 nA/cm2 was measured. This measured current at the maximum power is somewhat larger than the calculated current (0.5 nA/cm2). These results, future planned measurements, and the application of this diagnostic to proposed burning plasma (BPX) experiments will be discussed.

  12. Effects of irregularity anisotropy on Faraday polarization fluctuations

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Nghiem, S. V.; Yoo, C.

    1989-01-01

    The previous model (Lee et al., 1982) of the Faraday polarization fluctuations (FPF) is extended after taking into account the anisotropic nature of the commonly observed, rodlike and sheetlike ionospheric irregularities. Striking effects of irregularity anisotropy are found in the longitudinal radio propagation. However, if the wave propagation angle is not small (say, greater than 5 deg), the effects of irregularity anisotropy on FPF introduced by rodlike irregularities weaken significantly, while those caused by sheetlike irregularities remain prominent. Therefore, under the same ionospheric propagation conditions, sheetlike ionospheric irregularities are more effective than rodlike ionospheric irregularities in causing the FPF of radio waves. It is expected that intense FPF of VHF radio signals can be observed not only near the equatorial anomaly but also in the auroral region.

  13. Advances in Optical Fiber-Based Faraday Rotation Diagnostics

    SciTech Connect

    White, A D; McHale, G B; Goerz, D A

    2009-07-27

    In the past two years, we have used optical fiber-based Faraday Rotation Diagnostics (FRDs) to measure pulsed currents on several dozen capacitively driven and explosively driven pulsed power experiments. We have made simplifications to the necessary hardware for quadrature-encoded polarization analysis, including development of an all-fiber analysis scheme. We have developed a numerical model that is useful for predicting and quantifying deviations from the ideal diagnostic response. We have developed a method of analyzing quadrature-encoded FRD data that is simple to perform and offers numerous advantages over several existing methods. When comparison has been possible, we have seen good agreement with our FRDs and other current sensors.

  14. Faraday Rotation Optical Isolator for 10.6-microm Radiation.

    PubMed

    Jacobs, S D; Teegarden, K J; Ahrenkiel, R K

    1974-10-01

    Measurements that have been performed indicate that hot-pressed ferromagnetic CdCr(2)S(4) would be a useful Faraday optical isolator material for laser systems at 10.6 microm. A large-aperture, liquid-nitrogen-cooled isolator, requiring modest magnetic fields with material of optimum thickness, would provide isolation in excess of 30 dB with insertion loss due to optical absorption in the active element of less than 3 dB. Consideration of its figure of merit indicates that hot-pressed CdCr(2)S(4) could be used as an isolator at 1.06 microm, introducing less than 2 dB insertion loss due to optical absorption at that wavelength.

  15. The response function of modulated grid Faraday cup plasma instruments

    NASA Technical Reports Server (NTRS)

    Barnett, A.; Olbert, S.

    1986-01-01

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager Plasma Science (PLS) experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. The theoretical formulas were tested by multi-sensor analysis of solar wind data. The tests indicate that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  16. Compensating Faraday Depolarization by Magnetic Helicity in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Brandenburg, Axel; Ashurova, Mohira B.; Jabbari, Sarah

    2017-08-01

    A turbulent dynamo in spherical geometry with an outer corona is simulated to study the sign of magnetic helicity in the outer parts. In agreement with earlier studies, the sign in the outer corona is found to be opposite to that inside the dynamo. Line-of-sight observations of polarized emission are synthesized to explore the feasibility of using the local reduction of Faraday depolarization to infer the sign of helicity of magnetic fields in the solar corona. This approach was previously identified as an observational diagnostic in the context of galactic magnetic fields. Based on our simulations, we show that this method can be successful in the solar context if sufficient statistics are gathered by using averages over ring segments in the corona separately for the regions north and south of the solar equator.

  17. Pseudo Magnetic Faraday and Quantum Hall Effect In Oscillating Graphene

    NASA Astrophysics Data System (ADS)

    Bhagat, Anita; Mullen, Kieran

    When a graphene layer is stressed, the strain changes the phase between sites in a tight binding model of the system. This phase can be viewed as a pseudo-magnetic vector potential. The corresponding pseudo-magnetic field has been experimentally verified in static cases. We examine the case of oscillating graphene ribbons and explore two new effects. The first is to investigate an oscillating pseudo-magnetic field that produces a quantum Hall effect: we calculate the I-V characteristic of an oscillating graphene nanoribbon as a function of frequency, and amplitude in both the oscillations and the applied driving voltage. Second, the time dependent pseudo-magnetic field should produce a pseudo-Faraday effect driving electrons in different valleys in opposite directions. In both cases, we make explicit calculations for experiment. This project was supported in part by the US National Science Foundation under Grant DMR-1310407.

  18. Macroscopic drift current in the inverse Faraday effect

    NASA Astrophysics Data System (ADS)

    Hertel, Riccardo; Fähnle, Manfred

    2015-01-01

    The inverse Faraday effect (IFE) describes the spontaneous magnetization of a conducting or dielectric medium due to irradiation with a circularly polarized electromagnetic wave. The effect has recently been discussed in the context of laser-induced magnetic switching of solids. We analyze analytically the electron dynamics induced by a circularly polarized laser beam within the framework of plasma theory. A macroscopic drift current is obtained, which circulates around the perimeter of the laser beam. The magnetic moment due to this macroscopic current has an opposite sign and half of the magnitude of the magnetic moment that is generated directly by the IFE. This constitutes an important contribution of angular momentum transferred from the wave to the medium and a classical mechanism for the light-induced generation of magnetic fields.

  19. The response function of modulated grid Faraday cup plasma instruments

    NASA Astrophysics Data System (ADS)

    Barnett, A.; Olbert, S.

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager Plasma Science (PLS) experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. The theoretical formulas were tested by multi-sensor analysis of solar wind data. The tests indicate that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  20. Faraday isolator stably operating in a wide temperature range

    NASA Astrophysics Data System (ADS)

    Mironov, E. A.; Voitovich, A. V.; Palashov, O. V.

    2016-03-01

    A method of stabilizing Faraday isolator characteristics at varying temperatures is proposed in this letter. The method is based on the use of a magnetic system with an inhomogeneous magnetic field and a magneto-optical element holder made of a material with a high value of thermal expansion coefficient. Changing the rotation angle of the polarization plane of radiation caused by the temperature variation of the magneto-optical element and the temperature dependence of its Verdet constant is compensated by its shifting in the magnetic field. The developed device demonstrates an isolation ratio of more than 40 dB at a temperature range of 25 °C. Estimates show the possibility of providing an isolation ratio of more than 45 dB in a temperature range of 60 °C.

  1. Non-destructive Faraday imaging of dynamically controlled ultracold atoms

    SciTech Connect

    Gajdacz, Miroslav; Pedersen, Poul L.; Mørch, Troels; Hilliard, Andrew J.; Arlt, Jan; Sherson, Jacob F.

    2013-08-15

    We describe an easily implementable method for non-destructive measurements of ultracold atomic clouds based on dark field imaging of spatially resolved Faraday rotation. The signal-to-noise ratio is analyzed theoretically and, in the absence of experimental imperfections, the sensitivity limit is found to be identical to other conventional dispersive imaging techniques. The dependence on laser detuning, atomic density, and temperature is characterized in a detailed comparison with theory. Due to low destructiveness, spatially resolved images of the same cloud can be acquired up to 2000 times. The technique is applied to avoid the effect of shot-to-shot fluctuations in atom number calibration, to demonstrate single-run vector magnetic field imaging and single-run spatial imaging of the system's dynamic behavior. This demonstrates that the method is a useful tool for the characterization of static and dynamically changing properties of ultracold atomic clouds.

  2. Aurora on Uranus - A Faraday disc dynamo mechanism

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Dessler, A. J.; Rassbach, M. E.

    1983-10-01

    A mechanism is proposed whereby the solar wind flowing past the magnetosphere of Uranus causes a Faraday disk dynamo topology to be established and power to be extracted from the kinetic energy of rotation of Uranus. An immediate consequence of this dynamo is the generation of Birkeland currents that flow in and out of the sunlit polar cap with the accompanying production of polar aurora. The power extracted from planetary rotation is calculated as a function of planetary dipole magnetic moment and the ionospheric conductivity of Uranus. For plausible values of ionospheric conductivity, the observed auroral power requires a magnetic moment corresponding to a surface equatorial field of the order of 4 Gauss, slightly larger than the value 1.8 Gauss given by the empirical 'magnetic Bodes law'.

  3. Sensitive Faraday rotation measurement with auto-balanced photodetection.

    PubMed

    Chang, Chia-Yu; Wang, Likarn; Shy, Jow-Tsong; Lin, Chu-En; Chou, Chien

    2011-06-01

    A magneto-optic polarimetry based on auto-balanced photodetection is investigated. In this experiment, a commercial auto-balanced photoreceiver is adopted to measure the Faraday rotation of air. With a proper setup to utilize its noise cancellation capability, the measurement can be flexible and sensitive. The angular sensitivity is 2.99×10(-8) rad Hz(-1/2), which is about 2.7 times the shot noise limit. The measured Verdet constant of air is +1.39×10(-9) rad G(-1) cm(-1) at 634.8 nm. Significantly we applied a small AC current to induce the magnetic field, so there was no heating in the coil. In addition, a double current modulation scheme was used to demonstrate that there was no zero drift and amplifier instability in the measurement. The possibility of improvement of the angular sensitivity and the potential applications are also discussed.

  4. Synthesis, thermogravimetric analysis, infrared, electronic and mass spectra of Mn(II), Co(II) and Fe(III) norfloxacin complexes

    NASA Astrophysics Data System (ADS)

    Sadeek, Sadeek A.

    2005-10-01

    The interactions of manganese acetate, ferric chloride and cobalt sulphate with norfloxacin (NOR) in acetone or methanol were studied. The isolated solid complexes were characterized by elemental analysis, infrared, electronic, mass spectra and thermal analysis. The results support the formation of complexes of the formula [Fe(NOR) 3]Cl 3·12H 2O and [M(NOR) 2]X 2·8H 2O (M=Mn(II) or Co(II) and X=(CH 3COO -) or SO4-2). The infrared spectra of the isolated solid complexes suggested, indicated that NOR act as bidentate ligands through one of the oxygen atoms of the carboxylic group and the ring carbonyl oxygen atom. The interpretation, mathematical analysis and evaluation of kinetic parameters of thermogravimetric (TGA) and its differential (DTG), such as entropy of activation, pre-exponential factors, activation energy evaluated by using Coats-Redfern and Horowitz-Metzger equations for two complexes are carried out. General mechanisms describing the decomposition of the solid complexes are suggested.

  5. Giant faraday rotation in conjugated, rod-like molecules

    NASA Astrophysics Data System (ADS)

    Vleugels, Rick; Brullot, Ward; Verbiest, Thierry

    2016-09-01

    Faraday rotation is a magneto-optic phenomenon in which the polarization plane of light is rotated due to magnetically induced circular birefringence. It can be used in a variety of applications such as optical isolators, magnetic field sensors and current sensors. So far, most of the applications use inorganic, paramagnetic materials, which have Verdet constants up to millions of degrees per tesla per meter in the visible spectrum range. They are performant at telecommunication wavelengths, though with smaller Verdet constants, so thicker materials are used. Disadvantages of these materials are their magnetic saturation at low magnetic fields and their strong temperature dependency. Organic, diamagnetic materials on the contrary, saturate at much larger magnetic fields and are less temperature dependent. Furthermore, they also have the advantage of their flexibility and processability. Up to now, magneto-optical research on organic materials has mostly characterized materials with low magneto-optical activity in regions without absorption, but there are some exceptions. Some pi-conjugated polymers have been shown to have very large magneto-optic responses. Furthermore, a mesogenic, organic molecule has been reported with a very high Verdet constant. Conclusive explanations for these large Verdet constants are still lacking, but different possible hypotheses were proposed. In our ongoing search for organic materials with exceptional magneto-optical properties, we examined conjugated, rod-like molecules. Structural, these molecules show close resemblances with the earlier reported mesogenic, organic molecule. We measured giant Verdet constants for thin films of these molecules, reaching values almost as giant as the previous reported mesogenic molecule. These findings shed first preliminary light on a structure-activity relationship for giant Faraday rotation in diamagnetic organic materials.

  6. Faraday wave patterns on a square cell network

    NASA Astrophysics Data System (ADS)

    Peña-Polo, Franklin; Vargas, Carlos A.; Vásquez-González, Benjamín; Medina, Abraham; Trujillo, Leonardo; Klapp, Jaime; Sigalotti, Leonardo Di G.

    2017-05-01

    We present the experimental observations of the Faraday instability when the vibrated liquid is contained in a network of small square cells for exciting frequencies in the range 10≤ F≤ 24 Hz. A sweep of the parameter space has been performed to investigate the amplitudes and frequencies of the driving force for which different patterns form over the network. Regular patterns in the form of square lattices are observed for driving frequencies in the range 10≤ F<14 Hz, while ordered matrices of oscillons are formed for 1423 Hz, disordered periodic patterns appear within individual cells for a small range of amplitudes. In this case, the wave field is dominated by oscillating blobs that interact on the capillary-gravity scale. A Pearson correlation analysis of the recorded videos shows that for all ordered patterns, the surface waves are periodic and correspond to Faraday waves of dominant frequency equal to half the excitation frequency (i.e., f=F/2). In contrast, the oscillons formed for 1423 Hz are not subharmonic and correspond to periodic harmonic waves with f=nF/2 (for n=2,4,\\ldots ). We find that the experimentally determined minimum forcing necessary to destabilize the rest state and generate surface waves is consistent with a recent stability analysis of stationary solutions as derived from a new dispersion relation for time-periodic waves with nonzero forcing and dissipation.

  7. Microscopic emission and reflectance thermal infrared spectroscopy: instrumentation for quantitative in situ mineralogy of complex planetary surfaces.

    PubMed

    Edwards, C S; Christensen, P R

    2013-04-10

    The diversity of investigations of planetary surfaces, especially Mars, using in situ instrumentation over the last decade is unprecedented in the exploration history of our solar system. The style of instrumentation that landed spacecraft can support is dependent on several parameters, including mass, power consumption, instrument complexity, cost, and desired measurement type (e.g., chemistry, mineralogy, petrology, morphology, etc.), all of which must be evaluated when deciding an appropriate spacecraft payload. We present a laboratory technique for a microscopic emission and reflectance spectrometer for the analysis of martian analog materials as a strong candidate for the next generation of in situ instruments designed to definitively assess sample mineralogy and petrology while preserving geologic context. We discuss the instrument capabilities, signal and noise, and overall system performance. We evaluate the ability of this instrument to quantitatively determine sample mineralogy, including bulk mineral abundances. This capability is greatly enhanced. Whereas the number of mineral components observed from existing emission spectrometers is high (often >5 to 10 depending on the number of accessory and alteration phases present), the number of mineral components at any microscopic measurement spot is low (typically <2 to 3). Since this style of instrument is based on a long heritage of thermal infrared emission spectrometers sent to orbit (the thermal emission spectrometer), sent to planetary surfaces [the mini-thermal emission spectrometers (mini-TES)], and evaluated in laboratory environments (e.g., the Arizona State University emission spectrometer laboratory), direct comparisons to existing data are uniquely possible with this style of instrument. The ability to obtain bulk mineralogy and atmospheric data, much in the same manner as the mini-TESs, is of significant additional value and maintains the long history of atmospheric monitoring for Mars

  8. A DFT study of infrared spectra and Monte Carlo predictions of the solvation shell of Praziquantel and β-cyclodextrin inclusion complex in liquid water.

    PubMed

    de Oliveira, C X; Ferreira, N S; Mota, G V S

    2016-01-15

    In this paper, we report a theoretical study of the inclusion complexes of Praziquantel (PZQ) and β-cyclodextrin (β-CD) in liquid water. The starting geometry has been carried out by molecular mechanics simulations, and afterwards optimized in B3LYP level with a 6-311G(d) basis set. Monte Carlo simulations have been used to calculate the solvation shell of the PZQ/β-CD inclusion complexes. Moreover, the vibrational frequencies and the infrared intensities for the PZQ/β-CD complex were computed using the B3LYP method. It is demonstrated that this combined model can yield well-converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly adequate for understanding the solute-solvent interaction used for generating the liquid structures of one solute surrounded by solvent molecules. The complex solvation shell showed an increase of the water molecule level in relation to the isolated PZQ molecule because of the hydrophilic effect of the CD molecule. The infrared spectra showed that the contribution that originated in the PZQ molecule was not predominant in the upper-wave number region in the drug/β-CD. The movement that purely originated in the PZQ molecule was localized in the absorption band, ranging from 1328 to 1688cm(-1).

  9. A DFT study of infrared spectra and Monte Carlo predictions of the solvation shell of Praziquantel and β-cyclodextrin inclusion complex in liquid water

    NASA Astrophysics Data System (ADS)

    de Oliveira, C. X.; Ferreira, N. S.; Mota, G. V. S.

    2016-01-01

    In this paper, we report a theoretical study of the inclusion complexes of Praziquantel (PZQ) and β-cyclodextrin (β-CD) in liquid water. The starting geometry has been carried out by molecular mechanics simulations, and afterwards optimized in B3LYP level with a 6-311G(d) basis set. Monte Carlo simulations have been used to calculate the solvation shell of the PZQ/β-CD inclusion complexes. Moreover, the vibrational frequencies and the infrared intensities for the PZQ/β-CD complex were computed using the B3LYP method. It is demonstrated that this combined model can yield well-converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly adequate for understanding the solute-solvent interaction used for generating the liquid structures of one solute surrounded by solvent molecules. The complex solvation shell showed an increase of the water molecule level in relation to the isolated PZQ molecule because of the hydrophilic effect of the CD molecule. The infrared spectra showed that the contribution that originated in the PZQ molecule was not predominant in the upper-wave number region in the drug/β-CD. The movement that purely originated in the PZQ molecule was localized in the absorption band, ranging from 1328 to 1688 cm- 1.

  10. Non-destructive testing of objects of complex shape using infrared thermography: rear surface reconstruction by temporal tracking of the thermal front

    NASA Astrophysics Data System (ADS)

    Djupkep Dizeu, F. B.; Laurendeau, Denis; Bendada, Abdelhakim

    2016-12-01

    Infrared thermography allows contactless non-destructive testing of objects based on their thermal behavior. Quantitative inspection of an object aims to characterize its internal defects by estimating their size and their depth. In the field, a one-dimensional thermal model has been used for depth estimation. Unfortunately, the methods based on this model become inaccurate when the inspected object has a high thermal diffusivity, a complex shape, or when the defects, like corrosion, have a complex geometry. For such cases, a 3D formulation of the problem is needed. In this paper, we consider the defect characterization as an inverse geometry problem and we propose a new method: the rear surface reconstruction by temporal tracking of the thermal front. The idea is to follow the thermal front while it propagates inside the object. Referring to the duality time-depth, at every moment, the penetration depth of the thermal front can be estimated. As soon as the thermal front reaches the rear surface, a temperature change will be noticeable on the frontal surface. It is then possible to update the internal geometry of the object at each time step in such a way that the difference between the theoretical temperature, obtained by a 3D solver, and the experimental temperature, recorded by an infrared camera, is minimized. The proposed method shows accurate results and can address situations involving rear surfaces with complex geometry and objects with high thermal diffusivity and a complex shape.

  11. Infrared spectra of CX2=CoX2 and CX3-CoX complexes from reactions of laser-ablated cobalt atoms with halomethanes.

    PubMed

    Cho, Han-Gook; Andrews, Lester

    2010-08-12

    Simple cobalt complexes with substantial carbon-cobalt double bond character are produced in Co atom reactions with tetra-, tri-, and dihalomethanes, whereas insertion complexes are identified only in the dihalomethane matrix infrared spectra. These complexes are identified from matrix infrared spectra and comparison with frequencies computed by density functional theory. Exclusive generation of carbenes in the tetrahalomethane systems is consistent with the computational results that the staggered allene-type conformer is the only meaningful energy minimum in the reaction path. Their short C-Co bondlengths of 1.732-1.764 A and CASSCF computed bond orders near 1.7 are also appropriate for carbon-cobalt double bonds. Hence, reactions of laser-ablated Co atoms are effective means to generate rarely reported high oxidation-state Co complexes with carbon-cobalt double bonds. Unlike the Rh and Ir cases, Co carbynes (with C-Co triple bonds) are not formed. The observation of CH(2)Cl-CoF with photoreversible intensity variation in the spectra provides unique insight on halogen migration from interconversion with CH(2)F-CoCl through the CH(2)=CoFCl carbene.

  12. Site-resolved imaging of single atoms with a Faraday quantum gas microscope

    NASA Astrophysics Data System (ADS)

    Yamamoto, Ryuta; Kobayashi, Jun; Kato, Kohei; Kuno, Takuma; Sakura, Yuto; Takahashi, Yoshiro

    2017-09-01

    We demonstrate a quantum gas microscope based on the Faraday effect that does not require a stochastic spontaneous emission process. We reveal the dispersive feature of this Faraday-imaging method by comparing the detuning dependence of the Faraday signal with that of the photon scattering rate. In addition, we determine the atom distribution through a deconvolution analysis, demonstrate absorption and dark-field Faraday imaging, and reveal the various shapes of the point spread functions for these methods, which are fully explained by a theoretical analysis. The results constitute an important first step toward ultimate quantum nondemolition site-resolved imaging and open the way to quantum feedback control of a quantum many-body system with single-site resolution.

  13. The effect of temperature characteristic of Faraday rotator to passively demodulated all optical fiber current transformers

    NASA Astrophysics Data System (ADS)

    Wang, Yuekun; Wang, Zhengping; Sun, Shuai

    2012-11-01

    In order to move signal detecting point to the most sensitive position and improve the immunity of the system at the same time, the scheme named passively demodulated all optical fiber current transformer (AOFCT) inserts a Faraday rotator of 22.5° rotation angle between fiber λ/4retarder and leading fiber. To improve the performance of this type of all fiber current transformer, after considering the temperature features of a large proportion of Faraday crystals, the effect of the Faraday rotator's temperature properties on temperature stability of the passively demodulated AOFCTs are theoretically analyzed and numerically calculated. The results show that the errors induced by the Faraday rotators are beyond the requested values in the International Standard IEC 60044-8:2002 of International Electrotechnical Commission (IEC) and the State Standard of P.R.China GB/T 20840.8-2007. Finally, to solve this problem, some possible solutions are suggested.

  14. Graphit-ceramic RF Faraday-thermal shield and plasma limiter

    DOEpatents

    Hwang, David L.; Hosea, Joel C.

    1989-01-01

    The present invention is directed to a process of brazing a ceramic mater to graphite. In particular, the brazing procedure is directed to the production of a novel brazed ceramic graphite product useful as a Faraday shield.

  15. RAPID COMMUNICATION: Vibration immunity and Ampere's circuital law for a near perfect triangular Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Fisher, N. E.; Jackson, D. A.

    1996-08-01

    We report a common-mode rejection scheme for a bulk-optic triangular Faraday current sensor that can eliminate optical noise induced by fibre-link vibration. The sensor's exploitation of Ampere's circuital law is also demonstrated.

  16. The Continuity of Scientific Discovery and Its Communication: The Example of Michael Faraday

    PubMed Central

    Gross, Alan G.

    2009-01-01

    This paper documents the cognitive strategies that led to Faraday’s first significant scientific discovery. For Faraday, discovery is essentially a matter seeing as, of substituting for the eye all possess the eye of analysis all scientists must develop. In the process of making his first significant discovery, Faraday learns to dismiss the magnetic attractions and repulsions he and others had observed; by means of systematic variations in his experimental set-up, he learns to see these motions as circular: it is the first indication that an electro-magnetic field exists. In communicating his discoveries, Faraday, of course, takes into consideration his various audiences’ varying needs and their differences in scientific competence; but whatever his audience, Faraday learns to convey what it feels like to do science, to shift from seeing to seeing as, from sight to insight. PMID:19350498

  17. Determination of the complex refractivity of Au, Cu and Al in terahertz and far-infrared regions from reflection spectra measurements

    NASA Astrophysics Data System (ADS)

    Mou, Yuan; Wu, Zhen-sen; Gao, Yan-qing; Yang, Zhi-qiang; Yang, Qiu-jie; Zhang, Geng

    2017-01-01

    A scheme to determine the complex refractivity of gold (Au), Copper (Cu) and Aluminum (Al) from measurements of ellipsometer and spectrometer are proposed in this paper. The reflection spectra of the metals from 4 THz to 40 THz are measured with spectrometer. The determined refractivity by Kramers-Kronig (KK) algorithm coincides with the measured results from ellipsometer in far infrared region. Drude model is invited to make the wing correction on the terahertz reflection spectra, which helps to eliminate the effects of the noises from spectrometer on KK algorithm. The calculated refractive indexes from measured spectra in terahertz region are in consistent with those from corrected reflection spectra. The advantage of the scheme is to obtain terahertz dispersion properties based on limited information in infrared region.

  18. Diode-laser frequency stabilization based on the resonant Faraday effect

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    The authors present the results of a method for frequency stabilizing laser diodes based on the resonant Faraday effects. A Faraday cell in conjunction with a polarizer crossed with respect to the polarization of the laser diode comprises the intracavity frequency selective element. In this arrangement, a laser pull-in range of 9 A was measured, and the laser operated at a single frequency with a linewidth less than 6 MHz.

  19. Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma

    SciTech Connect

    Jian Liu and Hong Qin

    2011-11-07

    The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.

  20. 45-dB Faraday isolator for 100 W average radiation power

    SciTech Connect

    Andreev, N F; Palashov, O V; Potemkin, A K; Sergeev, Aleksandr M; Khazanov, E A; Reitze, D H

    2000-12-31

    It is demonstrated experimentally that at high average radiation power, the optical isolation in the recently proposed design of a Faraday isolator is substantially higher than in the conventional scheme. The Faraday isolator with the isolation of 45 dB at the radiation power of 100 W is implemented. The data obtained show that a 30-dB isolator for the average laser radiation power of 1 kW can be realised. (laser applications and other topics in quantum electronics)

  1. Study of Charge Distribution in a Dust Beam using a Faraday Cup Assembly

    SciTech Connect

    Kausik, S.S.; Dutta, P.; Chakraborty, M.; Kakati, M.; Saikia, B.K.

    2005-10-31

    A Faraday cup assembly is employed to study the charge distribution in a dust beam. The Faraday Cup scans the dust beam across its diameter and the dust particle current is noted in an Electrometer. The variation of the pico ampere current, carried by the charged dust particles in the beam, is studied with change in the gas pressure. The observations provide an insight into the variation of the charge to mass ratio in a dust beam.

  2. Effects of Faraday Rotation on Microwave Remote Sensing From Space at L-Band

    NASA Technical Reports Server (NTRS)

    LeVine, D. M.; Kao, M.

    1997-01-01

    The effect of Faraday rotation on the remote sensing of soil moisture from space is investigated using the International Reference Ionosphere (IRI) to obtain electron density profiles and the International Geomagnetic Reference Field (IGRF) to model the magnetic field. With a judicious choice of satellite orbit (6 am, sunsynchronous) the errors caused by ignoring Faraday rotation are less than 1 K at incidence angles less than 40 degrees.

  3. Use of Near-Infrared Spectroscopy to Age-Grade and Identify Siblings of Anopheles Gambiae Complex

    USDA-ARS?s Scientific Manuscript database

    We used near-infrared spectroscopy (NIRS) to rapidly and non-destructively determine species and age of Anopheles gambiae ss (G3, Mali-NIH, Kisumu, ZANU, and Ifakara strains) and An. arabiensis (Dongola, KGB, and Ifakara strains). We developed NIR calibrations using mosquitoes reared and scanned at ...

  4. Enhanced modified faraday cup for determination of power density distribution of electron beams

    DOEpatents

    Elmer, John W.; Teruya, Alan T.

    2001-01-01

    An improved tomographic technique for determining the power distribution of an electron or ion beam using electron beam profile data acquired by an enhanced modified Faraday cup to create an image of the current density in high and low power ion or electron beams. A refractory metal disk with a number of radially extending slits, one slit being about twice the width of the other slits, is placed above a Faraday cup. The electron or ion beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. The enlarged slit enables orientation of the beam profile with respect to the coordinates of the welding chamber. A second disk having slits therein is positioned below the first slit disk and inside of the Faraday cup and provides a shield to eliminate the majority of secondary electrons and ions from leaving the Faraday cup. Also, a ring is located below the second slit disk to help minimize the amount of secondary electrons and ions from being produced. In addition, a beam trap is located in the Faraday cup to provide even more containment of the electron or ion beam when full beam current is being examined through the center hole of the modified Faraday cup.

  5. Linear theory on temporal instability of megahertz faraday waves for monodisperse microdroplet ejection.

    PubMed

    Tsai, Shirley C; Tsai, Chen S

    2013-08-01

    A linear theory on temporal instability of megahertz Faraday waves for monodisperse microdroplet ejection based on mass conservation and linearized Navier-Stokes equations is presented using the most recently observed micrometer- sized droplet ejection from a millimeter-sized spherical water ball as a specific example. The theory is verified in the experiments utilizing silicon-based multiple-Fourier horn ultrasonic nozzles at megahertz frequency to facilitate temporal instability of the Faraday waves. Specifically, the linear theory not only correctly predicted the Faraday wave frequency and onset threshold of Faraday instability, the effect of viscosity, the dynamics of droplet ejection, but also established the first theoretical formula for the size of the ejected droplets, namely, the droplet diameter equals four-tenths of the Faraday wavelength involved. The high rate of increase in Faraday wave amplitude at megahertz drive frequency subsequent to onset threshold, together with enhanced excitation displacement on the nozzle end face, facilitated by the megahertz multiple Fourier horns in resonance, led to high-rate ejection of micrometer- sized monodisperse droplets (>10(7) droplets/s) at low electrical drive power (<;1 W) with short initiation time (<;0.05 s). This is in stark contrast to the Rayleigh-Plateau instability of a liquid jet, which ejects one droplet at a time. The measured diameters of the droplets ranging from 2.2 to 4.6 μm at 2 to 1 MHz drive frequency fall within the optimum particle size range for pulmonary drug delivery.

  6. Experimental evidence for blue-shifted hydrogen bonding in the fluoroform-hydrogen chloride complex: a matrix-isolation infrared and ab initio study.

    PubMed

    Gopi, R; Ramanathan, N; Sundararajan, K

    2014-07-24

    The 1:1 hydrogen-bonded complex of fluoroform and hydrogen chloride was studied using matrix-isolation infrared spectroscopy and ab initio computations. Using B3LYP and MP2 levels of theory with 6-311++G(d,p) and aug-cc-pVDZ basis sets, the structures of the complexes and their energies were computed. For the 1:1 CHF3-HCl complexes, ab initio computations showed two minima, one cyclic and the other acyclic. The cyclic complex was found to have C-H · · · Cl and C-F · · · H interactions, where CHF3 and HCl sub-molecules act as proton donor and proton acceptor, respectively. The second minimum corresponded to an acyclic complex stabilized only by the C-F · · · H interaction, in which CHF3 is the proton acceptor. Experimentally, we could trap the 1:1 CHF3-HCl cyclic complex in an argon matrix, where a blue-shift in the C-H stretching mode of the CHF3 sub-molecule was observed. To understand the nature of the interactions, Atoms in Molecules and Natural Bond Orbital analyses were carried out to unravel the reasons for blue-shifting of the C-H stretching frequency in these complexes.

  7. Infrared absorption spectra of the CO(2)/H(2)O complex in a cryogenic nitrogen matrix--detection of a new bending frequency.

    PubMed

    Zhang, Xu; Sander, Stanley P

    2011-09-08

    Infrared absorption spectra have been measured for the mixture of CO(2) and H(2)O in a cryogenic nitrogen matrix. The 1:1 CO(2)/H(2)O complex has been observed. Each structure of this complex should have two bending frequencies corresponding to the CO(2) fundamental bending mode (ν(2)). In this work, three bending frequencies corresponding to the CO(2) fundamental bending mode (ν(2)) have been detected; one of them at 660.3 cm(-1) is reported here for the first time. This finding helps confirm the existence of two structures for this complex. A new feature attributed to a CO(2) and H(2)O complex is observed at 3604.4 cm(-1) and is tentatively assigned to the CO(2)/H(2)O complex band corresponding to the CO(2) combination mode (ν(3) + 2ν(2)). In addition, a band that belongs to a CO(2) and H(2)O complex is detected at 3623.8 cm(-1) for the first time and is tentatively assigned to the (CO(2))(2)/H(2)O complex band corresponding to the symmetric stretching mode (ν(1)) of H(2)O.

  8. Thermochemistry and infrared spectroscopy of neutral and cationic iron-polycyclic aromatic hydrocarbon complexes of astrophysical interest: fundamental density functional theory studies.

    PubMed

    Simon, Aude; Joblin, Christine

    2007-10-04

    This paper reports extensive calculations on the structural, thermodynamic, and mid-infrared spectroscopic properties of neutral and cationic model iron-polycyclic aromatic hydrocarbon (PAH) complexes of astrophysical interest for three PAHs of increasing size, namely, naphthalene (C10H8), pyrene (C16H10), and coronene (C24H12). Geometry optimizations and frequency calculations were performed using hybrid Hartree-Fock/density functional theory (DFT) methods. The use of DFT methods is mandatory in terms of computational cost and efficiency to describe the electronic and vibrational structures of such large organometallic unsaturated species that present several low-energy isomers of different structures and electronic and spin states. The calculated structures for the low-energy isomers of the model Fe-PAH and Fe-PAH+ complexes are presented and discussed. Iron-PAH binding energies are extracted, and the consequences of the coordination of iron on the infrared spectra of neutral and cationic PAHs are shown with systematic effects on band intensities and positions being demonstrated. The first results are discussed in terms of astrophysical implications. This work is the first step of an ongoing effort in our group to understand the photophysics and spectroscopy of iron-PAH complexes in the conditions of the interstellar medium using a synergy between observations, laboratory experiments, and theory.

  9. Near-Infrared Fluorescence Detection of Acetylcholine in Aqueous Solution Using a Complex of Rhodamine 800 and p-Sulfonato-calix[8]arene

    PubMed Central

    Jin, Takashi

    2010-01-01

    The complexing properties of p-sulfonatocalix[n]arenes (n = 4: S[4], n = 6: S[6], and n = 8: S[8]) for rhodamine 800 (Rh800) and indocyanine green (ICG) were examined to develop a near-infrared (NIR) fluorescence detection method for acetylcholine (ACh). We found that Rh800 (as a cation) forms an inclusion complex with S[n], while ICG (as a twitter ion) have no binding ability for S[n]. The binding ability of Rh800 to S[n] decreased in the order of S[8] > S[6] >> S[4]. By the formation of the complex between Rh800 and S[8], fluorescence intensity of the Rh800 was significantly decreased. From the fluorescence titration of Rh800 by S[8], stoichiometry of the Rh800-S[8] complex was determined to be 1:1 with a dissociation constant of 2.2 μM in PBS. The addition of ACh to the aqueous solution of the Rh800-S[8] complex caused a fluorescence increase of Rh800, resulting from a competitive replacement of Rh800 by ACh in the complex. From the fluorescence change by the competitive fluorophore replacement, stoichiometry of the Rh800-ACh complex was found to be 1:1 with a dissociation constant of 1.7 mM. The effects of other neurotransmitters on the fluorescence spectra of the Rh800-S[8] complex were examined for dopamine, GABA, glycine, and l-asparatic acid. Among the neurotransmitters examined, fluorescence response of the Rh800-S[8] complex was highly specific to ACh. Rh800-S[8] complexes can be used as a NIR fluorescent probe for the detection of ACh (5 × 10−4−10−3 M) in PBS buffer (pH = 7.2). PMID:22294934

  10. Metallopolymeric films based on a biscyclometalated ruthenium complex bridged by 1,3,6,8-tetra(2-pyridyl)pyrene: applications in near-infrared electrochromic windows.

    PubMed

    Yao, Chang-Jiang; Yao, Jiannian; Zhong, Yu-Wu

    2012-06-04

    A biscyclometalated ruthenium complex bridged by the 2,7-deprotonated form of 1,3,6,8-tetra(2-pyridyl)pyrene was deposited onto indium-tin oxide glass electrodes by reductive electropolymerization. The resulting metallopolymeric films exhibited tricolor electrochromic behavior in the near-infrared region upon switching of the two well-separated Ru(II/III) processes at low potentials. A good contrast ratio (35%) at 2050 nm and a long memory time up to 100 min were recorded for this electrochromic behavior. The response time is typically of a few seconds.

  11. The mean coronal magnetic field determined from Helios Faraday rotation measurements

    NASA Technical Reports Server (NTRS)

    Patzold, M.; Bird, M. K.; Volland, H.; Levy, G. S.; Seidel, B. L.; Stelzried, C. T.

    1987-01-01

    Coronal Faraday rotation of the linearly polarized carrier signals of the Helios spacecraft was recorded during the regularly occurring solar occultations over almost a complete solar cycle from 1975 to 1984. These measurements are used to determine the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3-10 solar radii, i.e., the range over which the complex fields at the coronal base are transformed into the interplanetary spiral. The mean coronal magnetic field in 1975-1976 was found to decrease with radial distance according to r exp-alpha, where alpha = 2.7 + or - 0.2. The mean field magnitude was 1.0 + or - 0.5 x 10 to the -5th tesla at a nominal solar distance of 5 solar radii. Possibly higher magnetic field strengths were indicated at solar maximum, but a lack of data prevented a statistical determination of the mean coronal field during this epoch.

  12. The mean coronal magnetic field determined from Helios Faraday rotation measurements

    NASA Technical Reports Server (NTRS)

    Patzold, M.; Bird, M. K.; Volland, H.; Levy, G. S.; Seidel, B. L.; Stelzried, C. T.

    1987-01-01

    Coronal Faraday rotation of the linearly polarized carrier signals of the Helios spacecraft was recorded during the regularly occurring solar occultations over almost a complete solar cycle from 1975 to 1984. These measurements are used to determine the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3-10 solar radii, i.e., the range over which the complex fields at the coronal base are transformed into the interplanetary spiral. The mean coronal magnetic field in 1975-1976 was found to decrease with radial distance according to r exp-alpha, where alpha = 2.7 + or - 0.2. The mean field magnitude was 1.0 + or - 0.5 x 10 to the -5th tesla at a nominal solar distance of 5 solar radii. Possibly higher magnetic field strengths were indicated at solar maximum, but a lack of data prevented a statistical determination of the mean coronal field during this epoch.

  13. Recognizing magnetic structures by present and future radio telescopes with Faraday rotation measure synthesis

    NASA Astrophysics Data System (ADS)

    Beck, R.; Frick, P.; Stepanov, R.; Sokoloff, D.

    2012-07-01

    Context. Modern radio telescopes allow us to record a large number of spectral channels. The application of a Fourier transform to spectropolarimetric data in radio continuum, Faraday rotation measure (RM) synthesis, yields the “Faraday spectrum”, which hosts valuable information about the magneto-ionic medium along the line of sight. Aims: We investigate whether the method of wavelet-based RM synthesis can help us to identify structures of regular and turbulent magnetic fields in extended magnetized objects, such as galaxies and galaxy clusters. Methods: The analysis of spectropolarimetric radio observations of multi-scale targets calls for a corresponding mathematical technique. Wavelets allow us to reformulate the RM synthesis method in a scale-dependent way and to visualize the data as a function of Faraday depth and scale. Results: We present observational tests to recognize magnetic field structures. A region with a regular magnetic field generates a broad “disk” in Faraday space, with two “horns” when the distribution of cosmic-ray electrons is broader than that of the thermal electrons. Each field reversal generates one asymmetric “horn” on top of the “disk”. A region with a turbulent field can be recognized as a “Faraday forest” of many components. These tests are applied to the spectral ranges of various synthesis radio telescopes. We argue that the ratio of maximum to minimum wavelengths determines the range of scales that can be identified in Faraday space. Conclusions: A reliable recognition of magnetic field structures in spiral galaxies or galaxy clusters requires the analysis of data cubes in position-position-Faraday depth space (“PPF cubes”), observed over a wide and continuous frequency range, allowing the recognition of a wide range of scales as well as high resolution in Faraday space. The planned Square Kilometre Array (SKA) will fulfill this condition and will be close to representing a perfect “Faraday

  14. Infrared spectra of the C2H2-(OCS)2 van der Waals complex: observation of a structure with C2 symmetry.

    PubMed

    Rezaei, Mojtaba; McKellar, A R W; Moazzen-Ahmadi, N

    2011-09-29

    Infrared spectra of the C(2)H(2)-(OCS)(2) trimer are studied by means of direct infrared absorption spectroscopy. The van der Waals complexes are generated in a supersonic slit-jet apparatus and probed using a rapid-scan tunable diode laser in the region of the ν(1) fundamental vibration of the OCS monomer. Two infrared bands are analyzed for the lowest energy isomer of the trimer, which has C(2) symmetry and is experimentally observed here for the first time. A relatively strong band centered at 2068.93 cm(-1) is assigned as the out-of-phase vibrations of the pair of equivalent OCS monomers. This band is blue-shifted relative to the free OCS monomer but with a reduced shift as compared with the analogous vibration of the nonpolar OCS dimer. A weaker red-shifted band observed at 2049.64 cm(-1) establishes the nonplanarity of the OCS dimer subunit within the trimer. Spectra for three isotopologues in addition to the normal form are used to help define an experimental structure, which agrees well with past and present semiempirical calculations.

  15. Blue-shift of the C-H stretching vibration in CHF3-H2O complex: Matrix isolation infrared spectroscopy and ab initio computations

    NASA Astrophysics Data System (ADS)

    Gopi, R.; Ramanathan, N.; Sundararajan, K.

    2016-09-01

    As a result of hydrogen bonding in CHF3-H2O complex, ab initio computations exhibited a blue shift in the C-H stretching region of CHF3 sub-molecule. In this work, we have investigated whether the blue-shifting in CHF3-H2O complex can be experimentally discerned using matrix isolation infrared spectroscopy. The 1:1 CHF3-H2O complex was therefore trapped and studied in argon and neon matrices. Experimentally a blue shift of 20.3 and 32.3 cm-1 in the C-H stretching region of CHF3 sub-molecule for the CHF3-H2O complex was observed in argon and neon matrices. The structure of the complex and the energies were computed at MP2 level of theory using a 6-311++G(d,p) and aug-cc-pVDZ basis sets. Computations indicated only one minimum corresponded to a C-H⋯O interaction between the hydrogen of fluoroform and oxygen of water. AIM and NBO analyses were performed to understand the reasons for blue-shifting of the C-H stretching wavenumber in the complex.

  16. Theory of Kerr and Faraday rotation in Topological Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Kargarian, Mehdi; Randeria, Mohit; Trivedi, Nandini

    2015-03-01

    Topological Weyl semimetals are characterized by bulk Dirac nodes separated in momentum space by a distance 2 b and lead to Fermi arcs in the surfaces electronic structure. We calculate the Faraday θF and Kerr θK angles for electromagnetic waves scattered from such a Weyl semimetal using the Kubo formalism. (1) For thin films with electromagnetic radiation incident on a surface without arcs, we show that θK = bd / απ and θF = απ / bd where α is the fine structure constant, and the film thickness d << λ , the wavelength. We further show multiple reflections give rise to giant Kerr rotation, under certain conditions, for a film on a substrate. (2) In the case when the electromagnetic radiation is incident on the surface with arcs, the wave propagating inside the material acquires a longitudinal component of the electric field proportional to b. We discuss the implications of our results for thin films of pyrochlore iridates, and also for the recently discovered Dirac semimetals in a magnetic field. We acknowledge the support of the CEM, an NSF MRSEC, under Grant DMR-1420451.

  17. Cavity ring-down Faraday rotation spectroscopy for oxygen detection

    NASA Astrophysics Data System (ADS)

    Westberg, Jonas; Wysocki, Gerard

    2017-05-01

    A combination of the path length enhancement provided by cavity ring-down spectroscopy together with the selectivity and noise suppression capabilities of Faraday rotation spectroscopy is utilized for highly sensitive detection of oxygen at 762.3 nm. The system achieves a noise-equivalent rotation angle of 1.3 × 10-9 rad/√Hz, and a trace O2 detection limit of 160 ppb for 100 s of averaging. The technique relies on measurements of the losses in two orthogonal polarization directions simultaneously, whereby an absolute assessment of the magnetically induced polarization rotation can be retrieved, analogous to the absolute absorption measurement provided by stand-alone cavity ring-down spectroscopy. The differential nature of the technique described here eliminates the need for off-resonance decay measurements and thereby allows for efficient shot-to-shot fluctuation suppression. This is especially advantageous when operating the system under measurement conditions that severely affect the non-absorber related losses, such as particulate matter contamination typically present in combustion or open-path applications.

  18. A sensitive Faraday rotation setup using triple modulation

    SciTech Connect

    Phelps, G.; Abney, J.; Broering, M.; Korsch, W.

    2015-07-15

    The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants of SF57 flint glass, pyrex glass, and air was tested. The sensitivity obtained shows that this technique may be implemented in future cell wall characterization and thickness measurements. We also discuss the first ever extraction of the Verdet constant of GE-180 glass for four wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the expected 1/λ{sup 2} dependence was observed.

  19. Probing the Rosette Nebula stellar bubble with Faraday rotation

    NASA Astrophysics Data System (ADS)

    Savage, Allison Hainline

    We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m-2. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m-2, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

  20. Homogenized boundary conditions and resonance effects in Faraday cages

    PubMed Central

    Hewitt, I. J.

    2016-01-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called ‘Faraday cage effect’). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells. PMID:27279775

  1. Two-dimensional Faraday instability with a spatially periodic bottom

    NASA Astrophysics Data System (ADS)

    Perinet, Nicolas; Falcon, Claudio; Shin, Seungwon; Chergui, Jalel; Juric, Damir

    2014-11-01

    We study two-dimensional Faraday waves in a channel with rectangular obstacles on the lower boundary, varying the height and the length of the obstacles as well as the distance separating them to understand their influence on the wave patterns. The analysis is mainly numerical and performed by means of BLUE, a code based on a hybrid Front-Tracking/Level-set algorithm for Lagrangian tracking of arbitrarily deformable phase interfaces. In the absence of obstacles, the bifurcation diagram shows three distinct instabilities: the classical instability that leads to the formation of patterns, the sudden onset of temporal chaos and finally a high jump in the amplitude of the waves, the latter bifurcation showing hysteresis. We show that the presence of obstacles delays the primary threshold, inhibits the secondary instabilities and enriches the dynamics of the interface. In particular, obstacles add a new spatial large-scale stationary mode and harmonics resulting from its interaction with the classical resonant modes. Powered@NLHPC: This research was partially supported by the supercomputing infrastructure of the NLHPC (ECM-02). Nicolas Perinet has received grant from CONICYT - FONDECYT/postdoctoral research Project 3140522.

  2. Scaling properties of weakly nonlinear coefficients in the Faraday problem.

    PubMed

    Skeldon, A C; Porter, J

    2011-07-01

    Interesting and exotic surface wave patterns have regularly been observed in the Faraday experiment. Although symmetry arguments provide a qualitative explanation for the selection of some of these patterns (e.g., superlattices), quantitative analysis is hindered by mathematical difficulties inherent in a time-dependent, free-boundary Navier-Stokes problem. More tractable low viscosity approximations are available, but these do not necessarily capture the moderate viscosity regime of the most interesting experiments. Here we focus on weakly nonlinear behavior and compare the scaling results derived from symmetry arguments in the low viscosity limit with the computed coefficients of appropriate amplitude equations using both the full Navier-Stokes equations and a reduced set of partial differential equations due to Zhang and Vinãls. We find the range of viscosities over which one can expect "low viscosity" theories to hold. We also find that there is an optimal viscosity range for locating superlattice patterns experimentally-large enough that the region of parameters giving stable patterns is not impracticably small, yet not so large that crucial resonance effects are washed out. These results help explain some of the discrepancies between theory and experiment.

  3. Homogenized boundary conditions and resonance effects in Faraday cages.

    PubMed

    Hewett, D P; Hewitt, I J

    2016-05-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called 'Faraday cage effect'). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

  4. Fabrication of a high power Faraday isolator by direct bonding

    NASA Astrophysics Data System (ADS)

    Rothhardt, Carolin; Rekas, Miroslaw; Kalkowski, Gerhard; Haarlammert, Nicoletta; Eberhardt, Ramona; Tünnermann, Andreas

    2013-03-01

    With increasing output power of lasers, absorption in optical components grows larger and demands on heat withdrawal become challenging. We report on the fabrication of a Faraday isolator for high power fiber laser applications (P = 1 kW) at a wavelength of 1080 nm and operation at ambient conditions. We investigate direct bonding of Terbium Gallium Garnet to sapphire disks, to benefit from the good heat spreading properties (having a 6-fold higher thermal conductivity than TGG) at high transparency of the latter. Successful bonding was achieved by extensive cleaning of the plane and smooth surfaces prior to low pressure plasma activation. The surfaces to be bonded were then contacted in a vacuum environment at elevated temperature under axial load. Our measurements show that the bonded interface has no measurable influence on transmission properties and bonded samples are stable for laser output powers of at least 260 W. As compared to a single Terbium Gallium Garnet substrate, wavefront aberrations were significantly decreased by bonding sapphire disks to Terbium Gallium Garnet.

  5. Na-Faraday rotation filtering: The optimal point

    PubMed Central

    Kiefer, Wilhelm; Löw, Robert; Wrachtrup, Jörg; Gerhardt, Ilja

    2014-01-01

    Narrow-band optical filtering is required in many spectroscopy applications to suppress unwanted background light. One example is quantum communication where the fidelity is often limited by the performance of the optical filters. This limitation can be circumvented by utilizing the GHz-wide features of a Doppler broadened atomic gas. The anomalous dispersion of atomic vapours enables spectral filtering. These, so-called, Faraday anomalous dispersion optical filters (FADOFs) can be by far better than any commercial filter in terms of bandwidth, transition edge and peak transmission. We present a theoretical and experimental study on the transmission properties of a sodium vapour based FADOF with the aim to find the best combination of optical rotation and intrinsic loss. The relevant parameters, such as magnetic field, temperature, the related optical depth, and polarization state are discussed. The non-trivial interplay of these quantities defines the net performance of the filter. We determine analytically the optimal working conditions, such as transmission and the signal to background ratio and validate the results experimentally. We find a single global optimum for one specific optical path length of the filter. This can now be applied to spectroscopy, guide star applications, or sensing. PMID:25298251

  6. PROBING THE ROSETTE NEBULA STELLAR BUBBLE WITH FARADAY ROTATION

    SciTech Connect

    Savage, Allison H.; Spangler, Steven R.; Fischer, Patrick D.

    2013-03-01

    We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m{sup -2}. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m{sup -2}, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

  7. Two-dimensional variational vibroequilibria and Faraday's drops

    NASA Astrophysics Data System (ADS)

    Gavrilyuk, Ivan; Lukovsky, Ivan; Timokha, Alexander

    2004-11-01

    When contacting with acoustically-vibrated structures a fluid volume can take a [time-averaged] geometric shape differing from capillary equilibrium. In accordance with theorems by Beyer et al. (2001) this shape (vibroequilibrium) furnishes a local minimum of a [quasi-potential energy] functional. The variational problem contains five dimensionless parameters evaluating the fluid volume, the wave number of acoustic field in the fluid domain, the contact angle and two newly-introduced numbers (η1, η2) giving relationships between (surface tension, gravitation) and Kapitsa’s vibrational forces/energy. The paper focuses on negligible small wave numbers (incompressible fluid) and two-dimensional flows. Although the variational problem may in some isolated cases have analytical solutions, it requires in general numerical approaches. Numerical examples simulate experiments by Wolf (1969) and Ganiyev et al. (1977) on vibroequilibria in horizontally vibrating tanks. These show that there appear at least two types of stable vibroequilibria associated with symmetric (possible non-connected) and asymmetric surface shapes. The paper represents also numerical results on flattening and vibrostabilisation of a drop hanging beneath a vibrating plate (experiments by Faraday (1831)).

  8. Hollow cathode lamp based Faraday anomalous dispersion optical filter.

    PubMed

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-07-15

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the (88)Sr (5s(2))(1)S0 - (5s5p)(1)P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization.

  9. Faraday Ripples, Parametric Resonance, and the Marangoni Effect.

    PubMed

    Birikh, Rudolf V.; Briskman, Vladimir A.; Cherepanov, Anatoly A.; Velarde, Manuel G.

    2001-06-01

    In general, the combined actions of two destabilizing mechanisms do not simply add to each other. Here we show that there is a subtle interplay between parametric excitation and thermal gradients leading to interfacial instability, overstability, and generation of surface waves. The case studied refers to the stability of a liquid layer with an open free surface subjected to a transverse temperature gradient (with the Marangoni effect) and also subjected to the simultaneous action of periodic vibrations normal to the layer. Stability is examined in the weak viscosity approximation by applying a multiscale method. To a first approximation, whatever the imposed thermal gradient, vibrations with fairly large amplitude are responsible for excitation of ripples with half the imposed vibration frequency, but their amplitude depends on the Marangoni number. However, as the Marangoni number increases, the critical amplitude decreases from the excitation threshold of Faraday ripples, and after passing through a minimum it monotonically increases with increasing thermal gradient. Another salient finding is that the threshold of the Marangoni overstability is found to be independent of the imposed vibration frequency and amplitude. Copyright 2001 Academic Press.

  10. A sensitive Faraday rotation setup using triple modulation

    NASA Astrophysics Data System (ADS)

    Phelps, G.; Abney, J.; Broering, M.; Korsch, W.

    2015-07-01

    The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants of SF57 flint glass, pyrex glass, and air was tested. The sensitivity obtained shows that this technique may be implemented in future cell wall characterization and thickness measurements. We also discuss the first ever extraction of the Verdet constant of GE-180 glass for four wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the expected 1/λ2 dependence was observed.

  11. Wave - fluid particle interaction in the Faraday waves

    NASA Astrophysics Data System (ADS)

    Francois, Nicolas; Xia, Hua; Punzmann, Horst; Shats, Michael

    2016-11-01

    Faraday waves are parametrically excited perturbations that appear on a liquid surface when the latter is vertically vibrated. Recently it has been discovered that: 1) such wave field can be described as a disordered lattice made of localised oscillating excitations, termed oscillons, 2) the horizontal motion of fluid particles on the water surface reproduces in detail the motion of fluid in two-dimensional turbulence. Here we report experimental measurements of the motion of both entities using Particle Image Velocimetry and Particle Tracking Velocimetry techniques. Those techniques allow to measure Lagrangian and Eulerian features of the oscillon motion and compare them with those of the fluid motion. A strong coupling is uncovered between the erratic motion of the waves and the turbulent agitation of the fluid particles. Both motions show Brownian-type dispersion and the r.m.s velocity of oscillons is directly related to the r.m.s. velocity of the fluid particles in a broad range of vertical accelerations. These results offer new perspectives for predicting surface fluid transport from the knowledge of the wave fields and vice versa. In particular, the broadening of the wave spectra at high wave amplitude can be predicted if the 2D turbulence energy is known. This work was supported by the Australian Research Council's Discovery Projects funding scheme (DP150103468 and DP160100863). NF acknowledges support by the Australian Research Council's DECRA Award (DE160100742).

  12. Faraday's Law, Lenz's Law, and Conservation of Energy

    NASA Astrophysics Data System (ADS)

    Wood, Lowell; Rottmann, Ray; Barrera, Regina

    2003-03-01

    A magnet accelerates upward through a coil and generates an emf that is recorded by a data acquisition system and a computer. Simultaneously, the position of the magnet as a function of time is recorded using a photogate/pulley system. When the circuit is completed by adding an appropriate load resistor, a current that opposes the flux change is generated in the coil. This current causes a magnetic field in the coil that decreases the acceleration of the rising magnet, a fact that is evident from the position versus time data. The energy dissipated by the resistance in the circuit is shown experimentally to equal the loss in mechanical energy of the system to within a few percent, thus demonstrating conservation of energy. The graphs of speed squared versus displacement show the changes in acceleration produced by the interaction of the induced current and the magnet. Students in introductory physics laboratories have successfully performed this experiment and are able to see many relevant features of Faraday's law.

  13. Hollow cathode lamp based Faraday anomalous dispersion optical filter

    PubMed Central

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-01-01

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the 88Sr (5s2)1S0 − (5s5p)1P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization. PMID:27418112

  14. SIMULATED FARADAY ROTATION MEASURES TOWARD HIGH GALACTIC LATITUDES

    SciTech Connect

    Akahori, Takuya; Kim, Jongsoo; Ryu, Dongsu; Gaensler, B. M. E-mail: akahori@physics.usyd.edu.au E-mail: ryu@canopus.cnu.ac.kr

    2013-04-20

    We study the Faraday rotation measure (RM) due to the Galactic magnetic field (GMF) toward high Galactic latitudes. The RM arises from the global, regular component as well as from the turbulent, random component of the GMF. We model the former based on observations and the latter using the data of magnetohydrodynamic turbulence simulations. For a large number of different GMF models, we produce mock RM maps around the Galactic poles and calculate various statistical quantities with the RM maps. We find that the observed medians of RMs toward the north and south Galactic poles, {approx}0.0 {+-} 0.5 rad m{sup -2} and {approx} + 6.3 {+-} 0.5 rad m{sup -2}, are difficult to explain with any of our many alternate GMF models. The standard deviation of observed RMs, {approx}9 rad m{sup -2}, is clearly larger than that of simulated RMs. The second-order structure function of observed RMs is substantially larger than that of simulated RMs, especially at small angular scales. We discuss other possible contributions to RM toward high Galactic latitudes. Besides observational errors and the intrinsic RM of background radio sources against which RM is observed, we suggest that the RM due to the intergalactic magnetic field may account for a substantial fraction of the observed RM. Finally, we note that reproducing the observed medians may require additional components or/and structures of the GMF that are not present in our models.

  15. Homogenized boundary conditions and resonance effects in Faraday cages

    NASA Astrophysics Data System (ADS)

    Hewett, D. P.; Hewitt, I. J.

    2016-05-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called `Faraday cage effect'). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

  16. Faraday rotation echo spectroscopy and detection of quantum fluctuations.

    PubMed

    Chen, Shao-Wen; Liu, Ren-Bao

    2014-04-15

    Central spin decoherence is useful for detecting many-body physics in environments and moreover, the spin echo control can remove the effects of static thermal fluctuations so that the quantum fluctuations are revealed. The central spin decoherence approach, however, is feasible only in some special configurations and often requires uniform coupling between the central spin and individual spins in the baths, which are very challenging in experiments. Here, by making analogue between central spin decoherence and depolarization of photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for studying quantum fluctuations in interacting spin systems. The echo control of the photon polarization is realized by flipping the polarization with a birefringence crystal. The FRES, similar to spin echo in magnetic resonance spectroscopy, can suppress the effects of the static magnetic fluctuations and therefore reveal dynamical magnetic fluctuations. We apply the scheme to a rare-earth compound LiHoF4 and calculate the echo signal, which is related to the quantum fluctuations of the system. We observe enhanced signals at the phase boundary. The FRES should be useful for studying quantum fluctuations in a broad range of spin systems, including cold atoms, quantum dots, solid-state impurities, and transparent magnetic materials.

  17. Infrared Stark and Zeeman spectroscopy of OH-CO: The entrance channel complex along the OH + CO → trans-HOCO reaction pathway

    NASA Astrophysics Data System (ADS)

    Brice, Joseph T.; Liang, Tao; Raston, Paul L.; McCoy, Anne B.; Douberly, Gary E.

    2016-09-01

    Sequential capture of OH and CO by superfluid helium droplets leads exclusively to the formation of the linear, entrance-channel complex, OH-CO. This species is characterized by infrared laser Stark and Zeeman spectroscopy via measurements of the fundamental OH stretching vibration. Experimental dipole moments are in disagreement with ab initio calculations at the equilibrium geometry, indicating large-amplitude motion on the ground state potential energy surface. Vibrational averaging along the hydroxyl bending coordinate recovers 80% of the observed deviation from the equilibrium dipole moment. Inhomogeneous line broadening in the zero-field spectrum is modeled with an effective Hamiltonian approach that aims to account for the anisotropic molecule-helium interaction potential that arises as the OH-CO complex is displaced from the center of the droplet.

  18. Solvation-induced σ-complex structure formation in the gas phase: a revisit to the infrared spectroscopy of [C6H6-(CH3OH)2]+.

    PubMed

    Mizuse, Kenta; Suzuki, Yuta; Mikami, Naohiko; Fujii, Asuka

    2011-10-20

    Structures of the [C(6)H(6)-(CH(3)OH)(2)](+) cluster cation are investigated with infrared (IR) spectroscopy. While the noncovalent type structure has been confirmed for the n = 1 cluster of [C(6)H(6)-(CH(3)OH)(n)](+), only contradictory interpretations have been given for the spectra of n = 2, in which significant changes have been observed with the Ar tagging. In the present study, we revisit IR spectroscopy of the n = 2 cluster from the viewpoint of the σ-complex structure, which includes a covalent bond formation between the benzene and methanol moieties. The observed spectral range is extended to the lower-frequency region, and the spectrum is measured with and without Ar and N(2) tagging. A strongly hydrogen-bonded OH stretch band, which is characteristic to the σ-complex structure, is newly found with the tagging. The remarkable spectral changes with the tagging are interpreted by the competition between the σ-complex and noncovalent complex structures in the [C(6)H(6)-(CH(3)OH)(2)](+) system. This result shows that the microsolvation only with one methanol molecule can induce the σ-complex structure formation.

  19. Me-3,2-HOPO Complexes of Near Infra-Red (NIR) Emitting Lanthanides: Efficient Sensitization of Yb(III) and Nd(III) in Aqueous Solution

    SciTech Connect

    Moore, Evan G.; Xu, Jide; Dodani, Sheel; Jocher, Christoph; D'Aleo, Anthony; Seitz, Michael; Raymond, Kenneth

    2009-11-10

    The synthesis, X-ray structure, solution stability, and photophysical properties of several trivalent lanthanide complexes of Yb(III) and Nd(III) using both tetradentate and octadentate ligand design strategies and incorporating the 1-methyl-3-hydroxy-pyridin-2-one (Me-3,2-HOPO) chelate group are reported. Both the Yb(III) and Nd(III) complexes have emission bands in the Near Infra-Red (NIR) region, and this luminescence is retained in aqueous solution ({Phi}{sub tot}{sup Yb} {approx} 0.09-0.22%). Furthermore, the complexes demonstrate very high stability (pYb {approx} 18.8-21.9) in aqueous solution, making them good candidates for further development as probes for NIR imaging. Analysis of the low temperature (77 K) photophysical measurements for a model Gd(III) complex were used to gain an insight into the electronic structure, and were found to agree well with corresponding TD-DFT calculations at the B3LYP/6-311G{sup ++}(d,p) level of theory for a simplified model monovalent sodium complex.

  20. Me-3,2-HOPO Complexes of Near Infra-Red (NIR) Emitting Lanthanides: Efficient Sensitization of Yb(III) and Nd(III) in Aqueous Solution

    PubMed Central

    Moore, Evan G.; Xu, Jide; Dodani, Sheel C.; Jocher, Christoph J.; D'Aléo, Anthony; Seitz, Michael; Raymond, Kenneth N.

    2011-01-01

    The synthesis, X-ray structure, solution stability, and photophysical properties of several trivalent lanthanide complexes of Yb(III) and Nd(III) using both tetradentate and octadentate ligand design strategies and incorporating the 1-methyl-3-hydroxy-pyridin-2-one (Me-3,2-HOPO) chelate group are reported. Both the Yb(III) and Nd(III) complexes have emission bands in the Near Infra-Red (NIR) region, and this luminescence is retained in aqueous solution (ΦtotYb~0.09−0.22%). Furthermore, the complexes demonstrate very high stability (pYb ~ 18.8 – 21.9) in aqueous solution, making them good candidates for further development as probes for NIR imaging. Analysis of the low temperature (77 K) photophysical measurements for a model Gd(III) complex were used to gain an insight into the electronic structure, and were found to agree well with corresponding TD-DFT calculations at the B3LYP/6-311G++(d,p) level of theory for a simplified model monovalent sodium complex. PMID:20364838

  1. CATION-π and CH-π Interactions in the Coordination and Solvation of Cu+ (ACETYLENE)n (n=1-6) Complexes Investigated via Infrared Photodissociation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Brathwaite, Antonio David; Walters, Richard S.; Ward, Timothy B.; Duncan, Michael A.

    2015-06-01

    Mass-selected copper-acetylene cation complexes of the form Cu(C2H2)n+ are produced by laser ablation and studied via infrared laser photodissociation spectroscopy in the C-H stretching region (3000-3500 wn). Spectra for larger species are measured via ligand elimination, whereas argon tagging is employed to enhance dissociation yields in smaller complexes. The number of infrared active bands, their frequency positions and their relative intensities provide insight into the structure and bonding of these ions. Density functional theory calculations are carried out in support of this work. The combined data show that cation-π bonds are formed for the n=1-3 species, resulting in red-shifted C-H stretches on the acetylene ligands. Three acetylene ligands complete the coordination of the copper cation. Additional ligands (n=4-6) solvate the n=3 core by forming CH-pi bonds. Distinctive vibrational patterns are exhibited for coordinated vs. solvent ligands. Theory reproduces these results.

  2. Complex organic matter in space: about the chemical composition of carriers of the Unidentified Infrared Bands (UIBs) and protoplanetary emission spectra recorded from certain astrophysical objects.

    PubMed

    Cataldo, Franco; Keheyan, Yeghis; Heymann, Dieter

    2004-02-01

    In this communication we present the basic concept that the pure PAHs (Polycyclic Aromatic Hydrocarbons) can be considered only the ideal carriers of the UIBs (Unidentified Infrared Bands), the emission spectra coming from a large variety of astronomical objects. Instead we have proposed that the carriers of UIBs and of protoplanetary nebulae (PPNe) emission spectra are much more complex molecular mixtures possessing also complex chemical structures comparable to certain petroleum fractions obtained from the petroleum refining processes. The demonstration of our proposal is based on the comparison between the emission spectra recorded from the protoplanetary nebulae (PPNe) IRAS 22272+ 5435 and the infrared absorption spectra of certain 'heavy' petroleum fractions. It is shown that the best match with the reference spectrum is achieved by highly aromatic petroleum fractions. It is shown that the selected petroleum fractions used in the present study are able to match the band pattern of anthracite coal. Coal has been proposed previously as a model for the PPNe and UIBs but presents some drawbacks which could be overcome by adopting the petroleum fractions as model for PPNe and UIBs in place of coal. A brief discussion on the formation of the petroleum-like fractions in PPNe objects is included.

  3. Modulating the near-infrared luminescence of neodymium and ytterbium complexes with tridentate ligands based on benzoxazole-substituted 8-hydroxyquinolines.

    PubMed

    Shavaleev, Nail M; Scopelliti, Rosario; Gumy, Frédéric; Bünzli, Jean-Claude G

    2009-04-06

    An improved synthesis of 2-(2'-benzothiazole)- and 2-(2'-benzoxazole)-8-hydroxyquinoline ligands that combine a tridentate N,N,O-chelating unit for metal binding and extended chromophore for light harvesting is developed. The 2-(2'-benzoxazole)-8-hydroxyquinoline ligands form mononuclear nine-coordinate complexes with neodymium, [Nd(kappa(3)-ligand)(3)], and an eight-coordinate complex with ytterbium, [Yb(kappa(3)-ligand)(2) x (kappa(1)-ligand) x H(2)O], as verified by crystallographic characterization of five complexes with four different ligands. The chemical stability of the complexes increases when the ligand contains 5,7-dihalo-8-hydroxyquinoline versus an 8-hydroxyquinoline group. The complexes feature a ligand-centered visible absorption band with a maximum at 508-527 nm and an intensity of (7.5-9.6) x 10(3) M(-1) x cm(-1). Upon excitation with UV and visible light within ligand absorption transitions, the complexes display characteristic lanthanide luminescence in the near-infrared at 850-1450 nm with quantum yields and lifetimes in the solid state at room temperature as high as 0.33% and 1.88 micros, respectively. The lanthanide luminescence in the complexes is enhanced upon halogenation of the 5,7-positions in the 8-hydroxyquinoline group and upon the addition of electron-donating substituents to the benzoxazole ring. Facile modification of chromophore units in 2-(2'-benzoxazole)-8-hydroxyquinoline ligands provides means for controlling the luminescence properties of their lanthanide complexes.

  4. The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure

    SciTech Connect

    Groenewold, G. S.; van Stipdonk, Michael J.; Oomens, Jos; De Jong, Wibe A.; McIIwain, Michael E.

    2011-12-01

    The infrared spectrum of the bis-uranyl nitrate complex [(UO2)2(NO3)5]- was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex [(UO2)2(NO3)5]- compared to the mono-complex [UO2(NO3)3]-, as indicated by a higher O-U-O asymmetric stretching (v3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

  5. Near-infrared absorbing and emitting Ru(II)-Pt(II) heterodimetallic complexes of dpdpz (dpdpz = 2,3-di(2-pyridyl)-5,6-diphenylpyrazine).

    PubMed

    Wu, Si-Hai; Burkhardt, Stephen E; Yao, Jiannian; Zhong, Yu-Wu; Abruña, Héctor D

    2011-05-02

    The reaction of 2,3-di(2-pyridyl)-5,6-diphenylpyrazine (dpdpz) with K(2)PtCl(4) in a mixture of acetonitrile and water afforded mono-Pt complex (dpdpz)PtCl(2)4 in good yield, with two lateral pyridine nitrogen atoms binding to the metal center. Two types of Ru(II)-Pt(II) heterodimetallic complexes bridged by dpdpz, namely, [(bpy)(2)Ru(dpdpz)Pt(C≡CC(6)H(4)R)](2+) (7-9, R = H, NMe(2), or Cl, respectively) and [(tpy)Ru(dpdpz)Pt(C≡CPh)] (+) (12), were then designed and prepared, where bpy = 2,2'-bipyridine and tpy = 2,2';6',2''-terpyridine. In both cases, the platinum atom binds to dpdpz with a C(∧)N(∧)N tridentate mode. However, the coordination of the ruthenium atom with dpdpz could either be noncyclometalated (N(∧)N bidentate) or cyclometalated (C(∧)N(∧)N tridentate). The electronic properties of these complexes were subsequently studied and compared by spectroscopic and electrochemical analyses and theoretical calculations. These complexes exhibit substantial absorption in the visible to NIR (near-infrared) region because of mixed MLCT (metal-to-ligand-charge-tranfer) transitions from both the ruthenium and the platinum centers. Complexes 7 and 9 were found to emit NIR light with higher quantum yields than those of the mono-Ru complex [(bpy)(2)Ru(dpdpz)](2+) (5) and bis-Ru complex [(bpy)(2)Ru(dpdpz)Ru(bpy)(2)](4+) (13). However, no emission was detected from complex 8 or 12 at room temperature in acetonitrile.

  6. The gas-phase bis-uranyl nitrate complex [(UO2)(2)(NO3)(5)](-): infrared spectrum and structure

    SciTech Connect

    Gary S. Groenewold; Michael J. van Stipdonk; Jos Oomens; Wibe de Jong; Michael E. McIlwain

    2011-12-01

    The infrared spectrum of the bis-uranyl nitrate complex [(UO{sub 2}){sub 2}(NO{sub 3}){sub 5}]{sup -} was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate nu3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex [(UO{sub 2}){sub 2}(NO{sub 3}){sub 5}]{sup -} compared to the mono-complex [UO{sub 2}(NO{sub 3}){sub 3}]{sup -}, as indicated by a higher O-U-O asymmetric stretching (nu3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the {nu}{sub 3} frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The structure was calculated using density functional theory (B3LYP functional), which produced a structure in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

  7. Faraday tomography of the local interstellar medium with LOFAR: Galactic foregrounds towards IC 342

    NASA Astrophysics Data System (ADS)

    Van Eck, C. L.; Haverkorn, M.; Alves, M. I. R.; Beck, R.; de Bruyn, A. G.; Enßlin, T.; Farnes, J. S.; Ferrière, K.; Heald, G.; Horellou, C.; Horneffer, A.; Iacobelli, M.; Jelić, V.; Martí-Vidal, I.; Mulcahy, D. D.; Reich, W.; Röttgering, H. J. A.; Scaife, A. M. M.; Schnitzeler, D. H. F. M.; Sobey, C.; Sridhar, S. S.

    2017-01-01

    Magnetic fields pervade the interstellar medium (ISM), but are difficult to detect and characterize. The new generation of low-frequency radio telescopes, such as the Low Frequency Array (LOFAR: a Square Kilometre Array-low pathfinder), provides advancements in our capability of probing Galactic magnetism through low-frequency polarimetry. Maps of diffuse polarized radio emission and the associated Faraday rotation can be used to infer properties of, and trace structure in, the magnetic fields in the ISM. However, to date very little of the sky has been probed at high angular and Faraday depth resolution. We observed a 5° by 5° region centred on the nearby galaxy IC 342 (ℓ = 138.2°,b = + 10.6°) using the LOFAR high-band antennae in the frequency range 115-178 MHz. We imaged this region at 4'.5x3'.8 resolution and performed Faraday tomography to detect foreground Galactic polarized synchrotron emission separated by Faraday depth (different amounts of Faraday rotation). Our Faraday depth cube shows a rich polarized structure, with up to 30 K of polarized emission at 150 MHz. We clearly detect two polarized features that extend over most of the field, but are clearly separated in Faraday depth. Simulations of the behaviour of the depolarization of Faraday-thick structures at such low frequencies show that such structures would be too strongly depolarized to explain the observations. These structures are therefore rejected as the source of the observed polarized features. Only Faraday thin structures will not be strongly depolarized at low frequencies; producing such structures requires localized variations in the ratio of synchrotron emissivity to Faraday depth per unit distance. Such variations can arise from several physical phenomena, such as a transition between regions of ionized and (mostly) neutral gas. We conclude that the observed polarized emission is Faraday thin, and propose that the emission originates from two mostly neutral clouds in the local ISM

  8. Faraday laser using 1.2 km fiber as an extended cavity

    NASA Astrophysics Data System (ADS)

    Tao, Zhiming; Zhang, Xiaogang; Pan, Duo; Chen, Mo; Zhu, Chuanwen; Chen, Jingbiao

    2016-07-01

    We demonstrate a Faraday laser using a 1.2 km fiber as an extended cavity, which provides optical feedback and obtains small free spectrum range (FSR) of 83 kHz, and have succeeded in limiting the laser frequency to a crossover transition {5}2{S}1/2,F=2\\to {5}2{P}3/2,F\\prime =1,3 of the natural 87Rb at 780 nm. The Faraday laser is based on a Faraday anomalous dispersion optical filter (FADOF) with an ultra-narrow bandwidth and the long fiber extended cavity of 1.2 km. The peak transmission assigned to the crossover transition F=2\\to F\\prime =1,3 in the FADOF is 20.5% with an ultra-narrow bandwidth of 29.1 MHz. The Allan deviation of the Faraday laser is around 6.0× {10}-11 in 0.06 to 1 s sampling time. Laser frequency is always kept in the center of the transmitted peak assigned to F=2\\to F\\prime =1,3. The Faraday laser realized here can provide light exactly resonant with an atomic transition used for atom-photon interaction experiments and is insensitive to diode temperature and injection current fluctuations.

  9. A Faraday laser lasing on Rb 1529 nm transition.

    PubMed

    Chang, Pengyuan; Peng, Huanfa; Zhang, Shengnan; Chen, Zhangyuan; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2017-08-21

    We present the design and performance characterization of a Faraday laser directly lasing on the Rb 1529 nm transition (Rb, 5P 3/2 - 4D 5/2) with high stability, narrow spectral linewidth and low cost. This system does not need an additional frequency-stabilized pump laser as a prerequisite to preparing Rb atom from 5S to 5P excited state. Just by using a performance-improved electrodeless discharge lamp-based excited-state Faraday anomalous dispersion optical filter (LESFADOF), we realized a heterogeneously Faraday laser with the frequency corresponding to atomic transition, working stably over a range of laser diode (LD) current from 85 mA to 171 mA and the LD temperature from 11 °C to 32 °C, as well as the 24-hour long-term frequency fluctuation range of no more than 600 MHz. Both the laser linewidth and relative intensity noisy (RIN) are measured. The Faraday laser lasing on Rb 1529 nm transition (telecom C-band) can be applied to further research on metrology, microwave photonics and optical communication systems. Besides, since the transitions correspongding to the populated excited-states of alkali atoms within lamp are extraordinarily rich, this scheme can increase the flexibility for choosing proper wavelengths for Faraday laser and greatly expand the coverage of wavelength corresponding to atomic transmission for laser frequency stabilization.

  10. 18-22 cm VLBA Faraday rotation studies of six AGN jets

    NASA Astrophysics Data System (ADS)

    Motter, J. C.; Gabuzda, D. C.

    2017-05-01

    The formation of relativistic jets in active galactic nuclei (AGN) is related to accretion on to their central supermassive black holes, and magnetic fields are believed to play a central role in launching, collimating and accelerating the jet streams from very compact regions out to kiloparsec or megaparsec scales. In the presence of helical or toroidal magnetic fields threading the AGN jets and their immediate vicinity, gradients in the observed Faraday rotation measures are expected due to the systematic change in the line-of-sight component of the magnetic field across the jet. We have analysed total intensity, linear polarization, fractional polarization and Faraday rotation maps based on very long baseline array data obtained at four wavelengths in the 18-22 cm range for six AGN (OJ 287, 3C 279, PKS 1510-089, 3C 345, BL Lac and 3C 454.3). These observations typically probe projected distances out to tens of parsecs from the observed core, and are well suited for Faraday rotation studies due to the relatively long wavelengths used and the similarity of the structures measured at the different wavelengths. We have identified statistically significant, monotonic, transverse Faraday rotation gradients across the jets of four of these six sources, as well as a tentative transverse Faraday rotation gradient across the jet of OJ 287, providing evidence for the presence of toroidal magnetic fields, which may be one component of helical magnetic fields associated with these AGN jets.

  11. Position control of desiccation cracks by memory effect and Faraday waves.

    PubMed

    Nakayama, Hiroshi; Matsuo, Yousuke; Takeshi, Ooshida; Nakahara, Akio

    2013-01-01

    Pattern formation of desiccation cracks on a layer of a calcium carbonate paste is studied experimentally. This paste is known to exhibit a memory effect, which means that a short-time application of horizontal vibration to the fresh paste predetermines the direction of the cracks that are formed after the paste is dried. While the position of the cracks (as opposed to their direction) is still stochastic in the case of horizontal vibration, the present work reports that their positioning is also controllable, at least to some extent, by applying vertical vibration to the paste and imprinting the pattern of Faraday waves, thus breaking the translational symmetry of the system. The experiments show that the cracks tend to appear in the node zones of the Faraday waves: in the case of stripe-patterned Faraday waves, the cracks are formed twice more frequently in the node zones than in the anti-node zones, presumably due to the localized horizontal motion. As a result of this preference of the cracks to the node zones, the memory of the square lattice pattern of Faraday waves makes the cracks run in the oblique direction differing by 45 degrees from the intuitive lattice direction of the Faraday waves.

  12. Diagnostics of the solar corona from comparison between Faraday rotation measurements and magnetohydrodynamic simulations

    SciTech Connect

    Le Chat, G.; Cohen, O.; Kasper, J. C.; Spangler, S. R.

    2014-07-10

    Polarized natural radio sources passing behind the Sun experience Faraday rotation as a consequence of the electron density and magnetic field strength in coronal plasma. Since Faraday rotation is proportional to the product of the density and the component of the magnetic field along the line of sight of the observer, a model is required to interpret the observations and infer coronal structures. Faraday rotation observations have been compared with relatively ad hoc models of the corona. Here for the first time we compare these observations with magnetohydrodynamic (MHD) models of the solar corona driven by measurements of the photospheric magnetic field. We use observations made with the NRAO Very Large Array of 34 polarized radio sources occulted by the solar corona between 5 and 14 solar radii. The measurements were made during 1997 May, and 2005 March and April. We compare the observed Faraday rotation values with values extracted from MHD steady-state simulations of the solar corona. We find that (1) using a synoptic map of the solar magnetic field just one Carrington rotation off produces poorer agreements, meaning that the outer corona changes in the course of one month, even in solar minimum; (2) global MHD models of the solar corona driven by photospheric magnetic field measurements are generally able to reproduce Faraday rotation observations; and (3) some sources show significant disagreement between the model and the observations, which appears to be a function of the proximity of the line of sight to the large-scale heliospheric current sheet.

  13. Time-resolved infrared (TRIR) study on the formation and reactivity of organometallic methane and ethane complexes in room temperature solution

    PubMed Central

    Cowan, Alexander J.; Portius, Peter; Kawanami, Hajime K.; Jina, Omar S.; Grills, David C.; Sun, Xue-Zhong; McMaster, Jonathan; George, Michael W.

    2007-01-01

    We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M(η5C5R5)(CO)2(L) [where M = Mn or Re, R = H or CH3 (Re only); and L = CH4 or C2H6]. In all cases, the methane complexes are found to be short-lived and significantly more reactive than the analogous n-heptane complexes. Re(Cp)(CO)2(CH4) and Re(Cp*)(CO)2(L) [Cp* = η5C5(CH3)5 and L = CH4, C2H6] were found to be in rapid equilibrium with the alkyl hydride complexes. In the presence of CO, both alkane and alkyl hydride complexes decay at the same rate. We have used picosecond time-resolved infrared spectroscopy to directly monitor the photolysis of Re(Cp*)(CO)3 in scCH4 and demonstrated that the initially generated Re(Cp*)(CO)2(CH4) forms an equilibrium mixture of Re(Cp*)(CO)2(CH4)/Re(Cp*)(CO)2(CH3)H within the first few nanoseconds (τ = 2 ns). The ratio of alkane to alkyl hydride complexes varies in the order Re(Cp)(CO)2(C2H6):Re(Cp)(CO)2(C2H5)H > Re(Cp*)(CO)2(C2H6):Re(Cp*)(CO)2(C2H5)H ≈ Re(Cp)(CO)2(CH4):Re(Cp)(CO)2(CH3)H > Re(Cp*)(CO)2(CH4):Re(Cp*)(CO)2(CH3)H. Activation parameters for the reactions of the organometallic methane and ethane complexes with CO have been measured, and the ΔH‡ values represent lower limits for the CH4 binding enthalpies to the metal center of WCH4 (30 kJ·mol−1), MnCH4 (39 kJ·mol−1), and ReCH4 (51 kJ·mol−1) bonds in W(CO)5(CH4), Mn(Cp)(CO)2(CH4), and Re(Cp)(CO)2(CH4), respectively. PMID:17409190

  14. Time-resolved infrared (TRIR) study on the formation and reactivity of organometallic methane and ethane complexes in room temperature solution.

    PubMed

    Cowan, Alexander J; Portius, Peter; Kawanami, Hajime K; Jina, Omar S; Grills, David C; Sun, Xue-Zhong; McMaster, Jonathan; George, Michael W

    2007-04-24

    We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M(eta5-C5R5)(CO)2(L) [where M = Mn or Re, R = H or CH3 (Re only); and L = CH4 or C2H6]. In all cases, the methane complexes are found to be short-lived and significantly more reactive than the analogous n-heptane complexes. Re(Cp)(CO)2(CH4) and Re(Cp*)(CO)2(L) [Cp* = eta5-C5(CH3)(5) and L = CH4, C2H6] were found to be in rapid equilibrium with the alkyl hydride complexes. In the presence of CO, both alkane and alkyl hydride complexes decay at the same rate. We have used picosecond time-resolved infrared spectroscopy to directly monitor the photolysis of Re(Cp*)(CO)3 in scCH4 and demonstrated that the initially generated Re(Cp*)(CO)2(CH4) forms an equilibrium mixture of Re(Cp*)(CO)2(CH4)/Re(Cp*)(CO)2(CH3)H within the first few nanoseconds (tau = 2 ns). The ratio of alkane to alkyl hydride complexes varies in the order Re(Cp)(CO)2(C2H6):Re(Cp)(CO)2(C2H5)H > Re(Cp*)(CO)2(C2H6):Re(Cp*)(CO)2(C2H5)H approximately equal to Re(Cp)(CO)2(CH4):Re(Cp)(CO)2(CH3)H > Re(Cp*)(CO)2(CH4):Re(Cp*)(CO)2(CH3)H. Activation parameters for the reactions of the organometallic methane and ethane complexes with CO have been measured, and the DeltaH++ values represent lower limits for the CH4 binding enthalpies to the metal center of W-CH4 (30 kJ.mol(-1)), Mn-CH4 (39 kJ.mol(-1)), and Re-CH4 (51 kJ.mol(-1)) bonds in W(CO)5(CH4), Mn(Cp)(CO)2(CH4), and Re(Cp)(CO)2(CH4), respectively.

  15. KENNEDY SPACE CENTER, FLA. - In Hangar A&E, Cape Canaveral Air Force Station, encapsulation of the Space Infrared Telescope Facility (SIRTF) is complete. The spacecraft will be transported to Launch Complex 17-B for mating with its launch vehicle, the Delta II rocket. SIRTF consists of three cryogenically cooled science instruments and an 0.85-meter telescope, and is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-08-07

    KENNEDY SPACE CENTER, FLA. - In Hangar A&E, Cape Canaveral Air Force Station, encapsulation of the Space Infrared Telescope Facility (SIRTF) is complete. The spacecraft will be transported to Launch Complex 17-B for mating with its launch vehicle, the Delta II rocket. SIRTF consists of three cryogenically cooled science instruments and an 0.85-meter telescope, and is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

  16. KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the Delta II Heavy rocket waits the arrival of the mobile service tower with three additional solid rocket boosters (SRBs). Nine 46-inch-diameter, stretched SRBs will help launch the Space Infrared Telescope Facility (SIRTF). Consisting of three cryogenically cooled science instruments and an 0.85-meter telescope, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-07-22

    KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the Delta II Heavy rocket waits the arrival of the mobile service tower with three additional solid rocket boosters (SRBs). Nine 46-inch-diameter, stretched SRBs will help launch the Space Infrared Telescope Facility (SIRTF). Consisting of three cryogenically cooled science instruments and an 0.85-meter telescope, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

  17. KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket waits to be lifted up and moved into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-07-18

    KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket waits to be lifted up and moved into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

  18. KENNEDY SPACE CENTER, FLA. - A worker at Hangar A&E, Cape Canaveral Air Force Station, tightens the canister around the Space Infrared Telescope Facility (SIRTF). The spacecraft will be transported to Launch Complex 17-B for mating with its launch vehicle, the Delta II rocket. SIRTF consists of three cryogenically cooled science instruments and an 0.85-meter telescope, and is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-08-07

    KENNEDY SPACE CENTER, FLA. - A worker at Hangar A&E, Cape Canaveral Air Force Station, tightens the canister around the Space Infrared Telescope Facility (SIRTF). The spacecraft will be transported to Launch Complex 17-B for mating with its launch vehicle, the Delta II rocket. SIRTF consists of three cryogenically cooled science instruments and an 0.85-meter telescope, and is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

  19. KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is nearly erect for its move into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-07-18

    KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is nearly erect for its move into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

  20. KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is moved into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.

    NASA Image and Video Library

    2003-07-18

    KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is moved into the mobile service tower. The rocket is being erected to launch the Space InfraRed Telescope Facility (SIRTF). Consisting of an 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF is one of NASA's largest infrared telescopes to be launched. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground.