Infrared emission spectra from operating elastohydrodynamic sliding contacts

NASA Technical Reports Server (NTRS)

Lauer, J. L.

1976-01-01

Infrared emission spectra from an operating EHD sliding contact were obtained through a diamond window for an aromatic polymer solute present in equal concentration in four different fluids. Three different temperature ranges, three different loads, and three different speeds for every load were examined. Very sensitive Fourier spectrophotometric (Interferometric) techniques were employed. Band Intensities and band intensity ratios found to depend both on the operating parameters and on the fluid. Fluid film and metal surface temperatures were calculated from the spectra and their dependence on the mechanical parameters plotted. The difference between these temperatures could be plotted against shear rate on one curve for all fluids. However, at the same shear rate the difference between bulk fluid temperature and diamond window temperature was much higher for one of the fluids, a traction fluid, than for the others.

Standardization of milk infrared spectra for the retroactive application of calibration models.

PubMed

Bonfatti, V; Fleming, A; Koeck, A; Miglior, F

2017-03-01

The objective of this study was to standardize the infrared spectra obtained over time and across 2 milk laboratories of Canada to create a uniform historical database and allow (1) the retroactive application of calibration models for prediction of fine milk composition; and (2) the direct use of spectral information for the development of indicators of animal health and efficiency. Spectral variation across laboratories and over time was inspected by principal components analysis (PCA). Shifts in the PCA scores were detected over time, leading to the definition of different subsets of spectra having homogeneous infrared signal. To evaluate the possibility of using common equations on spectra collected by the 2 instruments and over time, we developed a standardization (STD) method. For each subset of data having homogeneous infrared signal, a total of 99 spectra corresponding to the percentiles of the distribution of the absorbance at each wavenumber were created and used to build the STD matrices. Equations predicting contents of saturated fatty acids, short-chain fatty acids, and C18:0 were created and applied on different subsets of spectra, before and after STD. After STD, bias and root mean squared error of prediction decreased by 66% and 32%, respectively. When calibration equations were applied to the historical nonstandardized database of spectra, shifts in the predictions could be observed over time for all investigated traits. Shifts in the distribution of the predictions over time corresponded to the shifts identified by the inspection of the PCA scores. After STD, shifts in the predicted fatty acid contents were greatly reduced. Standardization reduced spectral variability between instruments and over time, allowing the merging of milk spectra data from different instruments into a common database, the retroactive use of calibrations equations, or the direct use of the spectral data without restrictions. Copyright © 2017 American Dairy Science

Connecting infrared spectra with plant traits to identify species

NASA Astrophysics Data System (ADS)

Buitrago, Maria F.; Skidmore, Andrew K.; Groen, Thomas A.; Hecker, Christoph A.

2018-05-01

Plant traits are used to define species, but also to evaluate the health status of forests, plantations and crops. Conventional methods of measuring plant traits (e.g. wet chemistry), although accurate, are inefficient and costly when applied over large areas or with intensive sampling. Spectroscopic methods, as used in the food industry and mineralogy, are nowadays applied to identify plant traits, however, most studies analysed visible to near infrared, while infrared spectra of longer wavelengths have been little used for identifying the spectral differences between plant species. This study measured the infrared spectra (1.4-16.0 μm) on individual, fresh leaves of 19 species (from herbaceous to woody species), as well as 14 leaf traits for each leaf. The results describe at which wavelengths in the infrared the leaves' spectra can differentiate most effectively between these plant species. A Quadratic Discrimination Analysis (QDA) shows that using five bands in the SWIR or the LWIR is enough to accurately differentiate these species (Kappa: 0.93, 0.94 respectively), while the MWIR has a lower classification accuracy (Kappa: 0.84). This study also shows that in the infrared spectra of fresh leaves, the identified species-specific features are correlated with leaf traits as well as changes in their values. Spectral features in the SWIR (1.66, 1.89 and 2.00 μm) are common to all species and match the main features of pure cellulose and lignin spectra. The depth of these features varies with changes of cellulose and leaf water content and can be used to differentiate species in this region. In the MWIR and LWIR, the absorption spectra of leaves are formed by key species-specific traits including lignin, cellulose, water, nitrogen and leaf thickness. The connection found in this study between leaf traits, features and spectral signatures are novel tools to assist when identifying plant species by spectroscopy and remote sensing.

Analytic calculations of anharmonic infrared and Raman vibrational spectra

PubMed Central

Louant, Orian; Ruud, Kenneth

2016-01-01

Using a recently developed recursive scheme for the calculation of high-order geometric derivatives of frequency-dependent molecular properties [Ringholm et al., J. Comp. Chem., 2014, 35, 622], we present the first analytic calculations of anharmonic infrared (IR) and Raman spectra including anharmonicity both in the vibrational frequencies and in the IR and Raman intensities. In the case of anharmonic corrections to the Raman intensities, this involves the calculation of fifth-order energy derivatives—that is, the third-order geometric derivatives of the frequency-dependent polarizability. The approach is applicable to both Hartree–Fock and Kohn–Sham density functional theory. Using generalized vibrational perturbation theory to second order, we have calculated the anharmonic infrared and Raman spectra of the non- and partially deuterated isotopomers of nitromethane, where the inclusion of anharmonic effects introduces combination and overtone bands that are observed in the experimental spectra. For the major features of the spectra, the inclusion of anharmonicities in the calculation of the vibrational frequencies is more important than anharmonic effects in the calculated infrared and Raman intensities. Using methanimine as a trial system, we demonstrate that the analytic approach avoids errors in the calculated spectra that may arise if numerical differentiation schemes are used. PMID:26784673

The Mid-Infrared Transmission Spectra of Antarctic Ureilites

NASA Technical Reports Server (NTRS)

Sandford, Scott A.

1993-01-01

The mid-infrared (4000-450 1/cm; 2.5-22.2 micron) transmission spectra of seven Antarctic ureilites and 10 Antarctic H-5 ordinary chondrites are presented. The ureilite spectra show a number of absorption bands, the strongest of which is a wide, complex feature centered near 1000 1/cm (10 micron) due to Si-O stretching vibrations in silicates. The profiles and positions of the substructure in this feature indicate that Mg-rich olivines and pyroxenes are the main silicates responsible. The relative abundances of these two minerals, as inferred from the spectra, show substantial variation from meteorite to meteorite, but generally indicate olivine is the most abundant (olivine:pyroxene = 60:40 to 95:5). Both the predominance of olivine and the variable olivine-to-pyroxene ratio are consistent with the known composition and heterogeneity of ureilites. The H-5 ordinary chondrites spanned a range of weathering classes and were used to provide a means of addressing the extent to which the ureilite spectra may have been altered by weathering processes. It was found that, while weathering of these meteorites produces some weak bands due to the formation of small amounts of carbonates and hydrates, the profile of the main silicate feature has been little affected by Antarctic exposure in the meteorites studied here. The mid-infrared ureilite spectra provide an additional means of testing potential asteroidal parent bodies for the ureilites. At present, the best candidates include the subset of S-type asteroids having low albedos and weak absorption features in the near infrared.

Far infrared spectra of solid state aliphatic amino acids in different protonation states

NASA Astrophysics Data System (ADS)

Trivella, Aurélien; Gaillard, Thomas; Stote, Roland H.; Hellwig, Petra

2010-03-01

Far infrared spectra of zwitterionic, cationic, and anionic forms of aliphatic amino acids in solid state have been studied experimentally. Measurements were done on glycine, L-alanine, L-valine, L-leucine, and L-isoleucine powder samples and film samples obtained from dried solutions prepared at pH ranging from 1 to 13. Solid state density functional theory calculations were also performed, and detailed potential energy distributions were obtained from normal mode results. A good correspondence between experimental and simulated spectra was achieved and this allowed us to propose an almost complete band assignment for the far infrared spectra of zwitterionic forms. In the 700-50 cm-1 range, three regions were identified, each corresponding to a characteristic set of normal modes. A first region between 700 and 450 cm-1 mainly contained the carboxylate bending, rocking, and wagging modes as well as the ammonium torsional mode. The 450-250 cm-1 region was representative of backbone and sidechain skeletal bending modes. At last, the low wavenumber zone, below 250 cm-1, was characteristic of carboxylate and skeletal torsional modes and of lattice modes. Assignments are also proposed for glycine cationic and anionic forms, but could not be obtained for all aliphatic amino acids due to the lack of structural data. This work is intended to provide fundamental information for the understanding of peptides vibrational properties.

Effect of pressure on infrared spectra of ice 7

NASA Technical Reports Server (NTRS)

Holzapfel, W. B.; Seiler, B.; Nicol, M.

1983-01-01

The effect of pressure on the infrared spectra of H2O and D2O ice VII was studied at room temperature and pressures between 2 and 15 GPa with a Fourier transform infrared spectrometer and a diamond anvil high pressure cell. Two librational modes, one bending mode, and various overtone bands are well resolved. The stretching modes, nu sub 1 and nu sub 3 are poorly resolved due to overlap with diamond window absorption. Differences between the spectra of H2O and D2O are discussed.

Isosbestics in Infrared Aerosol Spectra: Proposed Applications for Remote Sensing.

DTIC Science & Technology

1989-04-01

droplet solutions and chemical reactions if the complex indices of refraction are known. The technique seems most applicable in the Rayleigh regime. Remote ... sensing , Isosbestics, Infrared, Infrared spectra, Atmosphere, Water, Aerosols, Rayleigh regime.

Visible/near-infrared spectra of experimentally shocked plagioclase feldspars

USGS Publications Warehouse

Johnson, J. R.; Horz, F.

2003-01-01

High shock pressures cause structural changes in plagioclase feldspars such as mechanical fracturing and disaggregation of the crystal lattice at submicron scales, the formation of diaplectic glass (maskelynite), and genuine melting. Past studies of visible/ near-infrared spectra of shocked feldspars demonstrated few spectral variations with pressure except for a decrease in the depth of the absorption feature near 1250-1300 nm and an overall decrease in reflectance. New visible/near-infrared spectra (400-2500 nm) of experimentally shocked (17-56 GPa) albite- and anorthite-rich rock powders demonstrate similar trends, including the loss of minor hydrated mineral bands near 1410, 1930, 2250, and 2350 nm. However, the most interesting new observations are increases in reflectance at intermediate pressures, followed by subsequent decreases in reflectance at higher pressures. The amount of internal scattering and overall sample reflectance is controlled by the relative proportions of micro-fractures, submicron grains, diaplectic glass, and melts formed during shock metamorphism. We interpret the observed reflectance increases at intermediate pressures to result from progressively larger proportions of submicron feldspar grains and diaplectic glass. The ensuing decreases in reflectance occur after diaplectic glass formation is complete and the proportion of genuine melt inclusions increases. The pressure regimes over which these reflectance variations occur differ between albite and anorthite, consistent with thermal infrared spectra of these samples and previous studies of shocked feldspars. These types of spectral variations associated with different peak shock pressures should be considered during interpretation and modeling of visible/near-infrared remotely sensed spectra of planetary and asteroidal surfaces.

Quantification of HCl from high-resolution, ground-based, infrared solar spectra in the 3000 per cm region

NASA Technical Reports Server (NTRS)

Goldman, A.; Murcray, F. J.; Blatherwick, R. D.; Murcray, D. G.

1986-01-01

Recent ground-based infrared solar spectra at 0.02 per cm resolution in the 3000 per cm region have been analyzed for the atmospheric content of HCl. Nonlinear spectral least-squares fitting applied to spectra obtained at several zenith angles shows little sensitivity of the results to tropospheric HCl but provides an accurate measurement of the total column amount.

Availability of a library of infrared (2.1-25.0 microns) mineral spectra

NASA Technical Reports Server (NTRS)

Salisbury, John W.; Vergo, Norma; Walter, Louis S.

1989-01-01

All previously published libraries of infrared mineral spectra are in the form of transmitance. Reflectance spectra are, however, more useful for remote sensing and some potential laboratory applications, such as the use of an infrared microscope for mineral identification on polished sections. This note points out that construction of a new library of infrared (2.1-25.0 microns) mineral spectra is in progress. Both transmittance and reflectance measurements of a selection of 63 different, well-characterized minerals have been published to date. These data are available in both hard copy and digital form.

Transition probabilities of Ce I obtained from Boltzmann analysis of visible and near-infrared emission spectra

NASA Astrophysics Data System (ADS)

Nitz, D. E.; Curry, J. J.; Buuck, M.; DeMann, A.; Mitchell, N.; Shull, W.

2018-02-01

We report radiative transition probabilities for 5029 emission lines of neutral cerium within the wavelength range 417-1110 nm. Transition probabilities for only 4% of these lines have been previously measured. These results are obtained from a Boltzmann analysis of two high resolution Fourier transform emission spectra used in previous studies of cerium, obtained from the digital archives of the National Solar Observatory at Kitt Peak. The set of transition probabilities used for the Boltzmann analysis are those published by Lawler et al (2010 J. Phys. B: At. Mol. Opt. Phys. 43 085701). Comparisons of branching ratios and transition probabilities for lines common to the two spectra provide important self-consistency checks and test for the presence of self-absorption effects. Estimated 1σ uncertainties for our transition probability results range from 10% to 18%.

The anharmonic quartic force field infrared spectra of three polycyclic aromatic hydrocarbons: Naphthalene, anthracene, and tetracene.

PubMed

Mackie, Cameron J; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Buma, Wybren Jan; Lee, Timothy J; Tielens, Alexander G G M

2015-12-14

Current efforts to characterize and study interstellar polycyclic aromatic hydrocarbons (PAHs) rely heavily on theoretically predicted infrared (IR) spectra. Generally, such studies use the scaled harmonic frequencies for band positions and double harmonic approximation for intensities of species, and then compare these calculated spectra with experimental spectra obtained under matrix isolation conditions. High-resolution gas-phase experimental spectroscopic studies have recently revealed that the double harmonic approximation is not sufficient for reliable spectra prediction. In this paper, we present the anharmonic theoretical spectra of three PAHs: naphthalene, anthracene, and tetracene, computed with a locally modified version of the SPECTRO program using Cartesian derivatives transformed from Gaussian 09 normal coordinate force constants. Proper treatments of Fermi resonances lead to an impressive improvement on the agreement between the observed and theoretical spectra, especially in the C-H stretching region. All major IR absorption features in the full-scale matrix-isolated spectra, the high-temperature gas-phase spectra, and the most recent high-resolution gas-phase spectra obtained under supersonically cooled molecular beam conditions in the CH-stretching region are assigned.

The anharmonic quartic force field infrared spectra of three polycyclic aromatic hydrocarbons: Naphthalene, anthracene, and tetracene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackie, Cameron J., E-mail: mackie@strw.leidenuniv.nl; Candian, Alessandra; Tielens, Alexander G. G. M.

2015-12-14

Current efforts to characterize and study interstellar polycyclic aromatic hydrocarbons (PAHs) rely heavily on theoretically predicted infrared (IR) spectra. Generally, such studies use the scaled harmonic frequencies for band positions and double harmonic approximation for intensities of species, and then compare these calculated spectra with experimental spectra obtained under matrix isolation conditions. High-resolution gas-phase experimental spectroscopic studies have recently revealed that the double harmonic approximation is not sufficient for reliable spectra prediction. In this paper, we present the anharmonic theoretical spectra of three PAHs: naphthalene, anthracene, and tetracene, computed with a locally modified version of the SPECTRO program using Cartesianmore » derivatives transformed from Gaussian 09 normal coordinate force constants. Proper treatments of Fermi resonances lead to an impressive improvement on the agreement between the observed and theoretical spectra, especially in the C–H stretching region. All major IR absorption features in the full-scale matrix-isolated spectra, the high-temperature gas-phase spectra, and the most recent high-resolution gas-phase spectra obtained under supersonically cooled molecular beam conditions in the CH-stretching region are assigned.« less

Improved quantitative analysis of spectra using a new method of obtaining derivative spectra based on a singular perturbation technique.

PubMed

Li, Zhigang; Wang, Qiaoyun; Lv, Jiangtao; Ma, Zhenhe; Yang, Linjuan

2015-06-01

Spectroscopy is often applied when a rapid quantitative analysis is required, but one challenge is the translation of raw spectra into a final analysis. Derivative spectra are often used as a preliminary preprocessing step to resolve overlapping signals, enhance signal properties, and suppress unwanted spectral features that arise due to non-ideal instrument and sample properties. In this study, to improve quantitative analysis of near-infrared spectra, derivatives of noisy raw spectral data need to be estimated with high accuracy. A new spectral estimator based on singular perturbation technique, called the singular perturbation spectra estimator (SPSE), is presented, and the stability analysis of the estimator is given. Theoretical analysis and simulation experimental results confirm that the derivatives can be estimated with high accuracy using this estimator. Furthermore, the effectiveness of the estimator for processing noisy infrared spectra is evaluated using the analysis of beer spectra. The derivative spectra of the beer and the marzipan are used to build the calibration model using partial least squares (PLS) modeling. The results show that the PLS based on the new estimator can achieve better performance compared with the Savitzky-Golay algorithm and can serve as an alternative choice for quantitative analytical applications.

Gas-phase infrared spectra of vinyl selenol and vinyl tellurol.

PubMed

Benidar, Abdessamad; Khater, Brahim; Guillemin, Jean-Claude; Gámez, José A; Yáñez, Manuel

2009-11-19

The infrared spectra (3500-500 cm(-1)) of gaseous vinyl selenol and vinyl tellurol have been recorded at 0.1 cm(-1) resolution. For the latter the spectra were obtained at room temperature, but for the former a temperature of -40 degrees C was required because of the chemical instability of vinyl selenol at room temperature. To compensate the very weak vapor pressure of vinyl tellurol at room temperature, a long optical path up to 136 m was necessary to record its spectrum. B3LYP density functional theory (DFT) calculations have been performed to assign the different absorption bands. Since an unambiguous assignment of the absorption bands requires a precise knowledge on the relative abundance of the syn and gauche rotamers of these compounds, their relative energies and their anharmonic vibrational frequencies were obtained using a very extended Def2-QZVP basis set. Two rotamers, the syn, which is planar, and a nonplanar gauche, were found to be local minima for both compounds. The gauche rotamer presents two degenerate conformers, which differ by the position of the SeH (TeH) hydrogen atom above or below the molecular plane. Our theoretical results are in good agreement with the main features of the experimental spectra. Fundamental bands and some combination bands of vinyl selenol and vinyl tellurol were assigned and compared with those of vinyl alcohol and vinyl thiol, whose spectra had been reported previously in the literature.

Gas-Phase Infrared Spectra of Vinyl Selenol and Vinyl Tellurol

NASA Astrophysics Data System (ADS)

Benidar, Abdessamad; Khater, Brahim; Guillemin, Jean-Claude; Gámez, José A.; Yáñez, Manuel

2009-10-01

The infrared spectra (3500-500 cm-1) of gaseous vinyl selenol and vinyl tellurol have been recorded at 0.1 cm-1 resolution. For the latter the spectra were obtained at room temperature, but for the former a temperature of -40 °C was required because of the chemical instability of vinyl selenol at room temperature. To compensate the very weak vapor pressure of vinyl tellurol at room temperature, a long optical path up to 136 m was necessary to record its spectrum. B3LYP density functional theory (DFT) calculations have been performed to assign the different absorption bands. Since an unambiguous assignment of the absorption bands requires a precise knowledge on the relative abundance of the syn and gauche rotamers of these compounds, their relative energies and their anharmonic vibrational frequencies were obtained using a very extended Def2-QZVP basis set. Two rotamers, the syn, which is planar, and a nonplanar gauche, were found to be local minima for both compounds. The gauche rotamer presents two degenerate conformers, which differ by the position of the SeH (TeH) hydrogen atom above or below the molecular plane. Our theoretical results are in good agreement with the main features of the experimental spectra. Fundamental bands and some combination bands of vinyl selenol and vinyl tellurol were assigned and compared with those of vinyl alcohol and vinyl thiol, whose spectra had been reported previously in the literature.

Automatic classification of spectra from the Infrared Astronomical Satellite (IRAS)

NASA Technical Reports Server (NTRS)

Cheeseman, Peter; Stutz, John; Self, Matthew; Taylor, William; Goebel, John; Volk, Kevin; Walker, Helen

1989-01-01

A new classification of Infrared spectra collected by the Infrared Astronomical Satellite (IRAS) is presented. The spectral classes were discovered automatically by a program called Auto Class 2. This program is a method for discovering (inducing) classes from a data base, utilizing a Bayesian probability approach. These classes can be used to give insight into the patterns that occur in the particular domain, in this case, infrared astronomical spectroscopy. The classified spectra are the entire Low Resolution Spectra (LRS) Atlas of 5,425 sources. There are seventy-seven classes in this classification and these in turn were meta-classified to produce nine meta-classes. The classification is presented as spectral plots, IRAS color-color plots, galactic distribution plots and class commentaries. Cross-reference tables, listing the sources by IRAS name and by Auto Class class, are also given. These classes show some of the well known classes, such as the black-body class, and silicate emission classes, but many other classes were unsuspected, while others show important subtle differences within the well known classes.

Multivariate classification of infrared spectra of cell and tissue samples

DOEpatents

Haaland, David M.; Jones, Howland D. T.; Thomas, Edward V.

1997-01-01

Multivariate classification techniques are applied to spectra from cell and tissue samples irradiated with infrared radiation to determine if the samples are normal or abnormal (cancerous). Mid and near infrared radiation can be used for in vivo and in vitro classifications using at least different wavelengths.

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) has been returned to NASA Spacecraft Hangar AE from the launch pad. It will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) has been returned to NASA Spacecraft Hangar AE from the launch pad. It will remain in the clean room until it returns to the pad in early August. 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.

Interference correction by extracting the information of interference dominant regions: Application to near-infrared spectra

NASA Astrophysics Data System (ADS)

Bi, Yiming; Tang, Liang; Shan, Peng; Xie, Qiong; Hu, Yong; Peng, Silong; Tan, Jie; Li, Changwen

2014-08-01

Interference such as baseline drift and light scattering can degrade the model predictability in multivariate analysis of near-infrared (NIR) spectra. Usually interference can be represented by an additive and a multiplicative factor. In order to eliminate these interferences, correction parameters are needed to be estimated from spectra. However, the spectra are often mixed of physical light scattering effects and chemical light absorbance effects, making it difficult for parameter estimation. Herein, a novel algorithm was proposed to find a spectral region automatically that the interesting chemical absorbance and noise are low, that is, finding an interference dominant region (IDR). Based on the definition of IDR, a two-step method was proposed to find the optimal IDR and the corresponding correction parameters estimated from IDR. Finally, the correction was performed to the full spectral range using previously obtained parameters for the calibration set and test set, respectively. The method can be applied to multi target systems with one IDR suitable for all targeted analytes. Tested on two benchmark data sets of near-infrared spectra, the performance of the proposed method provided considerable improvement compared with full spectral estimation methods and comparable with other state-of-art methods.

RER SPECTRA OBTAINED WITH A MULTICRYSTAL SPECTROMETER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Austin, W.E.; Champion, W.R.

1959-11-01

Relative gamma spectra were obtained twenty feet from the Hadiation Effects Reactor. The measurements were made using a multicry-stal spectrometer. This design incorporates pair and anticompton spectrometers in combination. Two reactor configurations were used; with shield tanks empty- and water filled. The spectra were obtained before the fuel elements were run at high power. Consequently very little of the fission product spectrum is tntermined. (J.R.D.)

Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

NASA Astrophysics Data System (ADS)

Thompson, Grant D.; Levenson, N. A.; Sirocky, M. M.; Uddin, S.

2007-12-01

Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars. We acknowledge work supported by the NSF under grant number 0237291.

Availability of a library of infrared (2.1-25.0 μm) mineral spectra

USGS Publications Warehouse

Salisbury, John W.; Walter, Louis S.; Vergo, Norma

1989-01-01

All previously published libraries of infrared mineral spectra are in the form of transmittance.  Reflectance spectra are, however, more useful for remote sensing and some potential laboratory applications, such as the use of an infrared microscope for mineral identification on polished sections. This note points out that construction of a new library of infrared (2.1-25.0 μm) mineral spectra is in progress. Both transmittance and reflectance measurements of a selection of 63 different, well-characteized minerals have been published to date. These data are available in both hard copy and digital form.

High-pressure Infrared Spectra of Tal and Lawsonite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott,H.; Liu, Z.; Hemley, R.

2007-01-01

We present high-pressure infrared spectra of two geologically important hydrous minerals: talc, Mg3Si4O10(OH)2 and lawsonite, CaAl2Si2O7(OH)2{center_dot}H2O,{center_dot}at room temperature. For lawsonite, our data span the far infrared region from 150 to 550 cm-1 and extend to 25 GPa. We combine our new spectroscopic data with previously published high-pressure mid-infrared and Raman data to constrain the Gr{umlt u}neisen parameter and vibrational density of states under pressure. In the case of talc, we present high-pressure infrared data that span both the mid and far infrared from 150 to 3800 cm-1 covering lattice, silicate, and hydroxyl stretching vibrations to a maximum pressure of 30more » GPa. Both phases show remarkable metastability well beyond their nominal maximum thermodynamic stability at simultaneous high-pressure and high-temperature conditions.« less

Infrared absorption spectra of metal carbides, nitrides and sulfides

NASA Technical Reports Server (NTRS)

Kammori, O.; Sato, K.; Kurosawa, F.

1981-01-01

The infrared absorption spectra of 12 kinds of metal carbides, 11 kinds of nitrides, and 7 kinds of sulfides, a total of 30 materials, were measured and the application of the infrared spectra of these materials to analytical chemistry was discussed. The measurements were done in the frequency (wave length) range of (1400 to 400/cm (7 to 25 mu). The carbides Al4C3, B4C, the nitrides AlN, BN, Si3N4, WB, and the sulfides Al2S3, FeS2, MnS, NiS and PbS were noted to have specific absorptions in the measured region. The sensitivity of Boron nitride was especially good and could be detected at 2 to 3 micrograms in 300 mg of potassium bromide.

Theoretical infrared and electronic absorption spectra of C16H10 isomers, their ions and doubly ions

NASA Astrophysics Data System (ADS)

Naganathappa, Mahadevappa; Chaudhari, Ajay

2012-09-01

Polycyclic aromatic hydrocarbons (PAHs) or PAH-related molecules are considered to be responsible for the unidentified infrared (UIR) emission features at 3.3, 6.2, 7.7, 8.6 and 11.2 μm. However, the exact identification of PAH or PAH-related molecules is difficult. There have been several investigations on the spectroscopic characterization of PAH molecules. But none of them compared the spectra of isomers of PAHs, which might have help in the identification of the UIR emission features. This work presents the infrared and electronic absorption spectra of isomers of C16H10. The aim of the present work is to compare infrared and electronic absorption spectra of four isomers of C16H10 PAH viz. pyrene, aceanthrylene, acephenanthrylene and fluoranthene, their ions and doubly ions. We also compare the spectra of pyrene in the gas-phase and in H2O ice. We have used the density functional theory with B3LYP exchange and correlation functional and 6-311++g** basis set to study the infrared spectra. The time-dependent density functional theory (TDDFT) has been used to obtain the electronic absorption spectra. Significant difference in the CC stretching, CH in-plane bending and CH out-of-plane bending vibration modes is observed for the isomers of C16H10 whereas there is no large difference in the CH stretching vibration band. A significant change in the vibrational band is observed for pyrene in H2O ice compared to gas-phase pyrene. Though isomers of C16H10 PAH have the same number of carbon and hydrogen atoms, their spectroscopic characteristics are different. This study should help in identifying the isomers of C16H10, their ions and doubly cation in the interstellar medium.

AN ATLAS OF BRIGHT STAR SPECTRA IN THE NEAR-INFRARED FROM CASSINI-VIMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Paul N.; Tuthill, Peter G.; Nicholson, Philip D.

2015-12-15

We present the Cassini Atlas Of Stellar Spectra (CAOSS), comprised of near-infrared, low-resolution spectra of bright stars recovered from space-based observations by the Cassini spacecraft. The 65 stellar targets in the atlas are predominately M, K, and S giants. However, it also contains spectra of other bright nearby stars including carbon stars and main-sequence stars from A to F. The spectra presented are free of all spectral contamination caused by the Earth's atmosphere, including the detrimental telluric molecular bands which put parts of the near-infrared spectrum out of reach of terrestrial observations. With a single instrument, a spectro-photometric data set is recoveredmore » that spans the near-infrared from 0.8 to 5.1 μm with spectral resolution ranging from R = 53.5 to R = 325. Spectra have been calibrated into absolute flux units after careful characterization of the instrumental spectral efficiency. Spectral energy distributions for most stars match closely with literature values. All final data products have been made available online.« less

Water Vapor in Titan’s Stratosphere from Cassini CIRS Far-infrared Spectra

NASA Astrophysics Data System (ADS)

Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bézard, B.; de Kok, R.; Lellouch, E.; Irwin, P. G. J.; Flasar, F. M.; Bampasidis, G.

2012-10-01

We will report the measurement of water vapor in Titan’s stratosphere (Cottini et al. 2012), using the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al. 2004). CIRS senses water emissions in the far infrared spectral region near 50 microns, which we have modeled using a radiative transfer code (NEMESIS, Irwin et al. 2008). From the analysis of nadir spectra we have derived a mixing ratio of 0.14 ± 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7±1.3 × 1014 molecules/cm2. In the latitude range 80°S to 30°N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 ± 0.04 ppb at an altitude of 115 km and 0.45 ± 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by previous photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan’s lower stratosphere. Valeria Cottini is supported by the NASA Postdoctoral Program. References Cottini V. et al., 2012. Detection of water vapor in Titan’s atmosphere from Cassini/CIRS infrared spectra. Icarus, 220, 2, 855-862 Flasar, F.M., and 44 colleagues, 2004. Exploring the Saturn system in the thermal infrared: The Composite Infrared Spectrometer. Space Sci. Rev., 115, 169-297 Irwin, P.G.J., et al., 2008. The NEMESIS planetary atmosphere radiative transfer and retrieval tool. J. Quant. Spectrosc. Radiat. Trans., 109, 1136-1150.

Prognosis of chronic lymphocytic leukemia from infrared spectra of lymphocytes

NASA Astrophysics Data System (ADS)

Schultz, Christian P.; Liu, Kan-Zhi; Johnston, James B.; Mantsch, Henry H.

1997-06-01

Peripheral mononuclear cells obtained from blood of normal individuals and from patients with chronic lymphocytic leukemia (CLL) were investigated by infrared spectroscopy and multivariate statistical analysis. Not only are the spectra of CLL cells different from those of normal cells, but hierarchical clustering also separated the CLL cells into a number of subclusters, based on their different DNA content, a fact which may provide a useful diagnostic tool for staging (progression of the disease) and multiple clone detection. Moreover, there is evidence for a correlation between the increased amount of DNA in the CLL cells and the in-vivo doubling time of the lymphocytes in a given patient.

Untangling the Herman-infrared spectra of nitrogen atmospheric-pressure dielectric-barrier discharge

NASA Astrophysics Data System (ADS)

Čermák, Peter; Annušová, Adriana; Rakovský, Jozef; Martišovitš, Viktor; Veis, Pavel

2018-05-01

This study presents the first application of the N2 Herman-infrared (HIR) ro-vibrational model for the metrology of the atmospheric-pressure dielectric-barrier discharge. Our recent findings of suitable conditions for observation of the unperturbed HIR system (Annušová et al Contrib. Plasma Phys. 2017) gave us the opportunity to develop and test a numerical representation of this complex system composed of 75 branches. Commonly, the HIR covers a part of the near infrared spectra (690–850 nm) with its bands mixed with the N2 first positive system (1PS), which hinders applications of these systems for optical metrology of the discharge. In this work, we present a complex ro-vibrational model of the 1PS and HIR systems, which allowed us to untangle their spectra and retrieve the rotational temperature and vibrational populations of the systems for the first time. The latter was achieved by coupling the PGHOPHER simulation package with molecular constants obtained from high-resolution experiments. To test the model, the results and precision were compared to the retrievals based on the models of the NO γ and N2 second positive systems using the LIFBASE and SPECAIR programs, respectively.

Influence of temperature on water and aqueous glucose absorption spectra in the near- and mid-infrared regions at physiologically relevant temperatures.

PubMed

Jensen, Peter Snoer; Bak, Jimmy; Andersson-Engels, Stefan

2003-01-01

Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000-950 cm-1 were measured in the temperature range 30-42 degrees C in steps of 2 degrees C. Measurements were carried out with an FT-IR spectrometer and a variable pathlength transmission cell controlled within 0.02 degree C. Pathlengths of 50 microns and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37 degrees C water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between. On the basis of these spectra, prospects for and limitations on data analysis for infrared diagnostic methods are discussed. As an example, the absorptive properties of glucose were studied in the same temperature range in order to determine the effect of temperature on the spectral shape of glucose. The change in water absorption associated with the addition of glucose has also been studied. An estimate of these effects is given and is related to the expected level of infrared signals from glucose in humans.

Infrared spectra in monitoring biochemical parameters of human blood

NASA Astrophysics Data System (ADS)

Prabhakar, S.; Jain, N.; Singh, R. A.

2012-05-01

Infrared spectroscopy is gaining recognition as a promising method. The infrared spectra of selected regions (2000-400cm-1) of blood tissue samples are reported. Present study related to the role of spectral peak fitting in the study of human blood and quantitative interpretations of infrared spectra based on chemometrics. The spectral variations are interpreted in terms of the biochemical and pathological processes involved. The mean RNA/DNA ratio of fitted intensities and analytical area as calculated from the transmittance peaks at 1121cm-1/1020cm-1 is found to be 0.911A.U and 2.00A.U. respectively. The ratio of 1659cm-1/1544cm-1 (amide-I/amide-II) bands is found to shed light on the change in the DNA content. The ratio of amide-I/amide-II is almost unity (≈1.054) for blood spectra. The deviation from unity is an indication of DNA absorption from the RBC cells. The total phosphate content has found to be 25.09A.U. The level for glycogen/phosphate ratio (areas under peaks 1030cm-1/1082cm-1) is found to be 0.286A.U. The ratio of unsaturated and saturated carbonyl compounds (C=O) in blood samples is in form of esters and the analytical areas under the spectral peaks at 1740cm-1 and 1731cm-1 for unsaturated esters and saturated esters respectively found to be 0.618A.U.

Comparison of visible and near-infrared reflectance spectra of CM2 carbonaceous chondrites and primitive asteroids

NASA Technical Reports Server (NTRS)

Vilas, F.; Hiroi, T.; Zolensky, M. E.

1993-01-01

Spectra of primitive asteroids (defined as C, P, and D classes and associated subclasses) were compared to the limited number of spectra of CM2 carbonaceous chondrites. An absorption feature located at 0.7 microns attributed to an Fe(+2) - Fe(+3) charge transfer absorption in iron oxides in phyllosilicates is apparent in some of the CM2 carbonaceous chondrite spectra and many of the asteroid spectra. Sawyer found a correlation between the area of the 0.7 micron feature and the mean semimajor axis of the asteroids. Spectra of a larger sample of carbonaceous chondrites, including 7 CM2 chondrites, covering a spectral interval of 0.30-2.5 microns were recently obtained using the Relab instrument at Brown University. These spectra were compared with spectrophotometric asteroid observations in a separate abstract. Those spectra of CM2 chondrites were isolated into the UV, visible and near-infrared spectral regions in order to compare them with high-quality narrowband reflectance spectra.

Infrared and visible absolute and difference spectra of bacteriorhodopsin photocycle intermediates.

PubMed

Hendler, Richard W; Meuse, Curtis W; Braiman, Mark S; Smith, Paul D; Kakareka, John W

2011-09-01

We have used new kinetic fitting procedures to obtain infrared (IR) absolute spectra for intermediates of the main bacteriorhodopsin (bR) photocycle(s). The linear-algebra-based procedures of Hendler et al. (J. Phys. Chem. B, 105, 3319-3228 (2001)) for obtaining clean absolute visible spectra of bR photocycle intermediates were adapted for use with IR data. This led to isolation, for the first time, of corresponding clean absolute IR spectra, including the separation of the M intermediate into its M(F) and M(S) components from parallel photocycles. This in turn permitted the computation of clean IR difference spectra between pairs of successive intermediates, allowing for the most rigorous analysis to date of changes occurring at each step of the photocycle. The statistical accuracy of the spectral calculation methods allows us to identify, with great confidence, new spectral features. One of these is a very strong differential IR band at 1650 cm(-1) for the L intermediate at room temperature that is not present in analogous L spectra measured at cryogenic temperatures. This band, in one of the noisiest spectral regions, has not been identified in any previous time-resolved IR papers, although retrospectively it is apparent as one of the strongest L absorbance changes in their raw data, considered collectively. Additionally, our results are most consistent with Arg82 as the primary proton-release group (PRG), rather than a protonated water cluster or H-bonded grouping of carboxylic residues. Notably, the Arg82 deprotonation occurs exclusively in the M(F) pathway of the parallel cycles model of the photocycle. © 2011 Society for Applied Spectroscopy

Field Red Horizontal Branch Star Chemical Compositions from High Resolution Infrared Spectra

NASA Astrophysics Data System (ADS)

Sneden, Chris; Afsar, Melike; Bozkurt, Zeynep; Bocek-Topcu, Gamze; Mace, Gregory N.; Kim, Hwihyun; Kaplan, Kyle; Kidder, Benjamin; McLane, Jacob

2017-06-01

We have observed three field red horizontal branch stars with the Immersion Grating Infrared Spectrograph (IGRINS). The high resolution (R~45000) high signal-to-noise (S/N > 200) spectra obtained with IGRINS cover the complete H-band (1.50-1.80 micron) and K-band (1.90-2.45 micron). We analyzed hundreds of lines of the ubiquitous OH, CN, and CO molecular bands, and found more than 80 lines of atomic species that were useful for abundance work. A combination of good laboratory transition probabilities (when available) and ones derived from reverse solar analyses were employed. Our transition data were checked through studies of the Arcturus Atlas spectrum. We derived abundances from synthetic spectra instead of from equivalent widths. With IGRINS data we were able to extract metallicities and abundance ratios for more than 20 elements, including several not detectable or poorly represented in optical wavelength regions. Our abundances from IGRINS spectra are in excellent accord with those derived from optical spectrum studies. These results are directly applicable to calibrations of results from lower-resolution and/or S/N infrared spectral surveys. IGRINS observations will give high reolution spectroscopic access to heavily obscured normal red giants and other cool stars with unusual element mixes.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMT Project of KASI. Our project also has been supported by NSF grants AST~1211585 and AST~1616040, by the University of Texas Rex G. Baker, Jr. Centennial Research Endowment, and by The Scientific and Technological Research Council of Turkey (TUBITAK, project No. 112T929).

Hydrogen Dimers in Giant-planet Infrared Spectra

NASA Astrophysics Data System (ADS)

Fletcher, Leigh N.; Gustafsson, Magnus; Orton, Glenn S.

2018-03-01

Despite being one of the weakest dimers in nature, low-spectral-resolution Voyager/IRIS observations revealed the presence of (H2)2 dimers on Jupiter and Saturn in the 1980s. However, the collision-induced H2–H2 opacity databases widely used in planetary science have thus far only included free-to-free transitions and have neglected the contributions of dimers. Dimer spectra have both fine-scale structure near the S(0) and S(1) quadrupole lines (354 and 587 cm‑1, respectively), and broad continuum absorption contributions up to ±50 cm‑1 from the line centers. We develop a new ab initio model for the free-to-bound, bound-to-free, and bound-to-bound transitions of the hydrogen dimer for a range of temperatures (40–400 K) and para-hydrogen fractions (0.25–1.0). The model is validated against low-temperature laboratory experiments, and used to simulate the spectra of the giant planets. The new collision-induced opacity database permits high-resolution (0.5–1.0 cm‑1) spectral modeling of dimer spectra near S(0) and S(1) in both Cassini Composite Infrared Spectrometer observations of Jupiter and Saturn, and in Spitzer Infrared Spectrometer (IRS) observations of Uranus and Neptune for the first time. Furthermore, the model reproduces the dimer signatures observed in Voyager/IRIS data near S(0) on Jupiter and Saturn, and generally lowers the amount of para-H2 (and the extent of disequilibrium) required to reproduce IRIS observations.

The Effect of Chain Length on Mid-Infrared and Near-Infrared Spectra of Aliphatic 1-Alcohols.

PubMed

Kwaśniewicz, Michał; Czarnecki, Mirosław A

2018-02-01

Effect of the chain length on mid-infrared (MIR) and near-infrared (NIR) spectra of aliphatic 1-alcohols from methanol to 1-decanol was examined in detail. Of particular interest were the spectra-structure correlations in the NIR region and the correlation between MIR and NIR spectra of 1-alcohols. An application of two-dimensional correlation analysis (2D-COS) and chemometric methods provided comprehensive information on spectral changes in the data set. Principal component analysis (PCA) and cluster analysis evidenced that the spectra of methanol, ethanol, and 1-propanol are noticeably different from the spectra of higher 1-alcohols. The similarity between the spectra increases with an increase in the chain length. Hence, the most similar are the spectra of 1-nonanol and 1-decanol. Two-dimensional hetero-correlation analysis is very helpful for identification of the origin of bands and may guide selection of the best spectral ranges for the chemometric analysis. As shown, normalization of the spectra pronounces the intensity changes in various spectral regions and provides information not accessible from the raw data. The spectra of alcohols cannot be represented as a sum of the CH 3 , CH 2 , and OH group spectra since the OH group is involved in the hydrogen bonding. As a result, the spectral changes of this group are nonlinear and its spectral profile cannot be properly resolved. Finally, this work provides a lot of evidence that the degree of self-association of 1-alcohols decreases with the increase in chain length because of the growing meaning of the hydrophobic interactions. For butyl alcohol and higher 1-alcohols the hydrophobic interactions are more important than the OH OH interactions. Therefore, methanol, ethanol, and 1-propanol have unlimited miscibility with water, whereas 1-butanol and higher 1-alcohols have limited miscibility with water.

High Resolution Far-Infrared Spectra of Thiophosgene with a Synchrotron Source: The ν2 and ν4 Bands Near 500 cm-1

NASA Astrophysics Data System (ADS)

McKellar, A. R. W.; Billinghurst, B. E.

2010-02-01

Thiophosgene (Cl2CS) is a favorite model system for studies of vibrational dynamics. But there are no previous rotationally-resolved infrared studies because the spectra are very congested due to its (relatively) large mass and multiple isotopic species. Here we report a detailed gas-phase study of the ν2 (˜504 cm-1) and ν4 (˜471 cm-1) fundamental bands, based on spectra obtained at the Canadian Light Source far-infrared beamline using synchrotron radiation and a Bruker IFS125 FT spectrometer.

Production of Ti-C presolar carbide grain analogies and its infrared spectra

NASA Astrophysics Data System (ADS)

Kimura, Y.; Ikegami, A.; Tanigaki, T.; Ishikawa, M.; Sato, T.; Suzuki, H.; Kido, O.; Kaito, C.

The infrared emission of the circumstellar environment of carbon-rich stars and dense molecular cloud cores is believed to be dominated by the emissivity of carbon dust. The origins of absorption peaks will be identified on the basis of laboratory studies. Important factors in the determination of absorption features are size, shape and structure of the grain (Bohren and Huffman, 1983). Therefore, the production of presolar grain analogy is important for the identification of the observation spectra. Recently, we succeeded in the formation of Si-, Ti- and Zr-C grains of the order of 50 nm by advanced gas evaporation method. We have started to obtain characteristic data of carbide grains in laboratory experiments. The spectra from ultraviolet to infrared of samples embedded in KBr pellets are presented. In the present study, we will elucidate the correlation between the size of TiC grain or thickness of the carbon mantle layer and spectra of TiC core-carbon mantle grains. Because TiC is one of the candidates of 21 micron feature. The absorption peaks of TiC core (50 nm)-carbon mantle (2 nm) grains were found to be at 9.5 and 12.5 microns. When the thickness of the mantle layer increased to 15 nm, the peak at 12.5 microns disappeared and the peak at 9.5 microns was significantly weakened. These results are similar to the calculated result for SiC core-carbon mantle grains, i.e., increased thickness of the mantle layer weakens the spectrum intensity (Kozasa et al., 1996). The 20.1 micron absorption feature never appeared, even if the same size grains seen in meteorites were produced. Moreover, the infrared spectra were observed when the size of TiC grains was smaller than presolar grain. Carbon was deposited on the surface of Ti grains. Then, TiC nanocrystallites with the size of 2-3 nm were produced by the diffusion of Ti and/or carbon. The new absorption feature was appeared at 14 microns. The 12.5 micron absorption was hardly seen. If the samples are heated at 700

Vibron Solitons and Soliton-Induced Infrared Spectra of Crystalline Acetanilide

NASA Astrophysics Data System (ADS)

Takeno, S.

1986-01-01

Red-shifted infrared spectra at low temperatures of amide I (C=O stretching) vibrations of crystalline acetanilide measured by Careri et al. are shown to be due to vibron solitons, which are nonlinearity-induced localized modes of vibrons arising from their nonlinear interactions with optic-type phonons. A nonlinear eigenvalue equation giving the eigenfrequency of stationary solitons is solved approximately by introducing lattice Green's functions, and the obtained result is in good agreement with the experimental result. Inclusion of interactions with acoustic phonons yields the Debye-Waller factor in the zero-phonon line spectrum of vibron solitons, in a manner analogous to the case of impurity-induced localized harmonic phonon modes in alkali halides.

Far-infrared spectra of acetanilide revisited

NASA Astrophysics Data System (ADS)

Spire, A.; Barthes, M.; Kellouai, H.; De Nunzio, G.

2000-03-01

A new investigation of the temperature dependence of the far-infrared spectra of acetanilide and some isotopomers is presented. Four absorption bands are considered at 31, 42, 64, and 80 cm-1, and no significant change of their integrated intensity is observed when reducing the temperature. The temperature induced frequency shift values and other properties of these bands are consistent with an assignment as anharmonic lattice phonons. These results rule out the assignment of the 64, 80, and 106 cm-1 bands as normal modes of the polaronic excitation, as previously suggested.

A Simulation Program for Dynamic Infrared (IR) Spectra

ERIC Educational Resources Information Center

Zoerb, Matthew C.; Harris, Charles B.

2013-01-01

A free program for the simulation of dynamic infrared (IR) spectra is presented. The program simulates the spectrum of two exchanging IR peaks based on simple input parameters. Larger systems can be simulated with minor modifications. The program is available as an executable program for PCs or can be run in MATLAB on any operating system. Source…

Testing forward model against OCO-2 and TANSO-FTS/GOSAT observed spectra in near infrared range

NASA Astrophysics Data System (ADS)

Zadvornykh, Ilya V.; Gribanov, Konstantin G.

2015-11-01

An existing software package FIRE-ARMS (Fine InfraRed Explorer for Atmospheric Remote MeasurementS) was modified by embedding vector radiative transfer model VLIDORT. Thus the program tool includes both thermal (TIR) and near infrared (NIR) regions. We performed forward simulation of near infrared spectra on the top of the atmosphere for outgoing radiation accounting multiple scattering in cloudless atmosphere. Simulated spectra are compared with spectra measured by TANSO-FTS/GOSAT and OCO-2 in the condition of cloudless atmosphere over Western Siberia. NCEP/NCAR reanalysis data were used to complete model atmosphere.

Spectra Transfer Between a Fourier Transform Near-Infrared Laboratory and a Miniaturized Handheld Near-Infrared Spectrometer.

PubMed

Hoffmann, Uwe; Pfeifer, Frank; Hsuing, Chang; Siesler, Heinz W

2016-05-01

The aim of this contribution is to demonstrate the transfer of spectra that have been measured on two different laboratory Fourier transform near-infrared (FT-NIR) spectrometers to the format of a handheld instrument by measuring only a few samples with both spectrometer types. Thus, despite the extreme differences in spectral range and resolution, spectral data sets that have been collected and quantitative as well as qualitative calibrations that have been developed thereof, respectively, over a long period on a laboratory instrument can be conveniently transferred to the handheld system. Thus, the necessity to prepare completely new calibration samples and the effort required to develop calibration models when changing hardware platforms is minimized. The enabling procedure is based on piecewise direct standardization (PDS) and will be described for the data sets of a quantitative and a qualitative application case study. For this purpose the spectra measured on the FT-NIR laboratory spectrometers were used as "master" data and transferred to the "target" format of the handheld instrument. The quantitative test study refers to transmission spectra of three-component liquid solvent mixtures whereas the qualitative application example encompasses diffuse reflection spectra of six different current polymers. To prove the performance of the transfer procedure for quantitative applications, partial least squares (PLS-1) calibrations were developed for the individual components of the solvent mixtures with spectra transferred from the master to the target instrument and the cross-validation parameters were compared with the corresponding parameters obtained for spectra measured on the master and target instruments, respectively. To test the retention of the discrimination ability of the transferred polymer spectra sets principal component analyses (PCAs) were applied exemplarily for three of the six investigated polymers and their identification was demonstrated by

Generating the Infrared Spectra of Large Interstellar Molecules with Density Functional Theory

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Arnold, James (Technical Monitor)

1999-01-01

It is now possible to compute IR (infrared) spectra of large molecules with an accuracy of 30 per cm, or better, using density function theory. This is true for cations, anions, and neutrals. Thus it possible to generate synthetic IR spectra that can help interpret experimental spectra and fill in for missing experimental data. These synthetic spectra can be used as input into interstellar models. In addition to IR spectra, it is possible to compute energetic properties to help understand which molecules can be formed in the interstellar environment.

Using Molecular Modeling in Teaching Group Theory Analysis of the Infrared Spectra of Organometallic Compounds

ERIC Educational Resources Information Center

Wang, Lihua

2012-01-01

A new method is introduced for teaching group theory analysis of the infrared spectra of organometallic compounds using molecular modeling. The main focus of this method is to enhance student understanding of the symmetry properties of vibrational modes and of the group theory analysis of infrared (IR) spectra by using visual aids provided by…

Infrared spectra of molecules and materials of astrophysical interest

NASA Technical Reports Server (NTRS)

Durig, J. R.

1978-01-01

The Raman spectra of gaseous, liquid and solid, and infrared spectra of gaseous and solid isopropylamine-d sub 0 and -d sub 2 was investigated between 4000 and 50 cm superscript -1. Differences between the spectrum of the solid phase and that of the fluid phases were interpreted in terms of an equilibrium between low energy s-trans and high energy gauche conformers, and a complete vibrational assignment was proposed for the s-trans conformer. The far infrared spectra of the gaseous compounds contained bands due to the asymmetric amino and coupled methyl torsions; the assignment of these bands was aided by observation of a number of two quantum transitions for each vibrational mode. The asymmetric potential functions were calculated, which resulted in values for the enthalpy differences between conformers in the gaseous phase of 446 and 523 callmole for the sub 0 -d and -d sub 2 compounds, respectively. The methyl torsional potential function of isopropylamine-d sub 0 was calculated which led to a value for the barrier height to internal rotation of the methyl rotors of 4.23 + or - 0.06 kcal/mole. Values for the ideal gas thermodynamic functions were calculated over a range of temperatures.

Structural, optoelectronic, infrared and Raman spectra of orthorhombic SrSnO{sub 3} from DFT calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreira, E.; Henriques, J.M.; Azevedo, D.L.

2011-04-15

Orthorhombic SrSnO{sub 3} was investigated using density functional theory (DFT) considering both the local density and generalized gradient approximations, LDA and GGA, respectively. The electronic band structure, density of states, complex dielectric function, optical absorption, and the infrared and Raman spectra were computed. Calculated lattice parameters are close to the experimental measurements, and an indirect band gap E(S{yields}{Gamma})=1.97eV (2.27 eV) was obtained within the GGA (LDA) level of calculation. Effective masses for holes and electrons were estimated, being very anisotropic in comparison with similar results for orthorhombic CaSnO{sub 3}. The complex dielectric function and the optical absorption of SrSnO{sub 3}more » were shown to be sensitive to the plane of polarization of the incident light. The infrared spectrum between 100 and 600 cm{sup -1} was obtained, with its main peaks being assigned, and a nice agreement between experimental and theoretical peaks of the Raman spectrum of orthorhombic SrSnO{sub 3} was achieved. -- Graphical abstract: Orthorhombic SrSnO{sub 3}: a view of the unit cell (left) and plots showing the calculated and experimental Raman spectra (right). Display Omitted Research highlights: {yields} We have performed DFT calculations on orthorhombic SrSnO{sub 3} crystals, obtaining their structural, electronical and optical properties. {yields} An indirect band gap was obtained, and anisotropic effective masses were found for both electrons and holes. {yields} The complex dielectric function and the optical absorption of SrSnO{sub 3} were shown to be very sensitive to the plane of polarization of the incident light. {yields} The infrared spectrum between 100 and 600 cm{sup -1} was obtained, with its main peaks being assigned, and a nice agreement between experimental and theoretical peaks of the Raman spectrum was achieved.« less

First Infrared Predissociation Spectra of He-TAGGED Protonated Primary Alcohols at 4 K

NASA Astrophysics Data System (ADS)

Stoffels, Alexander; Redlich, Britta; Oomens, J.; Asvany, Oskar; Brünken, Sandra; Jusko, Pavol; Thorwirth, Sven; Schlemmer, Stephan

2015-06-01

Cryogenic multipole ion traps have become popular devices in the development of sensitive action-spectroscopic techniques. The low ion temperature leads to enhanced spectral resolution, and less congested spectra. In the early 2000s, a 22-pole ion trap was coupled to the Free-Electron Laser for Infrared eXperiments (FELIX), yielding infrared Laser Induced Reaction (LIR) spectra of the molecular ions C_2H_2+ and CH_5+. This pioneering work showed the great opportunities combining cold mass-selected molecular ions with widely tunable broadband IR radiation. In the past year a cryogenic (T>3.9 K) 22-pole ion trap designed and built in Cologne (FELion) has been successfully coupled to FELIX, which in its current configuration provides continuously tunable infrared radiation from 3 μm to 150 μm, hence allowing to probe characteristic vibrational spectra in the so-called "fingerprint region" with a sufficient spectral energy density also allowing for multiple photon processes (IR-MPD). Here we present the first infrared predissociation spectra of He-tagged protonated methanol and ethanol (MeOH_2+/EtOH_2+) stored at 4 K. These vibrational spectra were recorded with both a commercial OPO and FELIX, covering a total spectral range from 3700 wn to 550 wn at a spectral resolution of a few wn. The H-O-H stretching and bending modes clearly distinguish the protonated alcohols from their neutral analoga. For EtOH_2+, also IR-MPD spectra of the bare ion could be recorded. The symmetric and antisymmetric H-O-H stretching bands at around 3 μm show no significant shift within the given spectral resolution in comparison to those recorded with He predissociation, indicating a rather small perturbation caused by the attached He. The vibrational bands were assigned using quantum-chemical calculations on different levels of theory. The computed frequencies correspond favorably to the experimental spectra. Subsequent high resolution measurements could lead to a better structural

Aluminum oxide in stellar spectra - An infrared electronic transition

NASA Technical Reports Server (NTRS)

Luck, R. E.; Lambert, D. L.

1974-01-01

Review of recent research on the possibility of detecting the infrared electronic transition of aluminum oxide in the spectra of cool stars. It is shown that this transition may be of considerable significance for the study of Mira-type variables. Specific targets of further laboratory investigation of the transition are pointed out.

Atmospheric and surface properties of Mars obtained by infrared spectroscopy on Mariner 9

NASA Technical Reports Server (NTRS)

Conrath, B.; Curran, R. J.; Hanel, R.; Kunde, V. G.; Marguire, W.; Pearl, J.; Pirraglia, J. A.; Welker, J.; Burke, T.

1972-01-01

During the eleven month operational lifetime of Mariner 9, the infrared spectroscopy experiment obtained data over a large portion of Mars. Recently obtained spectra indicate that strong seasonal variations in the water vapor distribution over both polar regions occurred. The wettest atmospheric conditions observed so far contain 20 to 30 precipitable microns of water over the north polar cap during northern spring. A low resolution pressure map is presented which covers that portion of the planet between latitudes -60 deg and +25 deg. A more detailed study of the Coprates canyon indicates that at its lowest point the canyon floor must be at least 5 km below the rim. Applications of tidal theory to temperature fields derived from the spectra indicate diurnal surface pressure fluctuations of as much as 12 percent during the great dust storm of 1971-72. Qualitative arguments based on radiative transfer calculations for model dust clouds composed of spherical quartz particles suggest that particle radii during the storm were of the order of a few microns.

Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zapatero Osorio, M. R.; Béjar, V. J. S.; Ramírez, K. Peña, E-mail: mosorio@cab.inta-csic.es, E-mail: vbejar@iac.es, E-mail: karla.pena@uantof.cl

We have obtained low-resolution optical (0.7–0.98 μ m) and near-infrared (1.11–1.34 μ m and 0.8–2.5 μ m) spectra of 12 isolated planetary-mass candidates ( J = 18.2–19.9 mag) of the 3 Myr σ Orionis star cluster with the aim of determining the spectroscopic properties of very young, substellar dwarfs and assembling a complete cluster mass function. We have classified our targets by visual comparison with high- and low-gravity standards and by measuring newly defined spectroscopic indices. We derived L0–L4.5 and M9–L2.5 using high- and low-gravity standards, respectively. Our targets reveal clear signposts of youth, thus corroborating their cluster membership andmore » planetary masses (6–13 M {sub Jup}). These observations complete the σ Orionis mass function by spectroscopically confirming the planetary-mass domain to a confidence level of ∼75%. The comparison of our spectra with BT-Settl solar metallicity model atmospheres yields a temperature scale of 2350–1800 K and a low surface gravity of log g ≈ 4.0 [cm s{sup −2}], as would be expected for young planetary-mass objects. We discuss the properties of the cluster’s least-massive population as a function of spectral type. We have also obtained the first optical spectrum of S Ori 70, a T dwarf in the direction of σ Orionis. Our data provide reference optical and near-infrared spectra of very young L dwarfs and a mass function that may be used as templates for future studies of low-mass substellar objects and exoplanets. The extrapolation of the σ Orionis mass function to the solar neighborhood may indicate that isolated planetary-mass objects with temperatures of ∼200–300 K and masses in the interval 6–13 M {sub Jup} may be as numerous as very low-mass stars.« less

Spectra and structure of silicon containing compounds. XXXII. Raman and infrared spectra, conformational stability, vibrational assignment and ab initio calculations of n-propylsilane-d0 and Si-d3.

PubMed

Durig, James R; Pan, Chunhua; Guirgis, Gamil A

2003-03-15

The infrared (3100-40 cm(-1)) and Raman (3100-20 cm(-1)) spectra of gaseous and solid n-propylsilane, CH(3)CH(2)CH(2)SiH(3) and the Si-d(3) isotopomer, CH(3)CH(2)CH(2)SiD(3), have been recorded. Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values obtained. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 degrees C) studies of the infrared spectra of n-propylsilane dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 220+/-22 cm(-1) (2.63+/-0.26 kJ mol(-1)) with the anti conformer the more stable form. A similar value of 234+/-23 cm(-1) (2.80+/-0.28 kJ mol(-1)) was obtained for deltaH for the Si-d(3) isotopomer. At ambient temperature it is estimated that there is 30+/-2% of the gauche conformer present. The potential function governing the conformation interchange has been estimated from the far infrared spectral data, the enthalpy difference, and the dihedral angle of the gauche conformer, which is compared to the one predicted from ab initio MP2/6-31G(d) calculations. The barriers to conformational interchange are: 942, 970 and 716 cm(-1) for the anti to gauche, gauche to gauche, and gauche to anti conformers, respectively. Relatively complete vibrational assignments are proposed for both the n-propylsilane-d(0) and Si-d(3) molecules based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios, and normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities and depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311 + G(d,p) and 6-311 + G(2

Spectra and structure of silicon containing compounds. XXXII. Raman and infrared spectra, conformational stability, vibrational assignment and ab initio calculations of n-propylsilane-d 0 and Si-d 3

NASA Astrophysics Data System (ADS)

Durig, James R.; Pan, Chunhua; Guirgis, Gamil A.

2003-03-01

The infrared (3100-40 cm -1) and Raman (3100-20 cm -1) spectra of gaseous and solid n-propylsilane, CH 3CH 2CH 2SiH 3 and the Si-d 3 isotopomer, CH 3CH 2CH 2SiD 3, have been recorded. Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values obtained. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 °C) studies of the infrared spectra of n-propylsilane dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 220±22 cm -1 (2.63±0.26 kJ mol -1) with the anti conformer the more stable form. A similar value of 234±23 cm -1 (2.80±0.28 kJ mol -1) was obtained for Δ H for the Si-d 3 isotopomer. At ambient temperature it is estimated that there is 30±2% of the gauche conformer present. The potential function governing the conformation interchange has been estimated from the far infrared spectral data, the enthalpy difference, and the dihedral angle of the gauche conformer, which is compared to the one predicted from ab initio MP2/6-31G(d) calculations. The barriers to conformational interchange are: 942, 970 and 716 cm -1 for the anti to gauche, gauche to gauche, and gauche to anti conformers, respectively. Relatively complete vibrational assignments are proposed for both the n-propylsilane-d 0 and Si-d 3 molecules based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios, and normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities and depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311+G(d,p) and 6-311+G(2d,2p) basis sets. From the isolated

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE position the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad, for further processing. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE position the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad, for further processing. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

Water vapor in Titan's stratosphere from Cassini/CIRS Far-infrared spectra

NASA Astrophysics Data System (ADS)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bézard, B.; de Kok, R.; Lellouch, E.; Irwin, P. G. J.; Flasar, F. M.; Bampasidis, G.

2012-09-01

We report here the detection of stratospheric water vapor [1] using the Cassini Composite Infrared Spectrometer (CIRS, [2]). CIRS senses water emissions in the far infrared spectral region near 50 microns, which we have modeled using a radiative transfer computation code (NEMESIS, [3]). From the analysis of nadir spectra we have derived a mixing ratio of 0.14 ± 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 ± 1.3 × 1014 molecules/cm2. Using limb observations, we obtained mixing ratios of 0.13 ± 0.04 ppb at an altitude of 115 km and 0.45 ± 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models (e.g. [4], [5] and [6]); retrieved scaling factors (from ~ 0.1 to ~ 0.6) to the water profile suggested by these models show that water vapor is present in Titan's stratosphere with less abundance than predicted.

Path integral Liouville dynamics: Applications to infrared spectra of OH, water, ammonia, and methane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jian, E-mail: jianliupku@pku.edu.cn; State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871; Zhang, Zhijun

Path integral Liouville dynamics (PILD) is applied to vibrational dynamics of several simple but representative realistic molecular systems (OH, water, ammonia, and methane). The dipole-derivative autocorrelation function is employed to obtain the infrared spectrum as a function of temperature and isotopic substitution. Comparison to the exact vibrational frequency shows that PILD produces a reasonably accurate peak position with a relatively small full width at half maximum. PILD offers a potentially useful trajectory-based quantum dynamics approach to compute vibrational spectra of molecular systems.

Experimental studies of the far-infrared spectra of cosmic-type ices

NASA Technical Reports Server (NTRS)

Hudson, Reggie L.

1992-01-01

Work performed during the period is reported. The abstract of a paper presented at the Second International Workshop on the Nature of Cometary Organic Matter is included. Far infrared spectra of amorphous and crystalline water ice before and after proton irradiation is presented. Also, a study of clathrate hydrates was conducted in which a methanol (CH3OH) clathrate hydrate was prepared and its far-infrared spectrum investigated. This paper is also included.

The anharmonic quartic force field infrared spectra of hydrogenated and methylated PAHs.

PubMed

Mackie, Cameron J; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Buma, Wybren Jan; Lee, Timothy J; Tielens, Alexander G G M

2018-01-03

Polycyclic aromatic hydrocarbons (PAHs) have been shown to be ubiquitous in a large variety of distinct astrophysical environments and are therefore of great interest to astronomers. The majority of these findings are based on theoretically predicted spectra, which make use of scaled DFT harmonic frequencies for band positions and the double harmonic approximation for intensities. However, these approximations have been shown to fail at predicting high-resolution gas-phase infrared spectra accurately, especially in the CH-stretching region (2950-3150 cm -1 , 3 μm). This is particularly worrying for the subset of hydrogenated or methylated PAHs to which astronomers attribute the observed non-aromatic features that appear in the CH-stretching region of spectral observations of the interstellar medium (ISM). In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs and five non-linear PAHs, demonstrating the importance of including anharmonicities into theoretical calculations. In this work we extend these techniques to two methylated PAHs (9-methylanthracene, and 9,10-dimethylanthracene) and four hydrogenated PAHs (9,10-dihydroanthracene, 9,10-dihydrophenanthrene, 1,2,3,4-tetrahydronaphthalene, and 1,2,3,6,7,8-hexahydropyrene) in order to better understand the aliphatic IR features of substituted PAHs. The theoretical spectra are compared with the spectra obtained under matrix isolation low-temperature conditions for the full vibrational fundamental range and under high-resolution, low-temperature gas-phase conditions for the CH-stretching region. Excellent agreement is observed between the theoretical and high-resolution experimental spectra with a deviation of 0.00% ± 0.17%, and changes to the spectra of PAHs upon methylation and hydrogenated are tracked accurately and explained.

On the Widths of Bands in the Infrared Spectra of Oxyanions.

PubMed

Griffiths, Peter R; Eastman Fries, Brandy; Weakley, Andrew T

2018-01-01

It is well known that the antisymmetric stretching (ν 3 ) band in the mid-infrared spectra of oxyanion salts is usually very broad, whereas all the other fundamental bands are narrow. In this paper, we propose that the underlying cause of the increased width is the effect of the very high absorption index of this band for samples prepared with a range of particle sizes. When oxyanion salts are ground, the diameter of the resulting particles usually varies from less than 100 nm to about 2 µm. While the peak absorbance of the ν 3 band of the smaller particles (diameter < 200 nm) is less than 1, that of the larger particles can be as high as 6. We show that the average transmittance of these particles leads to a significant band broadening, especially when there are small voids in the resulting sample. Although the effect is always seen in the spectra of alkali halide disks and mineral oil mulls, it is also seen in diffuse reflection and attenuated total reflection (ATR) spectra. Because the depth of penetration of infrared radiation below 1500 cm -1 is less than 1 µm for ATR spectra measured with a germanium internal reflection element (IRE), the width of the ν 3 band is lower than that of ATR spectra measured with an IRE of lower refractive index such as diamond on zinc selenide.

Multivariate curve resolution using a combination of mid-infrared and near-infrared spectra for the analysis of isothermal epoxy curing reaction

NASA Astrophysics Data System (ADS)

Yamasaki, Hideki; Morita, Shigeaki

2018-05-01

Multivariate curve resolution (MCR) was applied to a hetero-spectrally combined dataset consisting of mid-infrared (MIR) and near-infrared (NIR) spectra collected during the isothermal curing reaction of an epoxy resin. An epoxy monomer, bisphenol A diglycidyl ether (BADGE), and a hardening agent, 4,4‧-diaminodiphenyl methane (DDM), were used for the reaction. The fundamental modes of the Nsbnd H and Osbnd H stretches were highly overlapped in the MIR region, while their first overtones could be independently identified in the NIR region. The concentration profiles obtained by MCR using the hetero-spectral combination showed good agreement with the results of calculations based on the Beer-Lambert law and the mass balance. The band assignments and absorption sites estimated by the analysis also showed good agreement with the results using two-dimensional (2D) hetero-correlation spectroscopy.

Empirical Measurement and Model Validation of Infrared Spectra of Contaminated Surfaces

NASA Astrophysics Data System (ADS)

Archer, Sean

The goal of this thesis was to validate predicted infrared spectra of liquid contaminated surfaces from a micro-scale bi-directional reflectance distribution function (BRDF) model through the use of empirical measurement. Liquid contaminated surfaces generally require more sophisticated radiometric modeling to numerically describe surface properties. The Digital Image and Remote Sensing Image Generation (DIRSIG) model utilizes radiative transfer modeling to generate synthetic imagery for a variety of applications. Aside from DIRSIG, a micro-scale model known as microDIRSIG has been developed as a rigorous ray tracing physics-based model that could predict the BRDF of geometric surfaces that are defined as micron to millimeter resolution facets. The model offers an extension from the conventional BRDF models by allowing contaminants to be added as geometric objects to a micro-facet surface. This model was validated through the use of Fourier transform infrared spectrometer measurements. A total of 18 different substrate and contaminant combinations were measured and compared against modeled outputs. The substrates used in this experiment were wood and aluminum that contained three different paint finishes. The paint finishes included no paint, Krylon ultra-flat black, and Krylon glossy black. A silicon based oil (SF96) was measured out and applied to each surface to create three different contamination cases for each surface. Radiance in the longwave infrared region of the electromagnetic spectrum was measured by a Design and Prototypes (D&P) Fourier transform infrared spectrometer and a Physical Sciences Inc. Adaptive Infrared Imaging Spectroradiometer (AIRIS). The model outputs were compared against the measurements quantitatively in both the emissivity and radiance domains. A temperature emissivity separation (TES) algorithm had to be applied to the measured radiance spectra for comparison with the microDIRSIG predicted emissivity spectra. The model predicted

Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Najarro, F.; Geballe, T. R.; Figer, D. F.

We report the detection of a number of emission lines in the 1.0–2.4 μ m spectra of four of the five bright-infrared dust-embedded stars at the center of the Galactic center’s (GC) Quintuplet Cluster. Spectroscopy of the central stars of these objects is hampered not only by the large interstellar extinction that obscures all of the objects in the GC, but also by the large amounts of warm circumstellar dust surrounding each of the five stars. The pinwheel morphologies of the dust observed previously around two of them are indicative of Wolf–Rayet colliding wind binaries; however, infrared spectra of eachmore » of the five have until now revealed only dust continua steeply rising to long wavelengths and absorption lines and bands from interstellar gas and dust. The emission lines detected, from ionized carbon and from helium, are broad and confirm that the objects are dusty late-type carbon Wolf–Rayet stars.« less

First-principles study of the infrared spectra of the ice Ih (0001) surface

DOE PAGES

Pham, T. Anh; Huang, P.; Schwegler, E.; ...

2012-08-22

Here, we present a study of the infrared (IR) spectra of the (0001) deuterated ice surface based on first-principles molecular dynamics simulations. The computed spectra show a good agreement with available experimental IR measurements. We identified the bonding configurations associated with specific features in the spectra, allowing us to provide a detailed interpretation of IR signals. We computed the spectra of several proton ordered and disordered models of the (0001) surface of ice, and we found that IR spectra do not appear to be a sensitive probe of the microscopic arrangement of protons at ice surfaces.

Infrared spectra alteration in water proximate to the palms of therapeutic practitioners.

PubMed

Schwartz, Stephan A; De Mattei, Randall J; Brame, Edward G; Spottiswoode, S James P

2015-01-01

Through standard techniques of infrared (IR) spectrophotometry, sterile water samples in randomly selected sealed vials evidence alteration of infrared (IR) spectra after being proximate to the palms of the hands of both Practicing and Non-practicing Therapy Practitioners, each of whom employed a personal variation of the Laying-on-of-Hands/Therapeutic Touch processes. This pilot study presents 14 cases, involving 14 Practitioners and 14 Recipients. The first hypothesis, that a variation in the spectra of all (84) Treated spectra compared with all (57) Control spectra would be observed in the 2.5-3.0µm range, was confirmed (P = .02). Overall, 10% (15) of the spectra were done using a germanium internal reflection element (IRE), and 90% of the spectra (126) were done with a zinc selenide IRE. The difference in refractive index between the two IREs skews the data. The zinc selenide IRE spectra alone yield P = .005. The authors believe the most representative evidence for the effect appeared in the sample group of Treated vs Calibration Controls using the zinc selenide IRE (P = .0004). The second hypothesis, that there existed a direct relationship between intensity of effect and time of exposure, was not confirmed. This study replicates earlier findings under conditions of blindness, randomicity, and several levels of controls. Environmental factors are considered as explanations for the observed IR spectrum alteration, including temperature, barometric pressure, and variations dependent on sampling order. They do not appear to explain the effect. Copyright © 2015. Published by Elsevier Inc.

Infrared spectra and density functional calculations for SMO2 molecules (M = Cr, Mo, W).

PubMed

Wang, Xuefeng; Andrews, Lester

2009-08-06

Infrared absorptions of the matrix isolated SMO2 (M = Cr, Mo, W) molecules were observed following laser-ablated metal atom reactions with SO2 during condensation in solid argon and neon. The symmetric and antisymmetric M-O stretching mode assignments were confirmed by appropriate S18O2 and S(16,18)O2 isotopic shifts. The much weaker Cr-S stretching mode was identified through its 34S shift. Density functional (B3LYP and BPW91) calculations were performed to obtain molecular structures and to reproduce the infrared spectra. Computed pyramidal structures for the SMO2 molecules are very similar to those for the analogous trioxides and this functional group in [MO2S(bdt)]2- complexes. Additional weaker absorptions are assigned to the (SO2)(SMO2) adducts, which are stabilized by a four-membered ring.

Investigating the Near-Infrared Properties of Planetary Nebulae II. Medium Resolution Spectra. 2; Medium Resolution Spectra

NASA Technical Reports Server (NTRS)

Hora, Joseph L.; Latter, William B.; Deutsch, Lynne K.

1998-01-01

We present medium-resolution (R approximately 700) near-infrared (lambda = 1 - 2.5 micrometers) spectra of a sample of planetary nebulae (PNe). A narrow slit was used which sampled discrete locations within the nebulae; observations were obtained at one or more positions in the 41 objects included in the survey. The PN spectra fall into one of four general categories: H1 emission line-dominated PNe, H1 and H2 emission line PNe, H2 emission line-dominated PNe, and continuum-dominated PNe. These categories correlate with morphological type, with the elliptical PNe falling into the first group, and the bipolar PNe primarily in the H2 and continuum emission groups. The categories also correlate with C/O ratio, with the O-rich objects falling into the first group and the C-rich objects in the groups. Other spectral features were observed in all catagories, such as continuum emission from the central star, and warm dust continuum emission towards the long wavelength end of the spectra. H2 was detected in four PNe in this survey for the first time. An analysis was performed using the H2 line ratios in all of the PN spectra in the survey where a sufficient number of lines were observed to determine the ortho-to-para ratio and the rotational and vibrational excitation temperatures of the H-2 in those objects. One unexpected result from this analysis is that the H-2 is excited by absorption of ultraviolet photons in most of the PNe, although there are several PNe in which collisional excitation plays an important role. The correlation between bipolar morphology and H2 emission has been strengthened with the new detections of H2 in this survey.

Infrared reflectance spectra: Effects of particle size, provenance and preparation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.

2014-09-22

We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectancemore » spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.« less

Infrared reflectance spectra: effects of particle size, provenance and preparation

NASA Astrophysics Data System (ADS)

Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.; Blake, Thomas A.; Forland, Brenda M.; Szecsody, J. E.; Johnson, Timothy J.

2014-10-01

We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectance spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 - 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.

Effect of pyridine on infrared absorption spectra of copper phthalocyanine.

PubMed

Singh, Sukhwinder; Tripathi, S K; Saini, G S S

2008-02-01

Infrared absorption spectra of copper phthalocyanine in KBr pellet and pyridine solution in 400-1625 and 2900-3200 cm(-1)regions are reported. In the IR spectra of solid sample, presence of weak bands, which are forbidden according to the selection rules of D4h point group, is explained on the basis of distortion in the copper phthalocyanine molecule caused by the crystal packing effects. Observation of a new band at 1511 cm(-1) and change in intensity of some other bands in pyridine are interpreted on the basis of coordination of the solvent molecule with the central copper ion.

Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

NASA Technical Reports Server (NTRS)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.;

Quantitative determination of band distortions in diamond attenuated total reflectance infrared spectra.

PubMed

Boulet-Audet, Maxime; Buffeteau, Thierry; Boudreault, Simon; Daugey, Nicolas; Pézolet, Michel

2010-06-24

Due to its unmatched hardness and chemical inertia, diamond offers many advantages over other materials for extreme conditions and routine analysis by attenuated total reflection (ATR) infrared spectroscopy. Its low refractive index can offer up to a 6-fold absorbance increase compared to germanium. Unfortunately, it also results for strong bands in spectral distortions compared to transmission experiments. The aim of this paper is to present a methodological approach to determine quantitatively the degree of the spectral distortions in ATR spectra. This approach requires the determination of the optical constants (refractive index and extinction coefficient) of the investigated sample. As a typical example, the optical constants of the fibroin protein of the silk worm Bombyx mori have been determined from the polarized ATR spectra obtained using both diamond and germanium internal reflection elements. The positions found for the amide I band by germanium and diamond ATR are respectively 6 and 17 cm(-1) lower than the true value dtermined from the k(nu) spectrum, which is calculated to be 1659 cm(-1). To determine quantitatively the effect of relevant parameters such as the film thickness and the protein concentration, various spectral simulations have also been performed. The use of a thinner film probed by light polarized in the plane of incidence and diluting the protein sample can help in obtaining ATR spectra that are closer to their transmittance counterparts. To extend this study to any system, the ATR distortion amplitude has been evaluated using spectral simulations performed for bands of various intensities and widths. From these simulations, a simple empirical relationship has been found to estimate the band shift from the experimental band height and width that could be of practical use for ATR users. This paper shows that the determination of optical constants provides an efficient way to recover the true spectrum shape and band frequencies of

Multivariate curve resolution using a combination of mid-infrared and near-infrared spectra for the analysis of isothermal epoxy curing reaction.

PubMed

Yamasaki, Hideki; Morita, Shigeaki

2018-05-15

Multivariate curve resolution (MCR) was applied to a hetero-spectrally combined dataset consisting of mid-infrared (MIR) and near-infrared (NIR) spectra collected during the isothermal curing reaction of an epoxy resin. An epoxy monomer, bisphenol A diglycidyl ether (BADGE), and a hardening agent, 4,4'-diaminodiphenyl methane (DDM), were used for the reaction. The fundamental modes of the NH and OH stretches were highly overlapped in the MIR region, while their first overtones could be independently identified in the NIR region. The concentration profiles obtained by MCR using the hetero-spectral combination showed good agreement with the results of calculations based on the Beer-Lambert law and the mass balance. The band assignments and absorption sites estimated by the analysis also showed good agreement with the results using two-dimensional (2D) hetero-correlation spectroscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of the Characteristics and Classification of Near-Infrared Spectra of Patchouli Oil (Pogostemon Cablin Benth.) from Different Origin

NASA Astrophysics Data System (ADS)

Diego, M. C. R.; Purwanto, Y. A.; Sutrisno; Budiastra, I. W.

2018-05-01

Research related to the non-destructive method of near-infrared (NIR) spectroscopy in aromatic oil is still in development in Indonesia. The objectives of the study were to determine the characteristics of the near-infrared spectra of patchouli oil and classify it based on its origin. The samples were selected from seven different places in Indonesia (Bogor and Garut from West Java, Aceh, and Jambi from Sumatra and Konawe, Masamba and Kolaka from Sulawesi Island). The spectral data of patchouli oil was obtained by FT-NIR spectrometer at the wavelength of 1000-2500 nm, and after that, the samples were subjected to composition analysis using Gas Chromatography-Mass Spectrometry. The transmittance and absorbance spectra were analyzed and then principal component analysis (PCA) was carried out. Discriminant analysis (DA) of the principal component was developed to classify patchouli oil based on its origin. The result shows that the data of both spectra (transmittance and absorbance spectra) by the PC analysis give a similar result for discriminating the seven types of patchouli oil due to their distribution and behavior. The DA of the three principal component in both data processed spectra could classify patchouli oil accurately. This result exposed that NIR spectroscopy can be successfully used as a correct method to classify patchouli oil based on its origin.

Near-Infrared Spectra of Type Ia Supernovae

NASA Technical Reports Server (NTRS)

Marion, G. H.; Hoeflich, P.; Vacca, W. D.; Wheeler, J. C.

2003-01-01

We report near-infrared (NIR) spectroscopic observations of 12 'branch-normal' Type Ia supernovae (SNe Ia) that cover the wavelength region from 0.8 to 2.5 microns. Our sample more than doubles the number of SNe Ia with published NIR spectra within 3 weeks of maximum light. The epochs of observation range from 13 days before maximum light to 18 days after maximum light. A detailed model for a Type Ia supernovae is used to identify spectral features. The Doppler shifts of lines are measured to obtain the velocity and thus the radial distribution of elements. The NIR is an extremely useful tool to probe the chemical structure in the layers of SNe Ia ejecta. This wavelength region is optimal for examining certain products of the SNe Ia explosion that may be blended or obscured in other spectral regions. We identify spectral features from Mg II, Ca II, Si II, Fe II, Co II, Ni II, and possibly Mn II. We find no indications for hydrogen, helium, or carbon in the spectra. The spectral features reveal important clues about the physical characteristics of SNe Ia. We use the features to derive upper limits for the amount of unburned matter, to identify the transition regions from explosive carbon to oxygen burning and from partial to complete silicon burning, and to estimate the level of mixing during and after the explosion. Elements synthesized in the outer layers during the explosion appear to remain in distinct layers. That provides strong evidence for the presence of a detonation phase during the explosion as it occurs in delayed detonation or merger models. Mg II velocities are found to exceed 11,000 - 15,000 km/s, depending on the individual SNe Ia. That result suggests that burning during the explosion reaches the outermost layers of the progenitor and limits the amount of unburned material to less than 10% of the mass of the progenitor. Small residuals of unburned material are predicted by delayed detonation models but are inconsistent with pure deflagration or

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE check the placement of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad for further processing. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE check the placement of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad for further processing. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE begin the next phase of processing of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE begin the next phase of processing of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE erect a ladder to reach the top of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE erect a ladder to reach the top of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove a portion of a transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove a portion of a transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove sections of the transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove sections of the transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE prepare to remove the canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE prepare to remove the canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - In the NASA Spacecraft Hangar AE, the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad, is uncovered by workers following its arrival. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - In the NASA Spacecraft Hangar AE, the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad, is uncovered by workers following its arrival. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE lift the protective cover from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE lift the protective cover from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove the protective cover from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE remove the protective cover from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

Short communication: Development of an equation for estimating methane emissions of dairy cows from milk Fourier transform mid-infrared spectra by using reference data obtained exclusively from respiration chambers.

PubMed

Vanlierde, A; Soyeurt, H; Gengler, N; Colinet, F G; Froidmont, E; Kreuzer, M; Grandl, F; Bell, M; Lund, P; Olijhoek, D W; Eugène, M; Martin, C; Kuhla, B; Dehareng, F

2018-05-09

Evaluation and mitigation of enteric methane (CH 4 ) emissions from ruminant livestock, in particular from dairy cows, have acquired global importance for sustainable, climate-smart cattle production. Based on CH 4 reference measurements obtained with the SF 6 tracer technique to determine ruminal CH 4 production, a current equation permits evaluation of individual daily CH 4 emissions of dairy cows based on milk Fourier transform mid-infrared (FT-MIR) spectra. However, the respiration chamber (RC) technique is considered to be more accurate than SF 6 to measure CH 4 production from cattle. This study aimed to develop an equation that allows estimating CH 4 emissions of lactating cows recorded in an RC from corresponding milk FT-MIR spectra and to challenge its robustness and relevance through validation processes and its application on a milk spectral database. This would permit confirming the conclusions drawn with the existing equation based on SF 6 reference measurements regarding the potential to estimate daily CH 4 emissions of dairy cows from milk FT-MIR spectra. A total of 584 RC reference CH 4 measurements (mean ± standard deviation of 400 ± 72 g of CH 4 /d) and corresponding standardized milk mid-infrared spectra were obtained from 148 individual lactating cows between 7 and 321 d in milk in 5 European countries (Germany, Switzerland, Denmark, France, and Northern Ireland). The developed equation based on RC measurements showed calibration and cross-validation coefficients of determination of 0.65 and 0.57, respectively, which is lower than those obtained earlier by the equation based on 532 SF 6 measurements (0.74 and 0.70, respectively). This means that the RC-based model is unable to explain the variability observed in the corresponding reference data as well as the SF 6 -based model. The standard errors of calibration and cross-validation were lower for the RC model (43 and 47 g/d vs. 66 and 70 g/d for the SF 6 version, respectively), indicating

Visible/near-infrared spectra and two-layer modeling of palagonite-coated Basalts

USGS Publications Warehouse

Johnson, J. R.; Grundy, W.M.

2001-01-01

Fine-grained dust coatings on Martian rocks and soils obscure underlying surfaces and hinder mineralogic interpretations of both remote sensing and in-situ observations. We investigate laboratory visible/near-infrared spectra of various thicknesses of palagonite coatings on basalt substrates. We develop a two-layer Hapke scattering model incorporating porosity, grain size, and derived absorption coefficients of palagonite and basalt that reproduces the observed spectra only when the single scattering particle phase function is varied with wavelength.

Fast forward modeling of Titan's infrared spectra to invert VIMS/Cassini hyperspectral images

USGS Publications Warehouse

Rodriguez, S.; Le Mouélic, Stéphane; Rannou, P.; Combe, J.-P.; Corre, L.L.; Tobie, G.; Barnes, J.W.; Sotin, Christophe; Brown, R.H.; Baines, K.H.; Buratti, B.J.; Clark, R.N.; Nicholson, P.D.

2009-01-01

The surface of Titan, the largest icy moon of Saturn, is veiled by a very thick and hazy atmosphere. The Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft, in orbit around Saturn since July 2004, conduct an intensive survey of Titan with the objective to understand the complex nature of the atmosphere and surface of the mysterious moon and the way they interact. Accurate radiative transfer modeling is necessary to analyze Titan's infrared spectra, but are often very computer resources demanding. As Cassini has gathered hitherto millions of spectra of Titan and will still observe it until at least 2010, we report here on the development of a new rapid, simple and versatile radiative transfer model specially designed to invert VIMS datacubes. ?? 2009 IEEE.

A new method to obtain Fourier transform infrared spectra free from water vapor disturbance.

PubMed

Chen, Yujing; Wang, Hai-Shui; Umemura, Junzo

2010-10-01

Infrared absorption bands due to water vapor in the mid-infrared regions often obscure important spectral features of the sample. Here, we provide a novel method to collect a qualified infrared spectrum without any water vapor interference. The scanning procedure for a single-beam spectrum of the sample is divided into two stages under an atmosphere with fluctuating humidity. In the first stage, the sample spectrum is measured with approximately the same number of scans as the background. If the absorbance of water vapor in the spectrum is positive (or negative) at the end of the first stage, then the relative humidity in the sample compartment of the spectrometer is changed by a dry (or wet) air blow at the start of the second stage while the measurement of the sample spectrum continues. After the relative humidity changes to a lower (or higher) level than that of the previously collected background spectrum, water vapor peaks will become smaller and smaller with the increase in scanning number during the second stage. When the interfering water lines disappear from the spectrum, the acquisition of a sample spectrum is terminated. In this way, water vapor interference can finally be removed completely.

Water Vapor on Titan: The Stratospheric Vertical Profile from Cassini/CIRS Infrared Spectra

NASA Technical Reports Server (NTRS)

Cottini, V.; Jennings, D. E.; Nixon, C. A.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Achterberg, R. K.; Teanby, N. A.; deKok, R.;

The 4 micron spectra of compact infrared sources

NASA Technical Reports Server (NTRS)

Hofmann, R.; Larson, H. P.; Fink, U.

1986-01-01

High resolution 5 arcsec spectra in the 4 micron region are presented of the central 5 arcsec of the compact near infrared sources K3-50, W51-IRS2 East, and G333.6-0.2. From measured Br-alpha/Pf-beta line ratios and previously published infrared and radio maps, it is concluded that standard recombination theory fails to explain our observations in at least two cases. It is demonstrated that the data are consistent with thermal excitation of the hydrogen lines in strong stellar winds. The Pf-beta Hu-epsilon line ratio, which is completely insensitive to differential extinction, confirms the need for the stellar wind model for the core of G333.6-0.2. From the (K III) line it is estimated that the potassium abundance in G333.6-0.2 is at least equal to the solar value, and possibly enhanced by a factor up to 10.

Compositional stratigraphy of crustal material from near-infrared spectra

NASA Technical Reports Server (NTRS)

Pieters, Carle M.

1987-01-01

An Earth-based telescopic program to acquire near-infrared spectra of freshly exposed lunar material now contains data for 17 large impact craters with central peaks. Noritic, gabbroic, anorthositic and troctolitic rock types can be distinguished for areas within these large craters from characteristic absorptions in individual spectra of their walls and central peaks. Norites dominate the upper lunar crust while the deeper crustal zones also contain significant amounts of gabbros and anorthosites. Data for material associated with large craters indicate that not only is the lunar crust highly heterogeneous across the nearside, but that the compositional stratigraphy of the lunar crust is nonuniform. Crustal complexity should be expected for other planetary bodies, which should be studied using high spatial and spectral resolution data in and around large impact craters.

Effects of sample preparation on the infrared reflectance spectra of powders

NASA Astrophysics Data System (ADS)

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

2015-05-01

While reflectance spectroscopy is a useful tool for identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-loaded as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample can have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

Infrared Analysis Using Tissue Paper.

ERIC Educational Resources Information Center

Owen, Noel L.; Wood, Steven G.

1987-01-01

Described is a quick, easy, and cheap, but effective method of obtaining infrared spectra of solids and nonvolatile liquids by Fourier transform infrared spectroscopy. The technique uses tissue paper as a support matrix. (RH)

Infrared reflectance spectra (2. 2-15. mu. m) of plagioclase feldspars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nash, D.B.; Salisbury, J.W.

Laboratory results show that (1) the Christiansen frequency (CF) feature in mid-infrared reflectance spectra of powders can be used to accurately distinguish plagioclase composition, and (2) the wavelength position of the CF is not affected by vitrification of the plagioclase. Although the CF position does not distinguish glass from crystalline forms of plagioclase, other features (combination-tone, overtone, restrahlen bands) in the mid-IR spectra of plagioclase can be used for that purpose. These results have important implications for application of thermal emission spectroscopy to mapping the surface composition of regolith-covered planetary bodies like the Moon, Mars, and asteroids.

Microwave, infrared and Raman spectra, conformational stability and vibrational assignment of methoxyflurane

NASA Astrophysics Data System (ADS)

Li, Y. S.; Durig, J. R.

1982-05-01

The low resolution microwave spectrum of methoxyflurane, CHCl 2CF 2OCH 3, has been recorded from 26.5 to 39.0 GHz. From the spacing of the major transitions it is shown that the value of 2036 MHz for B + C is consistent with the trans-trans or gauche-trans conformers where the first term ( trans or gauche) refers to the internal rotation around the C-C bond. The infrared (40-3500 cm -1) and the Raman (20-3500 cm -1) spectra have been recorded for gaseous and solid methoxyflurane. Additionally, the Raman spectrum of the liquid has been obtained and qualitative depolarization ratios measured. From these data it is shown that the most stable form in the fluid phases at ambient temperature is the gauche-trans conformer but the trans-trans form is the most stable in the solid state. A complete vibrational analysis based on infrared band contours, depolarization values and group frequencies is proposed for this conformer. From the analysis of the low frequency vibrational data, values of some of the barriers to internal rotation are estimated. These results are compared to some similar quantities for some corresponding molecules.

Infrared spectra of some sulfides and their analogs of binary composition in the long-wave region

NASA Technical Reports Server (NTRS)

Povarennykh, A. S.; Sidorenko, G. A.; Solntseva, L. S.; Solntsev, B. P.

1981-01-01

The far infrared spectra (500-60/cm) of some simple sulfides and their analogs were studied. In all, 22 minerals with different structure types were investigated, out of which 14 are sulfides (galena, alabandite, pyrrhotite, sphalerite, wurtzite, cinnabar, realgar, orpiment, getchelite antimonite, molybdenite, pyrite, marcasite and heazlewoodite) 6 arsenides (niccolite, domeykite, arsenopyrite, lollingite, rammelsbergite and skutterudite), one telluride (tetradymite) and native arsenic. The main bands of infrared absorption spectra of the minerals are compared with the relative strength of the interatomic bonds and their interpretation is given.

Water Vapor in Titan's Stratosphere from Cassini/CIRS Far-infrared Spectra

NASA Technical Reports Server (NTRS)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.;

Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.

2015-05-22

While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packedmore » as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.« less

Baseline Correction of Diffuse Reflection Near-Infrared Spectra Using Searching Region Standard Normal Variate (SRSNV).

PubMed

Genkawa, Takuma; Shinzawa, Hideyuki; Kato, Hideaki; Ishikawa, Daitaro; Murayama, Kodai; Komiyama, Makoto; Ozaki, Yukihiro

2015-12-01

An alternative baseline correction method for diffuse reflection near-infrared (NIR) spectra, searching region standard normal variate (SRSNV), was proposed. Standard normal variate (SNV) is an effective pretreatment method for baseline correction of diffuse reflection NIR spectra of powder and granular samples; however, its baseline correction performance depends on the NIR region used for SNV calculation. To search for an optimal NIR region for baseline correction using SNV, SRSNV employs moving window partial least squares regression (MWPLSR), and an optimal NIR region is identified based on the root mean square error (RMSE) of cross-validation of the partial least squares regression (PLSR) models with the first latent variable (LV). The performance of SRSNV was evaluated using diffuse reflection NIR spectra of mixture samples consisting of wheat flour and granular glucose (0-100% glucose at 5% intervals). From the obtained NIR spectra of the mixture in the 10 000-4000 cm(-1) region at 4 cm intervals (1501 spectral channels), a series of spectral windows consisting of 80 spectral channels was constructed, and then SNV spectra were calculated for each spectral window. Using these SNV spectra, a series of PLSR models with the first LV for glucose concentration was built. A plot of RMSE versus the spectral window position obtained using the PLSR models revealed that the 8680–8364 cm(-1) region was optimal for baseline correction using SNV. In the SNV spectra calculated using the 8680–8364 cm(-1) region (SRSNV spectra), a remarkable relative intensity change between a band due to wheat flour at 8500 cm(-1) and that due to glucose at 8364 cm(-1) was observed owing to successful baseline correction using SNV. A PLSR model with the first LV based on the SRSNV spectra yielded a determination coefficient (R2) of 0.999 and an RMSE of 0.70%, while a PLSR model with three LVs based on SNV spectra calculated in the full spectral region gave an R2 of 0.995 and an RMSE of

Infrared and Raman Spectra of Magnesium Ammonium Phosphate Hexahydrate (Struvite) and its Isomorphous Analogues. VIII. Spectra of Protiated and Partially Deuterated Magnesium Rubidium Phosphate Hexahydrate and Magnesium Thallium Phosphate Hexahydrate.

PubMed

Soptrajanov, Bojan; Cahil, Adnan; Najdoski, Metodija; Koleva, Violeta; Stefov, Viktor

2011-09-01

The infrared and Raman spectra of magnesium rubidium phosphate hexahydrate MgRbPO4 • 6H2O and magnesium thallium phosphate hexahydrate, MgTlPO4 • 6H2O were recorded at room temperature (RT) and the boiling temperature of liquid nitrogen (LNT). To facilitate their analysis, also recorded were the spectra of partially deuterated analogues with varying content of deuterium. The effects of deuteration and those of lowering the temperature were the basis of the conclusions drawn regarding the origin of the observed bands which were assigned to vibrations which are predominantly localized in the water molecules (four crystallographically different types of such molecules exist in the structures) and those with PO43- character. It was concluded that in some cases coupling of phosphate and water vibrations is likely to take place. The appearance of the infrared spectra in the O-H stretching regions of the infrared spectra is explained as being the result of an extensive overlap of bands due to components of the fundamental stretching modes of the H2O units with a possible participation of bands due to second-order transitions. A broad band reminiscent of the B band of the well-known ABC trio characteristic of spectra of substances containing strong hydrogen bonds in their structure was found around 2400 cm-1 in the infrared spectra of the two studied compounds.

Acidic weathering of basalt and basaltic glass: 1. Near-infrared spectra, thermal infrared spectra, and implications for Mars

NASA Astrophysics Data System (ADS)

Horgan, Briony H. N.; Smith, Rebecca J.; Cloutis, Edward A.; Mann, Paul; Christensen, Philip R.

2017-01-01

Acid-leached rinds and coatings occur in volcanic environments on Earth and have been identified using orbital spectroscopy on Mars, but their development is poorly understood. We simulated long-term open-system acidic weathering in a laboratory by repeatedly rinsing and submerging crystalline and glassy basalts in pH 1 and pH 3 acidic solutions for 213 days and compared their visible/near-infrared (0.3-2.5 µm) and thermal infrared (5-50 µm) spectral characteristics to their microscopic physical and chemical properties from scanning electron microscopy (SEM). We find that while alteration at moderately low pH ( 3) can produce mineral precipitates from solution, it has very little spectral or physical effect on the underlying parent material. In contrast, alteration at very low pH ( 1) results in clear silica spectral signatures for all crystalline samples while glasses exhibit strong blue concave-up near-infrared slopes. SEM indicates that these spectral differences correspond to different modes of alteration. In glass, alteration occurs only at the surface and produces a silica-enriched leached rind, while in more crystalline samples, alteration penetrates the interior to cause dissolution and replacement by silica. We confirm that glass is more stable than crystalline basalt under long-term acidic leaching, suggesting that glass could be enriched and common in terrains on Mars that have been exposed to acidic weathering. Leached glasses are consistent with both OMEGA and Thermal Emission Spectrometer (TES) spectra of the Martian northern lowlands and may contribute to the high-silica phases detected globally in TES Surface Type 2. Thus, both glass-rich deposits and acidic weathering may have been widespread on Mars.

Optical filter selection for high confidence discrimination of strongly overlapping infrared chemical spectra.

PubMed

Major, Kevin J; Poutous, Menelaos K; Ewing, Kenneth J; Dunnill, Kevin F; Sanghera, Jasbinder S; Aggarwal, Ishwar D

2015-09-01

Optical filter-based chemical sensing techniques provide a new avenue to develop low-cost infrared sensors. These methods utilize multiple infrared optical filters to selectively measure different response functions for various chemicals, dependent on each chemical's infrared absorption. Rather than identifying distinct spectral features, which can then be used to determine the identity of a target chemical, optical filter-based approaches rely on measuring differences in the ensemble response between a given filter set and specific chemicals of interest. Therefore, the results of such methods are highly dependent on the original optical filter choice, which will dictate the selectivity, sensitivity, and stability of any filter-based sensing method. Recently, a method has been developed that utilizes unique detection vector operations defined by optical multifilter responses, to discriminate between volatile chemical vapors. This method, comparative-discrimination spectral detection (CDSD), is a technique which employs broadband optical filters to selectively discriminate between chemicals with highly overlapping infrared absorption spectra. CDSD has been shown to correctly distinguish between similar chemicals in the carbon-hydrogen stretch region of the infrared absorption spectra from 2800-3100 cm(-1). A key challenge to this approach is how to determine which optical filter sets should be utilized to achieve the greatest discrimination between target chemicals. Previous studies used empirical approaches to select the optical filter set; however this is insufficient to determine the optimum selectivity between strongly overlapping chemical spectra. Here we present a numerical approach to systematically study the effects of filter positioning and bandwidth on a number of three-chemical systems. We describe how both the filter properties, as well as the chemicals in each set, affect the CDSD results and subsequent discrimination. These results demonstrate the

THE NASA AMES POLYCYCLIC AROMATIC HYDROCARBON INFRARED SPECTROSCOPIC DATABASE: THE COMPUTED SPECTRA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauschlicher, C. W.; Ricca, A.; Boersma, C.

The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant to test and refine the PAH hypothesis have been assembled into a spectroscopic database. This database now contains over 800 PAH spectra spanning 2-2000 {mu}m (5000-5 cm{sup -1}). These data are now available on the World Wide Web at www.astrochem.org/pahdb. This paper presents an overview of the computational spectra in the database and the tools developed to analyzemore » and interpret astronomical spectra using the database. A description of the online and offline user tools available on the Web site is also presented.« less

Improved assignments of the vibrational fundamental modes of ortho -, meta -, and para -xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindenmaier, Rodica; Scharko, Nicole K.; Tonkyn, Russell G.

Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, we report high quality quantitative vapor-phase infrared spectra of all three isomers over the 540-6500 cm -1 range. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C 2v symmetry for ortho-xylene, andmore » two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have C s and C 2 symmetry, and for para-xylene these conformers have C 2v or C 2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, we made an arbitrary choice to discuss the C s conformer for meta-xylene and the C 2v conformer for para-xylene. We report integrated band intensities for all isomers. Using the quantitative infrared data, we determine the global warming potential values of each isomer and discuss potential bands for atmospheric monitoring.« less

Improved assignments of the vibrational fundamental modes of ortho-, meta-, and para-xylene using gas- and liquid-phase infrared and Raman spectra combined with ab initio calculations: Quantitative gas-phase infrared spectra for detection

NASA Astrophysics Data System (ADS)

Lindenmaier, Rodica; Scharko, Nicole K.; Tonkyn, Russell G.; Nguyen, Kiet T.; Williams, Stephen D.; Johnson, Timothy J.

2017-12-01

Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, high quality quantitative vapor-phase infrared spectra of all three isomers over the 6500 - 540 cm-1 range are reported. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have Cs and C2 symmetry, and for para-xylene these conformers have C2v or C2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, an arbitrary choice to discuss the Cs conformer for meta-xylene and the C2v conformer for para-xylene is made. Integrated band intensities for all isomers are reported. Using the quantitative infrared data, the global warming potential values of each isomer are determined. Potential bands for atmospheric monitoring are also discussed.

Correlation of quality measurements to visible-near infrared spectra of pasteurized egg

USDA-ARS?s Scientific Manuscript database

A twelve week study was conducted on the egg albumen from both pasteurized and non-pasteurized shell eggs using visible-near infrared spectroscopy. Correlation of the chemical changes detected in the spectra to the measurement of Haugh units (measure of interior egg quality) was carried out using ch...

Matrix isolation infrared and Raman spectra of binary and mixed group II B fluorides

NASA Astrophysics Data System (ADS)

Givan, A.; Loewenschuss, A.

1980-03-01

Infrared and Raman spectra of all MF2 and MFX molecules (M=Zn, Cd, Hg; X=Cl, Br) and the infrared spectrum of the fluoroidide HgFI isolated in solid krypton at 20 °K are reported. The MFX species were formed in a vapor mixture of the appropriate MF2 and MX2 dihalides, vaporized, at different temperatures, from separate compartments of a double-oven crucible. The spectra are the first experimental evidence for the existence of the molecular fluorohalides. All three fundamentals of the MF2 molecules and the two stretching mode frequencies of the MFX molecules are assigned. Harmonic force constants are evaluated and isotope effects are used to discuss their geometry. Thermodynamic functions are tabulated for the binary difluorides.

Conformational landscape, photochemistry, and infrared spectra of sulfanilamide.

PubMed

Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

2013-01-31

assignment of the infrared spectra of this crystalline variety as well as of those of the β-polymorph room temperature crystalline sample and low temperature amorphous state was undertaken with help of theoretical results obtained for the crystallographically relevant dimer of SA.

CH3Cl, CH2Cl2, CHCl3, and CCl4: Infrared spectra, radiative efficiencies, and global warming potentials

NASA Astrophysics Data System (ADS)

Wallington, Timothy J.; Pivesso, Bruno Pasquini; Lira, Alane Moura; Anderson, James E.; Nielsen, Claus Jørgen; Andersen, Niels Højmark; Hodnebrog, Øivind

2016-05-01

Infrared spectra for the title compounds were measured experimentally in 700 Torr of air at 295 K and systematically modeled in B3LYP, M06-2X and MP2 calculations employing various basis sets. Calibrated infrared spectra over the wavenumber range 600-3500 cm-1 are reported and combined with literature data to provide spectra for use in experimental studies and radiative transfer calculations. Integrated absorption cross sections are (units of cm-1 molecule-1): CH3Cl, 660-780 cm-1, (3.89±0.19)×10-18; CH2Cl2, 650-800 cm-1, (2.16±0.11)×10-17; CHCl3, 720-810 cm-1, (4.08±0.20)×10-17; and CCl4, 730-825 cm-1, (6.30±0.31)×10-17. CH3Cl, CH2Cl2, CHCl3, and CCl4 have radiative efficiencies of 0.004, 0.028, 0.070, and 0.174 W m-2 ppb-1 and global warming potentials (100 year horizon) of 5, 8, 15, and 1775, respectively. Quantum chemistry calculations generally predict larger band intensities than the experimental values. The best agreement with experiments is obtained in MP2(Full) calculations employing basis sets of at least triple-zeta quality augmented by diffuse functions. The B3LYP functional is found ill-suited for calculating vibrational frequencies and infrared intensities of halocarbons.

An original data treatment for infrared spectra of organic matter, application to extracted soil organic matter

NASA Astrophysics Data System (ADS)

Gomes Rossin, Bruna; Redon, Roland; Raynaud, Michel; Nascimento, Nadia Regina; Mounier, Stéphane

2017-04-01

Infrared spectra of extracted organic matter are easy and rapid to do, but generally hard to interpreted over the presence or not of certain organic functions. Indeed, the organic matter is a complex mixture of molecules often having absorption overlapping and it is also difficult to have a well calibrated or normalised spectra due to the difficulty to have a well known solid content or homogeneity for a sample (Monakhova et al. 2015, Tadini et al. 2015, Bardy et al. 2008). In this work, the IRTF (InfraRed Fourier Transform) spectra were treated by an original algorithm developed to obtain the principal components of the IRTF spectra and their contributions for each sample. This bilinear decomposition used a PCA initialisation and the principal components were estimated from vectors calculated by PCA and linearly combined to provide non-negative signals minimizing a criterion based on cross-correlation. Hence, using this decomposition, it is possible to define IRTF signal of organic matter fractions like humic acid or fulvic acid depending on their origin like surface of depth of soil profiles. The method was used on a set of sample from Upper Negro River Basin (Amazon, Brazil) (Bueno,2009), where three soils sequences from surface to two meter depth containing 10 slices each. The sequences were sampled on a podzol well drain, a hydromorphic podzol and a cryptopodzol. From the IRTF data five representative component spectra were defined for all the extracted organic matter , and using other chemical composition information, a mechanism of organic matter fate is proposed to explain the observed results. Bardy, M., E. Fritsch, S. Derenne, T. Allard, N. R. do Nascimento, and G. T. Bueno. 2008. "Micromorphology and Spectroscopic Characteristics of Organic Matter in Waterlogged Podzols of the Upper Amazon Basin." Geoderma 145 (3-4): 222-30. Bueno, G.T. Appauvrissement et podzolisation des latérites du baissin du Rio Negro et gênese dês Podzols dans le haut bassin

Modeling the Infrared Spectra of Earth-Analog Exoplanets

NASA Astrophysics Data System (ADS)

Nixon, C.

2014-04-01

As a preparation for future observations with the James Webb Space Telescope (JWST) and other facilities, we have undertaken to model the infrared spectra of Earth-like exoplanets. Two atmospheric models were used: the modern (low CO2) and archean (high CO2) predictive models of the Kasting group at Penn state. Several model parameters such as distance to star, and stellar type (visible-UV spectrum spectrum) were adjusted, and the models reconverged. Subsequently, the final model atmospheres were input to a radiative transfer code (NEMESIS) and the results intercompared to search for the most significant spectral changes. Implications for exoplanet spectrum detectivity will be discussed.

Visible and near-infrared (0.4-2.5 μm) reflectance spectra of playa evaporite minerals

USGS Publications Warehouse

Crowley, James K.

1991-01-01

Visible and near-infrared (VNIR; 0.4–2.4 μm) reflectance spectra were recorded for 35 saline minerals that represent the wide range of mineral and brine chemical compositions found in playa evaporite settings. The spectra show that many of the saline minerals exhibit diagnostic near-infrared absorption bands, chiefly attributable to vibrations of hydrogen-bonded structural water molecules. VNIR reflectance spectra can be used to detect minor hydrate phases present in mixtures dominated by anhydrous halite or thenardite, and therefore will be useful in combination with X ray diffraction data for characterizing natural saline mineral assemblages. In addition, VNIR reflectance spectra are sensitive to differences in sample hydration state and should facilitate in situ studies of minerals that occur as fragile, transitory dehydration products in natural salt crusts. The use of spectral reflectance measurements in playa studies should aid in mapping evaporite mineral distributions and may provide insight into the geochemical and hydrological controls on playa mineral and brine development.

Partitioning Ocean Wave Spectra Obtained from Radar Observations

NASA Astrophysics Data System (ADS)

Delaye, Lauriane; Vergely, Jean-Luc; Hauser, Daniele; Guitton, Gilles; Mouche, Alexis; Tison, Celine

2016-08-01

2D wave spectra of ocean waves can be partitioned into several wave components to better characterize the scene. We present here two methods of component detection: one based on watershed algorithm and the other based on a Bayesian approach. We tested both methods on a set of simulated SWIM data, the Ku-band real aperture radar embarked on the CFOSAT (China- France Oceanography Satellite) mission which launch is planned mid-2018. We present the results and the limits of both approaches and show that Bayesian method can also be applied to other kind of wave spectra observations as those obtained with the radar KuROS, an airborne radar wave spectrometer.

Medium-range structural properties of vitreous germania obtained through first-principles analysis of vibrational spectra.

PubMed

Giacomazzi, Luigi; Umari, P; Pasquarello, Alfredo

2005-08-12

We analyze the principal vibrational spectra of vitreous GeO(2) and derive therefrom structural properties referring to length scales beyond the basic tetrahedral unit. We generate a model structure that yields a neutron structure factor in accord with experiment. The inelastic-neutron, the infrared, and the Raman spectra, calculated within a density-functional approach, also agree with respective experimental spectra. The accord for the Raman spectrum supports a Ge-O-Ge angle distribution centered at 135 degrees. The Raman feature X(2) is found to result from vibrations in three-membered rings, and therefore constitutes a distinctive characteristic of the medium-range structure.

Infrared spectra of hexamethylbenzene—tetracyanoethylene complexes at high pressures

NASA Astrophysics Data System (ADS)

Yamada, Haruka; Saheki, Masao

Infrared spectra of hexamethylbenzene(HMB)—tetracyanoethylene(TCNE), 1:1 and 2:1, complexes were measured under high pressures, 11˜4,000 bar. It was found that the CC stretching (A g) band of TCNE became much stronger at high pressures than at 1 bar and that the intensity increase of this band was especially large for both of the complexes. Based on these facts the strong appearance of the CC band at 1 bar, which is inconsistent with the symmetry consideration derived from X-ray analysis, can be discussed.

Transmission Spectra of HgTe-Based Quantum Wells and Films in the Far-Infrared Range

NASA Astrophysics Data System (ADS)

Savchenko, M. L.; Vasil'ev, N. N.; Yaroshevich, A. S.; Kozlov, D. A.; Kvon, Z. D.; Mikhailov, N. N.; Dvoretskii, S. A.

2018-04-01

Strained 80-nm-thick HgTe films belong to a new class of materials referred to as three-dimensional topological insulators (i.e., they have a bulk band gap and spin-nondegenerate surface states). Though there are a number of studies devoted to analysis of the properties of surface states using both transport and magnetooptical techniques in the THz range, the information about direct optical transitions between bulk and surface bands in these systems has not been reported. This study is devoted to the analysis of transmission and reflection spectra of HgTe films of different thicknesses in the far-infrared range recorded in a wide temperature range in order to detect the above interband transitions. A peculiarity at 15 meV, which is sensitive to a change in the temperature, is observed in spectra of both types. Detailed analysis of the data obtained revealed that this feature is related to absorption by HgTe optical phonons, while the interband optical transitions are suppressed.

Foreign molecules and ions in beryl obtained by infrared and visible spectroscopy

NASA Astrophysics Data System (ADS)

Jelić, Ivana; Logar, Mihovil; Milošević, Maja

2017-04-01

Beryl minerals of Serbia were slightly studied in the last century and despite that there is some obtainable data about main characteristics there is a limited amount of information about foreign molecules in the mineral structure. Two beryl samples from different locations in Serbia were examined in detail but infrared spectroscopy (IR) and spectrophotometry (VIS) was used for determination of foreign molecules and ions in the structure and the obtained data is shown in this paper. The infrared (IR) and visible spectra (VIS) of two natural beryl samples indicate the presence of two types of water molecule, Fe2+, Fe3+ ions and CO3. The spectra of two types of water molecules can be recognized with molecular fundamental vibrations at 3687 cm-1 (asymmetric stretching) for type I, at 3574 cm-1 and 3585 cm-1 both symmetric stretching, and with deformation vibrations at 1627 cm-1 and 1632 cm-1 for type II. In range of symmetric stretching there is broad vibrational band which can be explained by presence of water molecules type II near alkali ions. Overtones and combinations of these fundamental vibrations have been identified. The type I molecules have their C2 symmetry axes perpendicular to the crystal C6 axis, while the type II molecules are rotated by 90 degrees and have their C2 symmetry axes parallel to the crystal C6 axis. Vibrational absorption frequency of 1425 cm-1 indicate the presence of CO3. Pale blue beryl is colored according to the relative intensities of two spectral features attributable to iron ions: a) a broad band in the extraordinary ray (Er) at 16000 cm-1 due to Fe2+ in a channel site and b) a broad band in range of 22500-31400 cm-1 in both ordinary ray (Or) and Er due to octahedral Fe3+ in the Al3+ site. Two other features, also attributable to iron, do not produce any visible coloration: a) an absorption edge at 12350 cm-1 in Or is due to Fe2+ in the octahedral site and b) a broad band in Er and Or, centered around 12350 cm-1, is due to Fe2+ in

Observation of several chlorine nitrate (ClONO2) bands in stratospheric infrared spectra

NASA Technical Reports Server (NTRS)

Zander, R.; Rinsland, C. P.; Farmer, C. B.; Brown, L. R.; Norton, R. H.

1986-01-01

Four of the most prominent and sharpest infrared absorption features of chlorine nitrate at 780.2, 807.7, 809.4, and 1292.6/cm have been observed in a series of infrared solar spectra obtained at an unapodized spectral resolution of 0.01/cm, using the Atmospheric Trace Molecule Spectroscopy instrument from on-board Sapcelab 3. A quantitative analysis of the nu4 Q branch at 780.2/cm has provided insight into the concentration of ClONO2 between 19 and 40 km altitude. While the mean profile deduced from three sunset occultations near 30 deg N latitude exhibits a shape close to that predicted by model calculations, its concentrations in the 20 to 32 km altitude range are, however, about 30 percent larger, reaching a peak concentration of 9 x 10 to the 8th molecules/cu cm at 25 km. The concentrations above 32 km, deduced from one sunrise occultation at 47 deg JS, are even larger than the corresponding sunset values at 30 deg N latitude. Some of these discrepancies may be caused by the rather large uncertainty in the assumed Q branch strength.

Post-maximum Near-infrared Spectra of SN 2014J: A Search for Interaction Signatures

NASA Astrophysics Data System (ADS)

Sand, D. J.; Hsiao, E. Y.; Banerjee, D. P. K.; Marion, G. H.; Diamond, T. R.; Joshi, V.; Parrent, J. T.; Phillips, M. M.; Stritzinger, M. D.; Venkataraman, V.

2016-05-01

We present near-infrared (NIR) spectroscopic and photometric observations of the nearby Type Ia SN 2014J. The 17 NIR spectra span epochs from +15.3 to +92.5 days after B-band maximum light, while the {{JHK}}s photometry include epochs from -10 to +71 days. These data are used to constrain the progenitor system of SN 2014J utilizing the Paβ line, following recent suggestions that this phase period and the NIR in particular are excellent for constraining the amount of swept-up hydrogen-rich material associated with a non-degenerate companion star. We find no evidence for Paβ emission lines in our post-maximum spectra, with a rough hydrogen mass limit of ≲ 0.1 M ⊙, which is consistent with previous limits in SN 2014J from late-time optical spectra of the Hα line. Nonetheless, the growing data set of high-quality NIR spectra holds the promise of very useful hydrogen constraints. Based on observations obtained at the Gemini Observatory under program GN-2014A-Q-8 (PI: Sand). Gemini is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).

Simulations of the infrared, Raman, and 2D-IR photon echo spectra of water in nanoscale silica pores

DOE PAGES

Burris, Paul C.; Laage, Damien; Thompson, Ward H.

2016-05-20

Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this Paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for water confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D 2O is considered. An empirical mapping approach ismore » used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of water in mesoporous silica reported in the literature. The key effect of confinement on the water spectrum is a vibrational blueshift for OH groups that are closest to the pore interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. Lastly, the simulated spectra indicate that it should be possible to probe the slower spectral diffusion of confined water compared to the bulk liquid by analysis of the 2D-IR spectra.« less

Simulations of the infrared, Raman, and 2D-IR photon echo spectra of water in nanoscale silica pores.

PubMed

Burris, Paul C; Laage, Damien; Thompson, Ward H

2016-05-21

Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for water confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D2O is considered. An empirical mapping approach is used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of water in mesoporous silica reported in the literature. The key effect of confinement on the water spectrum is a vibrational blueshift for OH groups that are closest to the pore interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. The simulated spectra indicates that it should be possible to probe the slower spectral diffusion of confined water compared to the bulk liquid by analysis of the 2D-IR spectra.

Simulations of the infrared, Raman, and 2D-IR photon echo spectra of water in nanoscale silica pores

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burris, Paul C.; Thompson, Ward H., E-mail: wthompson@ku.edu; Laage, Damien, E-mail: damien.laage@ens.fr

2016-05-21

Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for water confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D{sub 2}O is considered. An empirical mapping approach ismore » used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of water in mesoporous silica reported in the literature. The key effect of confinement on the water spectrum is a vibrational blueshift for OH groups that are closest to the pore interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. The simulated spectra indicates that it should be possible to probe the slower spectral diffusion of confined water compared to the bulk liquid by analysis of the 2D-IR spectra.« less

Infrared and Microwave Spectra of Ne-WATER Complex

NASA Astrophysics Data System (ADS)

Liu, Xunchen; Thomas, Javix; Xu, Yunjie; Hou, Dan; Li, Hui

2016-06-01

The binary complex of rare gas atom and water is an ideal model to study the anisotropic potential energy surface of van der Waals interaction and the large amplitude motion. Although Xe-H_2O, Kr-H_2O, Ar-H_2O, Ar-D_2O and even Ne-D_2O complexes were studied by microwave or high resolution infrared spectroscopy, the lighter Ne-H_2O complex has remained unidentified. In this talk, we will present the theoretical and experimental investigation of the Ne-H_2O complex. A four-dimension PES for H_2O-Ne which only depended on the intramolecular (Q2) normal-mode coordinate of H2O monomer was calculated in this work to determine the rovibrational energy levels and mid-infrared transitions. Aided with the calculated transitions, we were able to assigned the high resolution mid-infrared spectra of both 20Ne-H_2O and 22Ne-H_2O complexes that are generated with a pulsed supersonic molecular beam in a multipass direct absorption spectrometer equiped with an external cavity quantum cascade laser at 6 μm. Several bands of both para and ortho Ne-H2O were assigned and fitted using the Hamiltonian with strong Coriolis and angular-radical coupling terms. The predicted groud state energy levels are then confirmed by the J=1-0 and J=2-1 transitions measurement using a cavity based Fourier transform microwave spectrometer.

Infrared-transmission spectra and hydrogen content of hydrogenated amorphous silicon

NASA Astrophysics Data System (ADS)

Hu, Yuehi; Chen, Guanghua; Wu, Yueying; Yin, Shengyi; Gao, Zhuo; Wang, Qing; Song, Xuemei; Deng, Jinxiang

2004-05-01

In this paper, two kinds of methods of calculating the hydrogen content of a-Si:H thin film by means of the wagging mode and the stretching modes of infrared-transmission spectra, are investigated. The reason for the difference in these two calculation results is analyzed. If the contents of SiH2 and (SiH2) n are indicated in terms of a structure factor F=(/840+/880)//2000, it is shown that the calculation results obtained from the two different methods are almost equal when the refractive index n is approximately 3.4 or the fitting thickness is between 0.71 and 0.89 μm in the case of a small F. It is shown that the ways of fabrication of thin film can influences silicon-hydrogen bonding configuration of a-Si: H film, and different ways of fabrication can lead to different contents of SiH2 and (SiH2) n . The uniformity of the thin film with a big F is bad. In this case, there is great difference between the thickness measured by the SurfCom408A surface profile apparatus and the thickness obtained by fitting the fringes; and the hydrogen contents of a-Si:H films obtained by means of the wagging mode and the stretching modes are different, too. But the fabrication of the MWECR CVD assisted by CAT CVD can effectively restrain the formation of SiH2 and (SiH2) n .

Analysis of fingerprints features of infrared spectra of various processed products of Radix Aconiti kusnezoffii

NASA Astrophysics Data System (ADS)

Tu-ya; Yang, Ping; Sun, Su-qin; Zhou, Qun; Bao, Xiao-hua; Noda, Isao

2010-06-01

Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR)) are employed to analyze various processed products and ether extracts of Radix Aconiti kusnezoffii. There is a resemblance among the spectra of different processed products. The major difference lies in the absorption peak at 1641 cm -1 in the IR spectra, which reflects the transformation of raw aconite to the processed products. There are distinctive differences in the absorption peaks in the range of 1800-1500 cm -1 in the second derivative spectra, which has better resolution, of different processed products. 2D-IR spectra, which elevate the resolution further, can present even more differences among the products in the range of 1800-800 cm -1. Analysis of ether extracts of various processed products proves that there are alcohols, esters, carboxylic acids or ketones in all of them. However, their contents in different samples have obvious differences. With the advantages of high resolution, high-speed and convenience, IR can quickly and precisely distinguish various processed products of Radix A. kusnezoffii, and can be applied to predict the tendency of transformation of the complicated chemical mixture systems under heat perturbation.

Compositional Analyses and Implications of Visible/Near-Infrared Spectra of Outer Irregular Jovian Satellites

NASA Astrophysics Data System (ADS)

Vilas, Faith; Hendrix, Amanda

2017-10-01

The existence of a visible-near infrared absorption feature attributed to aqueous alteration products has been suggested in both grey and reddened broadband photometry of some outer irregular jovian satellites. Moderate resolution VNIR narrowband spectroscopy was obtained of the jovian irregular satellites JVI Himalia, JVII Elara, JVIII Pasiphae, JIX Sinope, JX Lysithea, JXI Carme, JXII Ananke and JXVII Callirrhoe in 2006, 2008, 2009, and 2010 using the MMT Observatory facility Red Channel spectrograph to confirm the presence of this feature. The spectra are centered near 0.64 μm in order to cover the 0.7-μm feature entirely (generally ranging from 0.57 to 0.83 μm). The spectra generally have a dispersion/element of ~0.6 nm (6Å) some spectra are smoothed. These spectra sample three prograde (i = 28o), four retrograde (i = 149o, 165o) and one independent satellite.We observe these findings among the spectra:- An absorption feature centered near 0.7 µm exists in the spectra of the three prograde (i = 28o) satellites. This feature is spectrally broader than the 0.7-µm feature observed in C-complex asteroids. None appears spectrally reddened. This suggests that these prograde satellites have a common parent body.- A different absorption feature appears in the spectra of the three retrograde (i = 149o) satellites, also suggesting a common parent body. Varying reddening is observed. This feature is similar in spectral location and width to the 0.7-µm feature.- Reddening is observed in the individual observation of JXI Carme (i = 165o), and independent satellite JIX Sinope, similar to the D-class asteroid spectra dominating the Trojan population. A suggested absorption feature is being investigated.Mixing modeling of combinations of both expected and proposed compositions including carbonaceous materials, phyllosilicates, mafic silicates, and other opaque materials, is currently underway. Results will be reported and discussed at the meeting.Acknowledgments: The

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket arrives at the pad. 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 arrives at the pad. 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.

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.

[On-line monitoring of biomass in 1,3-propanediol fermentation by Fourier-transformed near-infrared spectra analysis].

PubMed

Wang, Lu; Liu, Tao; Chen, Yang; Sun, Yaqin; Xiu, Zhilong

2017-01-25

Biomass is an important parameter reflecting the fermentation dynamics. Real-time monitoring of biomass can be used to control and optimize a fermentation process. To overcome the deficiencies of measurement delay and manual errors from offline measurement, we designed an experimental platform for online monitoring the biomass during a 1,3-propanediol fermentation process, based on using the fourier-transformed near-infrared (FT-NIR) spectra analysis. By pre-processing the real-time sampled spectra and analyzing the sensitive spectra bands, a partial least-squares algorithm was proposed to establish a dynamic prediction model for the biomass change during a 1,3-propanediol fermentation process. The fermentation processes with substrate glycerol concentrations of 60 g/L and 40 g/L were used as the external validation experiments. The root mean square error of prediction (RMSEP) obtained by analyzing experimental data was 0.341 6 and 0.274 3, respectively. These results showed that the established model gave good prediction and could be effectively used for on-line monitoring the biomass during a 1,3-propanediol fermentation process.

Infrared (2.08-14 micron) spectra of powered stony meteorites

NASA Technical Reports Server (NTRS)

Salisbury, J. W.; Daria, D. M.; Jarosewich, E.

1991-01-01

Infrared biconical reflectance spectra of 60 powdered meteorite samples, representing 50 different stony meteorites, were measured as analogues of asteroidal regolith. Representative samples were measured in directional hemispherical reflectance to assure that Kirchhoff's Law can be used to predict relative emissivity from the reflectance spectra. These spectral data confirm that the O-H fundamental absorption band near 2.9 microns is an extremely sensitive indicator of incipient alteration, which often has taken place in powdered meteorite samples exposed only to water vapor in the air. Such non-carbonaceous samples typically contain less than 1 percent water by weight. Likewise, the C-H fundamental absorption bands near 3.4 and 3.5 microns are equally sensitive indicators of contamination with volatile hydrocarbons, which can also be absorbed from the air. The heavy, macromolecular hydrocarbons native to chondrites do not display such heavy bands, making detection of these bands in remote sensing of asteroids unlikely. Despite the spectral artifacts introduced by alteration and hydrocarbon contamination, powdered stony meteorites display a wide variety of real spectral features that can be used for their identification, including residual reststrahlen bands, absorption bands, and the Christiansen feature. Researchers found that the wavelengths of the peaks or troughs of each of these spectral features can be used independently to infer meteorite composition, but the best results are obtained when the entire spectral curve is used, or at least the portion of it encompassed by the 8 to 14 micron atmospheric window, in a digital search library.

Infrared and near infrared emission spectra of TeH and TeD

NASA Astrophysics Data System (ADS)

Yu, Shanshan; Shayesteh, Alireza; Fu, Dejian; Bernath, Peter F.

2005-04-01

The vibration-rotation emission spectra for the X2Π ground state and the near infrared emission spectra of the X2Π 1/2- X2Π 3/2 system of the TeH and TeD free radicals have been measured at high resolution using a Fourier transform spectrometer. TeH and TeD were generated in a tube furnace with a DC discharge of a flowing mixture of argon, hydrogen (or deuterium), and tellurium vapor. In the infrared region, for the X2Π 3/2 spin component we observed the 1-0, 2-1, and 3-2 vibrational bands for most of the eight isotopologues of TeH and the 1-0 and 2-1 bands for three isotopologues of TeD. For the X2Π 1/2- X2Π 3/2 transition, we observed the 0-0 and 1-1 bands for TeH and the 0-0, 1-1, and 2-2 bands for TeD. Except for a few lines, the tellurium isotopic shift was not resolved for the X2Π 1/2- X2Π 3/2 transitions of TeH and TeD. Local perturbations with Δ v = 2 between the two spin components of the X2Π state of TeH were found: X2Π 1/2, v = 0 with X2Π 3/2, v = 2; X2Π 1/2, v = 1 with X2Π 3/2, v = 3. The new data were combined with the previous data from the literature and two kinds of fits (Hund's case (a) and Hund's case (c)) were carried out for each of the 10 observed isotopologues: 130TeD, 128TeD, 126TeD, 130TeH, 128TeH, 126TeH, 125TeH, 124TeH, 123TeH, and 122TeH.

Update from the Analysis of High Resolution Propane Spectra and the Interpretation of Titan's Infrared Spectra

NASA Technical Reports Server (NTRS)

Klavans, V.; Nixon, C.; Hewagama, T.; Jennings, D. E.

2012-01-01

Titan has an extremely thick atmosphere dominated by nitrogen, but includes a range of trace species such as hydrocarbons and nitriles. One such hydrocarbon is propane (C3H8). Propane has 21 active IR bands covering broad regions of the mid-infrared. Therefore, its ubiquitous signature may potentially mask weaker signatures of other undetected species with important roles in Titan's chemistry. Cassini's Composite Infrared Spectrometer (CIRS) observations of Titan's atmosphere hint at the presence of such molecules. Unfortunately, C3H8 line atlases for the vibration bands V(sub 8), V(sub 21), V(sub 20), and V(sub 7) (869, 922, 1054, and 1157 per centimeter, respectively) are not currently available for subtracting the C3H8 signal to reveal, or constrain, the signature of underlying chemical species. Using spectra previously obtained by Jennings, D. E., et al. at the McMath-Pierce FTIR at Kitt Peak, AZ, as the source and automated analysis utilities developed for this application, we are compiling an atlas of spectroscopic parameters for propane that characterize the ro-vibrational transitions in the above bands. In this paper, we will discuss our efforts for inspecting and fitting the aforementioned bands, present updated results for spectroscopic parameters including absolute line intensities and transition frequencies in HITRAN and GEISA formats, and show how these optical constants will be used in searching for other trace chemical species in Titan's atmosphere. Our line atlas for the V(sub 21) band contains a total number of 2971 lines. The band integrated strength calculated for the V(sub 21) band is 1.003 per centimeter per (centimeter-atm).

Empirical measurement and model validation of infrared spectra of contaminated surfaces

NASA Astrophysics Data System (ADS)

Archer, Sean; Gartley, Michael; Kerekes, John; Cosofret, Bogdon; Giblin, Jay

2015-05-01

Liquid-contaminated surfaces generally require more sophisticated radiometric modeling to numerically describe surface properties. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) Model utilizes radiative transfer modeling to generate synthetic imagery. Within DIRSIG, a micro-scale surface property model (microDIRSIG) was used to calculate numerical bidirectional reflectance distribution functions (BRDF) of geometric surfaces with applied concentrations of liquid contamination. Simple cases where the liquid contamination was well described by optical constants on optically at surfaces were first analytically evaluated by ray tracing and modeled within microDIRSIG. More complex combinations of surface geometry and contaminant application were then incorporated into the micro-scale model. The computed microDIRSIG BRDF outputs were used to describe surface material properties in the encompassing DIRSIG simulation. These DIRSIG generated outputs were validated with empirical measurements obtained from a Design and Prototypes (D&P) Model 102 FTIR spectrometer. Infrared spectra from the synthetic imagery and the empirical measurements were iteratively compared to identify quantitative spectral similarity between the measured data and modeled outputs. Several spectral angles between the predicted and measured emissivities differed by less than 1 degree. Synthetic radiance spectra produced from the microDIRSIG/DIRSIG combination had a RMS error of 0.21-0.81 watts/(m2-sr-μm) when compared to the D&P measurements. Results from this comparison will facilitate improved methods for identifying spectral features and detecting liquid contamination on a variety of natural surfaces.

Copernicus spectra and infrared photometry of 42 Orionis

NASA Technical Reports Server (NTRS)

Johnson, H. M.; Snow, T. P., Jr.; Gehrz, R. D.; Hackwell, J. A.

1977-01-01

The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. Infrared photometry is presented which suggests that the ratio of total to selective extinction ranges from 3 to 3.5 for the interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components.

Copernicus spectra and infrared photometry of 42 Orionis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, H.M.; Snow, T.P. Jr.; Gehrz, R.D.

1977-04-01

The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. We present infrared photometry which suggests that 3 less than or equal to R less than or equal to 3.5 for themore » interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components.« less

Infrared absorption spectra of N(CxF2x+1)3, x = 2-5 perfluoroamines

NASA Astrophysics Data System (ADS)

Bernard, François; Papanastasiou, Dimitrios K.; Papadimitriou, Vassileios C.; Burkholder, James B.

2018-05-01

Infrared absorption spectra of the perfluoroamines (N(C2F5)3, N(C3F7)3, N(C4F9)3, and N(C5F11)3) were measured over the 500-4000 cm-1 spectral region at 294 K using Fourier transform infrared (FTIR) spectroscopy at 1 cm-1 resolution. Spectral measurements were performed using static measurements of dilute perfluoroamines mixtures and by infusion of the pure compound into a calibrated gas flow. The perfluoroamines absorb strongly in the "atmospheric window" with integrated band strengths (10-17 cm2 molecule-1 cm-1) between 570 and 1500 cm-1 of 59.9, 74.9, 88.9, and 98.7 for N(C2F5)3, N(C3F7)3, N(C4F9)3, and N(C5F11)3, respectively. Radiative efficiencies (RE) for the perfluoroamines were estimated to be 0.61, 0.75, 0.87, and 0.95 W m-2 ppb-1 for atmospherically well-mixed conditions and including a +10% stratospheric temperature correction for N(C2F5)3, N(C3F7)3, N(C4F9)3, and N(C5F11)3, respectively. Theoretical calculations of the perfluoroamines were performed at the B97-1/6-311++G(2df,2p) level of theory and optimized perfluoroamine geometries, vibrational band positions, and band strengths are reported. The theoretically calculated infrared spectra are in good agreement with the experimental spectra, while comparison of individual bands was not attempted due to the significant overlap of vibrational bands in the experimental spectra.

Near-infrared reflectance spectra-applications to problems in asteroid-meteorite relationships

NASA Technical Reports Server (NTRS)

Mcfadden, Lucy A.; Chamberlin, Alan; Vilas, Faith

1991-01-01

Near-infrared spectral reflectance data were collected at the Infrared Telescope Facility (IRTF) at Mauna Kea Observatories in 1985 and 1986 for the purpose of searching the region near the 3:1 Kirkwood gap for asteroids with the spectral signatures of ordinary chondrite parent bodies. Twelve reflectance spectra are observed. The presence of ordinary chondrite parent bodies among this specific set of observed asteroids is not obvious, though the sample is biased towards the larger asteroids in the region due to limitations imposed by detector sensitivity. The data set, which was acquired with the same instrumentation used for the 52-color asteroid survey (Bell et al., 1987), also presents some additional findings. The range of spectral characteristics that exist among asteroids of the same taxonomic type is noted. Conclusions based on the findings are discussed.

Infrared Spectra and Optical Constants of Elusive Amorphous Methane

NASA Technical Reports Server (NTRS)

Gerakines, Perry A.; Hudson, Reggie L.

2015-01-01

New and accurate laboratory results are reported for amorphous methane (CH4) ice near 10 K for the study of the interstellar medium (ISM) and the outer Solar System. Near- and mid-infrared (IR) data, including spectra, band strengths, absorption coefficients, and optical constants, are presented for the first time for this seldom-studied amorphous solid. The apparent IR band strength near 1300 cm(exp -1) (7.69 micrometer) for amorphous CH4 is found to be about 33% higher than the value long used by IR astronomers to convert spectral observations of interstellar CH4 into CH4 abundances. Although CH4 is most likely to be found in an amorphous phase in the ISM, a comparison of results from various laboratory groups shows that the earlier CH4 band strength at 1300 cm(exp -1) (7.69 micrometer) was derived from IR spectra of ices that were either partially or entirely crystalline CH4 Applications of the new amorphous-CH4 results are discussed, and all optical constants are made available in electronic form.

Infrared Spectra and Band Strengths of CH3SH, an Interstellar Molecule

NASA Technical Reports Server (NTRS)

Hudson, R. L.

2016-01-01

Three solid phases of CH3SH (methanethiol or methyl mercaptan) have been prepared and their mid-infrared spectra recorded at 10-110 degrees Kelvin, with an emphasis on the 17-100 degrees Kelvin region. Refractive indices have been measured at two temperatures and used to estimate ice densities and infrared band strengths. Vapor pressures for the two crystalline phases of CH3SH at 110 degrees Kelvin are estimated. The behavior of amorphous CH3SH on warming is presented and discussed in terms of Ostwald's step rule. Comparisons to CH3OH under similar conditions are made, and some inconsistencies and ambiguities in the CH3SH literature are examined and corrected.

Infrared Spectra and Optical Constants of Astronomical Ices: II. Ethane and Ethylene

NASA Technical Reports Server (NTRS)

Hudson, Reggie L.; Gerakines, Perry A.; Moore, M. H.

2014-01-01

Infrared spectroscopic observations have established the presence of hydrocarbon ices on Pluto and other TNOs, but the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. In this paper we present our recent measurements of near- and mid-infrared optical constants for ethane (C2H6) and ethylene (C2H4) in multiple ice phases and at multiple temperatures. As in our recent work on acetylene (C2H2), we also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible, and electronic versions of our new results are made available.

The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene

NASA Astrophysics Data System (ADS)

Mackie, Cameron J.; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Mattioda, Andrew L.; Buma, Wybren Jan; Lee, Timothy J.; Tielens, Alexander G. G. M.

2016-08-01

The study of interstellar polycyclic aromatic hydrocarbons (PAHs) relies heavily on theoretically predicted infrared spectra. Most earlier studies use scaled harmonic frequencies for band positions and the double harmonic approximation for intensities. However, recent high-resolution gas-phase experimental spectroscopic studies have shown that the harmonic approximation is not sufficient to reproduce experimental results. In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs, showing the importance of including anharmonicities into the theoretical calculations. In this paper, we continue this work by extending the study to include five non-linear PAHs (benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene), thereby allowing us to make a full assessment of how edge structure, symmetry, and size influence the effects of anharmonicities. The theoretical anharmonic spectra are compared to spectra obtained under matrix isolation low-temperature conditions, low-resolution, high-temperature gas-phase conditions, and high-resolution, low-temperature gas-phase conditions. Overall, excellent agreement is observed between the theoretical and experimental spectra although the experimental spectra show subtle but significant differences.

The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene.

PubMed

Mackie, Cameron J; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Mattioda, Andrew L; Buma, Wybren Jan; Lee, Timothy J; Tielens, Alexander G G M

2016-08-28

The study of interstellar polycyclic aromatic hydrocarbons (PAHs) relies heavily on theoretically predicted infrared spectra. Most earlier studies use scaled harmonic frequencies for band positions and the double harmonic approximation for intensities. However, recent high-resolution gas-phase experimental spectroscopic studies have shown that the harmonic approximation is not sufficient to reproduce experimental results. In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs, showing the importance of including anharmonicities into the theoretical calculations. In this paper, we continue this work by extending the study to include five non-linear PAHs (benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene), thereby allowing us to make a full assessment of how edge structure, symmetry, and size influence the effects of anharmonicities. The theoretical anharmonic spectra are compared to spectra obtained under matrix isolation low-temperature conditions, low-resolution, high-temperature gas-phase conditions, and high-resolution, low-temperature gas-phase conditions. Overall, excellent agreement is observed between the theoretical and experimental spectra although the experimental spectra show subtle but significant differences.

Raman and infrared spectra and theoretical calculations of dipicolinic acid, dinicotinic acid, and their dianions

NASA Astrophysics Data System (ADS)

McCann, Kathleen; Laane, Jaan

2008-11-01

The Raman and infrared spectra of dipicolinic acid (DPA) and dinicotinic acid (DNic) and their salts (CaDPA, Na 2DPA, and CaDNic) have been recorded and the spectra have been assigned. Ab initio and DFT calculations were carried out to predict the structures and vibrational spectra and were compared to the experimental results. Because of extensive intermolecular hydrogen bonding in the crystals of these molecules, the calculated structures and spectra for the individual molecules agree only moderately well with the experimental values. Theoretical calculations were also carried out for DPA dimers and DPA·2H 2O to better understand the intermolecular interactions. The spectra do show that DPA and its calcium salt, which are present in anthrax spores, can be distinguished from the very similar DNic and CaDNic.

Photoluminescence Study of Gallium Nitride Thin Films Obtained by Infrared Close Space Vapor Transport.

PubMed

Santana, Guillermo; de Melo, Osvaldo; Aguilar-Hernández, Jorge; Mendoza-Pérez, Rogelio; Monroy, B Marel; Escamilla-Esquivel, Adolfo; López-López, Máximo; de Moure, Francisco; Hernández, Luis A; Contreras-Puente, Gerardo

2013-03-15

Photoluminescence (PL) studies in GaN thin films grown by infrared close space vapor transport (CSVT-IR) in vacuum are presented in this work. The growth of GaN thin films was done on a variety of substrates like silicon, sapphire and fused silica. Room temperature PL spectra of all the GaN films show near band-edge emission (NBE) and a broad blue and green luminescence (BL, GL), which can be seen with the naked eye in a bright room. The sample grown by infrared CSVT on the silicon substrate shows several emission peaks from 2.4 to 3.22 eV with a pronounced red shift with respect to the band gap energy. The sample grown on sapphire shows strong and broad ultraviolet emission peaks (UVL) centered at 3.19 eV and it exhibits a red shift of NBE. The PL spectrum of GaN films deposited on fused silica exhibited a unique and strong blue-green emission peak centered at 2.38 eV. The presence of yellow and green luminescence in all samples is related to native defects in the structure such as dislocations in GaN and/or the presence of amorphous phases. We analyze the material quality that can be obtained by CSVT-IR in vacuum, which is a high yield technique with simple equipment set-up, in terms of the PL results obtained in each case.

Photoluminescence Study of Gallium Nitride Thin Films Obtained by Infrared Close Space Vapor Transport

PubMed Central

Santana, Guillermo; de Melo, Osvaldo; Aguilar-Hernández, Jorge; Mendoza-Pérez, Rogelio; Monroy, B. Marel; Escamilla-Esquivel, Adolfo; López-López, Máximo; de Moure, Francisco; Hernández, Luis A.; Contreras-Puente, Gerardo

2013-01-01

Photoluminescence (PL) studies in GaN thin films grown by infrared close space vapor transport (CSVT-IR) in vacuum are presented in this work. The growth of GaN thin films was done on a variety of substrates like silicon, sapphire and fused silica. Room temperature PL spectra of all the GaN films show near band-edge emission (NBE) and a broad blue and green luminescence (BL, GL), which can be seen with the naked eye in a bright room. The sample grown by infrared CSVT on the silicon substrate shows several emission peaks from 2.4 to 3.22 eV with a pronounced red shift with respect to the band gap energy. The sample grown on sapphire shows strong and broad ultraviolet emission peaks (UVL) centered at 3.19 eV and it exhibits a red shift of NBE. The PL spectrum of GaN films deposited on fused silica exhibited a unique and strong blue-green emission peak centered at 2.38 eV. The presence of yellow and green luminescence in all samples is related to native defects in the structure such as dislocations in GaN and/or the presence of amorphous phases. We analyze the material quality that can be obtained by CSVT-IR in vacuum, which is a high yield technique with simple equipment set-up, in terms of the PL results obtained in each case. PMID:28809356

Infrared Spectra and Band Strengths of Amorphous and Crystalline N2O

NASA Technical Reports Server (NTRS)

Hudson, R. L.; Loeffler, M. J.; Gerakines, P. A.

2017-01-01

Infrared transmission spectra from 4000 to 400 cm (exp -1), and associated band strengths and absorption coefficients, are presented for the first time for both amorphous and crystalline N2O. Changes in the spectra as a function of ice thickness and ice temperature are shown. New measurements of density, refractive index, and specific refraction are reported for amorphous and crystalline N2O. Comparisons are made to published results, and the most-likely reason for some recent disagreements in the literature is discussed. As with CO2, its isoelectronic congener, the formation of amorphous N2O is found to require greater care than the formation of amorphous solids from more-polar molecules.

Profiles of Stratospheric Chlorine Nitrate from ATMOS/ATLAS 1 Infrared Solar Occultation Spectra

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Mahieu, E.; Goldman, A.; Ko, M. K. W.; Rodriguez, J. M.; Sze, N. D.

1994-01-01

Stratospheric volume mixing ration profiles of chlorine nitrate have been retrieved from 0.01-cm(sub -1) resolution infrared solar occutation spectra recorded at latitudes between 14 degrees N and 54 degrees S by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS 1 shuttle mission (March 24 to April 2, 1992).

Analysis of torsional spectra of molecules with two internal C/3v/ rotors. III - Far-infrared and gas phase Raman spectra of dimethylamine-d0, -d3, and -d6

NASA Technical Reports Server (NTRS)

Durig, J. R.; Griffin, M. G.; Groner, P.

1977-01-01

The Raman spectra of gaseous dimethylamine-d0, -d3, and -d6 have been recorded between 0 and 4000/cm. The far-infrared spectra have been recorded between 300 and 100/cm. Considerable torsional data are reported and used to characterize the torsional potential function based on a semi-rigid model. The average effective V3 for the dimethylamines was found to be 1052 plus or minus 12/cm. The cos-cos coupling term was approximately 15% of the effective V3, whereas the sine-sine coupling term was of an order of magnitude smaller for (CH3)2NH and (CD3)2NH. However, for the mixed isotope the sine-sine term was found to be negligible and the cos-cos about one-half the value obtained for the other two isotopes.

AKARI/IRC NEAR-INFRARED SPECTRAL ATLAS OF GALACTIC PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohsawa, Ryou; Onaka, Takashi; Sakon, Itsuki

2016-04-15

Near-infrared (2.5–5.0 μm) low-resolution (λ/Δλ ∼ 100) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a 1′ × 1′ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due to a slit. The spectra show emission features including hydrogen recombination lines and the 3.3–3.5 μm hydrocarbon features. The intensity and equivalent width of the emission features were measured by spectral fitting. We made a catalog providing unique information on the investigation of the near-infrared emission ofmore » PNe. In this paper, details of the observations and characteristics of the catalog are described.« less

Laboratory Gas-phase Infrared Spectra of Two Astronomically Relevant PAH Cations: Diindenoperylene, {{\\rm{C}}}_{32}{{\\rm{H}}}_{16}^{+} and Dicoronylene, {{\\rm{C}}}_{48}{{\\rm{H}}}_{20}^{+}

NASA Astrophysics Data System (ADS)

Zhen, Junfeng; Candian, Alessandra; Castellanos, Pablo; Bouwman, Jordy; Linnartz, Harold; Tielens, Alexander G. G. M.

2018-02-01

The first gas-phase infrared spectra of two isolated astronomically relevant and large polycyclic aromatic hydrocarbon (PAH) cations—diindenoperylene (DIP) and dicoronylene (DC)—in the 530–1800 cm‑1 (18.9‑5.6 μm) range—are presented. Vibrational band positions are determined for comparison to the aromatic infrared bands. The spectra are obtained via infrared multiphoton dissociation spectroscopy of ions stored in a quadrupole ion trap using the intense and tunable radiation of the free electron laser for infrared experiments (FELIX). DIP+ shows its main absorption peaks at 737 (13.57), 800 (12.50), 1001 (9.99), 1070 (9.35), 1115 (8.97), 1152 (8.68), 1278 (7.83), 1420 (7.04), and 1550 (6.45) cm‑1(μm), in good agreement with density functional theory (DFT) calculations that are uniformly scaled to take anharmonicities into account. DC+ has its main absorption peaks at 853 (11.72), 876 (11.42), 1032 (9.69), 1168 (8.56), 1300 (7.69), 1427 (7.01), and 1566 (6.39) cm‑1(μm), which also agree well with the scaled DFT results presented here. The DIP+ and DC+ spectra are compared with the prominent infrared features observed toward NGC 7023. This results both in matches and clear deviations. Moreover, in the 11.0–14.0 μm region, specific bands can be linked to CH out-of-plane (oop) bending modes of different CH edge structures in large PAHs. The molecular origin of these findings and their astronomical relevance are discussed.

Predicting ambient aerosol Thermal Optical Reflectance (TOR) measurements from infrared spectra: organic carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2014-11-01

Organic carbon (OC) can constitute 50% or more of the mass of atmospheric particulate matter. Typically, the organic carbon concentration is measured using thermal methods such as Thermal-Optical Reflectance (TOR) from quartz fiber filters. Here, methods are presented whereby Fourier Transform Infrared (FT-IR) absorbance spectra from polytetrafluoroethylene (PTFE or Teflon) filters are used to accurately predict TOR OC. Transmittance FT-IR analysis is rapid, inexpensive, and non-destructive to the PTFE filters. To develop and test the method, FT-IR absorbance spectra are obtained from 794 samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites sampled during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to artifact-corrected TOR OC. The FTIR spectra are divided into calibration and test sets by sampling site and date which leads to precise and accurate OC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), low bias (0.02 μg m-3, all μg m-3 values based on the nominal IMPROVE sample volume of 32.8 m-3), low error (0.08 μg m-3) and low normalized error (11%). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision and accuracy to collocated TOR measurements. FT-IR spectra are also divided into calibration and test sets by OC mass and by OM / OC which reflects the organic composition of the particulate matter and is obtained from organic functional group composition; this division also leads to precise and accurate OC predictions. Low OC concentrations have higher bias and normalized error due to TOR analytical errors and artifact correction errors, not due to the range of OC mass of the samples in the calibration set. However, samples with low OC mass can be used to predict samples with high OC mass indicating that the

Theoretical Infrared Spectra for Polycyclic Aromatic Hydrocarbon Neutrals, Cations and Anions

NASA Technical Reports Server (NTRS)

Langhoff, Stephen R.

1995-01-01

Calculations are carried out using density functional theory (DFT) to determine the harmonic frequencies and intensities of the neutrals and cations of thirteen polycyclic aromatic hydrocarbons (PAHs) up to the size of ovalene. Calculations are also carried out for a few PAH anions. The DFT harmonic frequencies, when uniformly scaled by the factor of 0.958 to account primarily for anharmonicity, agree with the matrix isolation fundamentals to within an average error of about 10 per centimeter. Electron correlation is found to significantly reduce the intensities of many of the cation harmonics, bringing them into much better agreement with the available experimental data. While the theoretical infrared spectra agree well with the experimental data for the neutral systems and for many of the cations, there are notable discrepancies with the experimental matrix isolation data for some PAH cations that are difficult to explain in terms of limitations in the calculations. In agreement with previous theoretical work, the present calculations show that the relative intensities for the astronomical unidentified infrared (UIR) bands agree reasonably well with those for a distribution of polycyclic aromatic hydrocarbon (PAH) cations, but not with a distribution of PAH neutrals. We also observe that the infrared spectra of highly symmetrical cations such as coronene agree much better with astronomical observations than do those of, for example, the polyacenes such as tetracene and pentacene. The total integrated intensities for the neutral species are found to increase linearly with size, while the total integrated intensities are much larger for the cations and scale more nearly quadratically with size. We conclude that emission from moderate-sized highly symmetric PAH cations such as coronene and larger could account for the UIR bands.

Structures and vibrational spectra of pinacol.. 1. Infrared and matrix infrared spectra of monomeric pinacol. Ab initio calculations on conformers and vibrational frequencies

NASA Astrophysics Data System (ADS)

Dahlqvist, Martti; Hotokka, Matti; Räsänen, Markku

1998-04-01

The infrared spectra of monomeric pinacol molecules (2,3-dimethyl-2,3-butanediol; (CH 3) 2C(OH)C(OH)(CH 3) 2) have been recorded in the gas phase and dilute nonpolar solutions, and in an argon matrix. The vibrational data are consistent with the intramolecularly hydrogen-bonded G-type (gauche with respect to the central C-C bond) conformers and there is no evidence for the T-type (trans with respect to the central C-C bond) conformers, which have been observed in the condensed phases. This was confirmed by studying the infrared region 835-815 cm -1, which was found to be the most indicative to show spectral changes within the type of the conformers. In this region the band of the T-type conformers (assigned to the hybridized asymmetric vibration of the central CC and CO stretching modes) disappears when going from the condensed phases to phases, where pinacol molecules are monomeric. Ab initio HF/6-311G** (MP2/6-311G**) calculations support the experimental findings; the calculated relative energies for the tGg', gGg', g'Gg', tTt, and gTg' conformers are 0.0 (0.0), 3.4 (3.4), 5.1 (5.9), 7.9 (11.3), and 12.0 (14.0) kJ mol -1, respectively. Consequently, only the G-type conformers are sufficiently populated to give rise to observable spectral lines. Both experimental findings and theoretical calculations demonstrated that the bands in the argon matrix spectrum of pinacol are due to the most stable tGg' conformer. Although the ab initio calculations predict that also the gGg' and g'Gg' conformers are present in the gas phase and in dilute nonpolar solutions their existence could not be confirmed experimentally. Hence, we conclude that the conformation sensitive bands may coincide in the spectra. The HF/6-311G** ab initio calculations for vibrational frequencies of pinacol are consistent with this conclusion, suggesting only small differences between the wavenumbers of the G-type conformers. Pinacol does not show infrared-induced photorotamerization in the low

Information content in Iris spectra. [Infrared Interferometer Spectrometer of Nimbus 4 satellite

NASA Technical Reports Server (NTRS)

Price, J. C.

1975-01-01

Spectra from the satellite instrument Iris (infrared interferometer spectrometer) were examined to find the number of independent variables needed to describe the broad-band high-resolution spectral data. The radiated power in the atmospheric window from 771 to 981 per cm was the first parameter chosen for fitting observed spectra. At succeeding levels of analysis, the residual variability (observed spectrum minus best-fit spectrum) in an ensemble of observations was partitioned into spectral eigenvectors. The eigenvector describing the largest fraction of this variability was examined for a strong spectral signature; the power in the corresponding spectral band was then used as the next fitting parameter. The measured power in nine spectral intervals, when it was inserted in the spectral-fitting functions, was adequate to describe most spectra to within the noise level of Iris. Considerations of relative signal strength and scales of atmospheric variability suggest a combination sounder (multichannel, broad field of view) scanner (window channel, small field of view) as an efficient observing instrument.

Tautomerism and infrared spectra of 2-thiopurine: an experimental matrix isolation and theoretical ab initio and density functional theory study

NASA Astrophysics Data System (ADS)

Stepanenko, Tetyana; Lapinski, Leszek; Nowak, Maciej J.; Kwiatkowski, Józef S.; Leszczynski, Jerzy

2001-02-01

Infrared spectra of 2-thiopurine (2-mercaptopurine, 2-purinethiol ) isolated in low-temperature Ar and N 2 matrixes are reported. These spectra indicate that the compound adopts exclusively the thiol N9H tautomeric form. The theoretical calculations of relative energies of 2-thiopurine tautomers have been carried out at the MP4(SDTQ)//HF level using the 6-31G( d, p) basis set. The thiol N9H tautomer was predicted to be the most stable of all isomers of 2-thiopurine. The infrared spectra of the tautomers of 2-thiopurine have been calculated at the DFT(B3LYP)/6-31G( d, p) level. Good agreement between the experimental spectra and the spectra calculated for thiol N9H tautomer supported the identification of the dominant tautomer. It has also allowed for the reliable assignment of the bands observed in the experimental IR spectrum.

Automatic Preocessing of Impact Ionization Mass Spectra Obtained by Cassini CDA

NASA Astrophysics Data System (ADS)

Villeneuve, M.

2015-12-01

Since Cassini's arrival at Saturn in 2004, the Comic Dust Analyzer (CDA) has recorded nearly 200,000 mass spectra of dust particles. A majority of this data has been collected in Saturn's diffuse E ring where sodium salts embedded in water ice particles indicate that many particles are in fact frozen droplets from Enceladus' subsurface ocean that have been expelled from cracks in the icy crust. So far only a small fraction of the obtained spectra have been processed because the steps in processing the spectra require human manipulation. We developed an automatic processing pipeline for CDA mass spectra which will consistently analyze this data. The preprocessing steps are to de-noise the spectra, determine and remove the baseline, calculate the correct stretch parameter, and finally to identify elements and compounds in the spectra. With the E ring constantly evolving due to embedded active moons, this data will provide valuable information about the source of the E ring, the subsurface of Saturn's ice moon Enceladus, as well as about the dynamics of the ring itself.

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE prepare to begin further processing of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. Sections of the transportation canister used in the move are in the foreground. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE prepare to begin further processing of the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. Sections of the transportation canister used in the move are in the foreground. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

Artifact Correction in Temperature-Dependent Attenuated Total Reflection Infrared (ATR-IR) Spectra.

PubMed

Sobieski, Brian; Chase, Bruce; Noda, Isao; Rabolt, John

2017-08-01

A spectral processing method was developed and tested for analyzing temperature-dependent attenuated total reflection infrared (ATR-IR) spectra of aliphatic polyesters. Spectra of a bio-based, biodegradable polymer, 3.9 mol% 3HHx poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] (PHBHx), were analyzed and corrected prior to analysis using two-dimensional correlation spectroscopy (2D-COS). Removal of the temperature variation of diamond absorbance, correction of the baseline, ATR correction, and appropriate normalization were key to generating more reliable data. Both the processing steps and order were important. A comparison to differential scanning calorimetry (DSC) analysis indicated that the normalization method should be chosen with caution to avoid unintentional trends and distortions of the crystalline sensitive bands.

Infrared spectra of group III A metal oxides

NASA Technical Reports Server (NTRS)

Lynch, D. A., Jr.

1972-01-01

The measurement of infrared frequencies of metal-oxygen species which could be formed in the matrix and to investigate with an oxygen-18 enrichment study the controversy on the vibrational assignments for the suboxide. Several new molecules, Al3O2, Ga3O, In3O, In4O2, IntaO, IntaO2, and In2WO4, were found by mass spectrometric sampling to exist in extremely minor concentrations in the vapor phase. The latter three species were formed by reaction with the crucible materials and were unimportant for an infrared analysis. The infrared spectroscopic measurements were obtained by the matrix isolation technique of molecular beam sampling. The MO2 species were formed by direct reaction between metal and O2 in the matrix. A C2v structure and an O-M-O bond angle near 40 deg was favored for these molecules by analogy with a similar investigation of the alkali metals. The vibrational frequencies which were determined are given.

Application of class-modelling techniques to infrared spectra for analysis of pork adulteration in beef jerkys.

PubMed

Kuswandi, Bambang; Putri, Fitra Karima; Gani, Agus Abdul; Ahmad, Musa

2015-12-01

The use of chemometrics to analyse infrared spectra to predict pork adulteration in the beef jerky (dendeng) was explored. In the first step, the analysis of pork in the beef jerky formulation was conducted by blending the beef jerky with pork at 5-80 % levels. Then, they were powdered and classified into training set and test set. The second step, the spectra of the two sets was recorded by Fourier Transform Infrared (FTIR) spectroscopy using atenuated total reflection (ATR) cell on the basis of spectral data at frequency region 4000-700 cm(-1). The spectra was categorised into four data sets, i.e. (a) spectra in the whole region as data set 1; (b) spectra in the fingerprint region (1500-600 cm(-1)) as data set 2; (c) spectra in the whole region with treatment as data set 3; and (d) spectra in the fingerprint region with treatment as data set 4. The third step, the chemometric analysis were employed using three class-modelling techniques (i.e. LDA, SIMCA, and SVM) toward the data sets. Finally, the best result of the models towards the data sets on the adulteration analysis of the samples were selected and the best model was compared with the ELISA method. From the chemometric results, the LDA model on the data set 1 was found to be the best model, since it could classify and predict 100 % accuracy of the sample tested. The LDA model was applied toward the real samples of the beef jerky marketed in Jember, and the results showed that the LDA model developed was in good agreement with the ELISA method.

[Apply fourier transform infrared spectra coupled with two-dimensional correlation analysis to study the evolution of humic acids during composting].

PubMed

Bu, Gui-jun; Yu, Jing; Di, Hui-hui; Luo, Shi-jia; Zhou, Da-zhai; Xiao, Qiang

2015-02-01

The composition and structure of humic acids formed during composting play an important influence on the quality and mature of compost. In order to explore the composition and evolution mechanism, municipal solid wastes were collected to compost and humic and fulvic acids were obtained from these composted municipal solid wastes. Furthermore, fourier transform infrared spectra and two-dimensional correlation analysis were applied to study the composition and transformation of humic and fulvic acids during composting. The results from fourier transform infrared spectra showed that, the composition of humic acids was complex, and several absorbance peaks were observed at 2917-2924, 2844-2852, 2549, 1662, 1622, 1566, 1454, 1398, 1351, 990-1063, 839 and 711 cm(-1). Compared to humic acids, the composition of fulvci acids was simple, and only three peaks were detected at 1725, 1637 and 990 cm(-1). The appearance of these peaks showed that both humic and fulvic acids comprised the benzene originated from lignin and the polysaccharide. In addition, humic acids comprised a large number of aliphatic and protein which were hardly detected in fulvic acids. Aliphatic, polysaccharide, protein and lignin all were degraded during composting, however, the order of degradation was different between humic and fulvci acids. The result from two-dimensional correlation analysis showed that, organic compounds in humic acids were degraded in the following sequence: aliphatic> protein> polysaccharide and lignin, while that in fulvic acids was as following: protein> polysaccharide and aliphatic. A large number of carboxyl, alcohols and ethers were formed during the degradation process, and the carboxyl was transformed into carbonates. It can be concluded that, fourier transform infrared spectra coupled with two-dimensional correlation analysis not only can analyze the function group composition of humic substances, but also can characterize effectively the degradation sequence of these

Near-infrared reflectance spectra of mixtures of kaolin-group minerals: Use in clay mineral studies

USGS Publications Warehouse

Crowley, James K.; Vergo, Norma

1988-01-01

Near-infrared (NIR) reflectance spectra for mixtures of ordered kaolinite and ordered dickite have been found to simulate the spectral response of disordered kaolinite. The amount of octahedral vacancy disorder in nine disordered kaolinite samples was estimated by comparing the sample spectra to the spectra of reference mixtures. The resulting estimates are consistent with previously published estimates of vacancy disorder for similar kaolin minerals that were modeled from calculated X-ray diffraction patterns. The ordered kaolinite and dickite samples used in the reference mixtures were carefully selected to avoid undesirable particle size effects that could bias the spectral results.NIR spectra were also recorded for laboratory mixtures of ordered kaolinite and halloysite to assess whether the spectra could be potentially useful for determining mineral proportions in natural physical mixtures of these two clays. Although the kaolinite-halloysite proportions could only be roughly estimated from the mixture spectra, the halloysite component was evident even when halloysite was present in only minor amounts. A similar approach using NIR spectra for laboratory mixtures may have applications in other studies of natural clay mixtures.

Infrared and Raman spectra of N-acetyl- L-amino acid methylamides with aromatic side groups

NASA Astrophysics Data System (ADS)

Matsuura, Hiroatsu; Hasegawa, Kodo; Miyazawa, Tatsuo

Infrared and Raman spectra of N-acetyl- L-phenylalanine methylamide, N-acetyl- L-tyrosine methylamide and N-acetyl- L-tryptophan methylamide, as model compounds of aromatic amino acid residues in proteins, were measured in the solid state and in methanol solutions. Vibrational assignments of the spectra were made by utilizing the deuteration effect and by comparison with the spectra of related compounds which include toluene, p-cresol and 3-methylindole. The amide I, III and IV bands were strong in Raman scattering, but other characteristic amide bands were ill-defined. In the Raman spectra of methanol solutions, only the bands due to the aromatic side group vibrations were markedly observed, but those due to the peptide backbone vibrations were very weak, suggesting the coexistence of various molecular conformations in solution.

Pinus taeda L. wood property calibrations based on variable numbers of near infrared spectra per core and cores per plantation

Treesearch

Laurence R. Schimleck; Justin A. Tyson; David Jones; Gary F. Peter; Richard F. Daniels; Alexander III Clark

2007-01-01

Near infrared (NIR) spectroscopy provides a rapid, non-destructive method for the estimation of several wood properties of increment cores. MR spectra are collected from adjacent sections of the same core; however, not all spectra are required for calibration purposes as spectra from the same core are autocorrelated. Previously, we showed that wood property...

A setup for simultaneous measurement of infrared spectra and light scattering signals: Watching amyloid fibrils grow from intact proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yang; Maurer, Jürgen; Roth, Andreas

A setup for the simultaneous measurement of mid-infrared spectra and static light scattering is described that can be used for the analysis of the formation of nanoscale and microscopic aggregates from smaller molecules to biopolymers. It can be easily integrated into sample chambers of infrared spectrometers or combined with laser beams from tunable infrared lasers. Here, its use for the analysis of the formation of amyloid fibrils from intact proteins is demonstrated. The formation of amyloid fibrils or plaques from proteins is a widespread and pathogenetic relevant process, and a number of diseases are caused and correlated with the depositionmore » of amyloid fibrils in cells and tissues. The molecular mechanisms of these transformations, however, are still unclear. We report here the simultaneous measurement of infrared spectra and static light scattering for the analysis of fibril formation from egg-white lysozyme. The transformation of the native form into non-native forms rich in β-sheet structure is measured by analysis of the amide I spectral region in the infrared spectra, which is sensitive for local structures. At the same time, light scattering signals at forward direction as well as the forward/backward ratio, which are sensitive for the number of scattering centers and their approximate sizes, respectively, are collected for the analysis of fibril growth. Thermodynamic and kinetic parameters as well as mechanistic information are deduced from the combination of the two complementary techniques.« less

A setup for simultaneous measurement of infrared spectra and light scattering signals: Watching amyloid fibrils grow from intact proteins

NASA Astrophysics Data System (ADS)

Li, Yang; Maurer, Jürgen; Roth, Andreas; Vogel, Vitali; Winter, Ernst; Mäntele, Werner

2014-08-01

A setup for the simultaneous measurement of mid-infrared spectra and static light scattering is described that can be used for the analysis of the formation of nanoscale and microscopic aggregates from smaller molecules to biopolymers. It can be easily integrated into sample chambers of infrared spectrometers or combined with laser beams from tunable infrared lasers. Here, its use for the analysis of the formation of amyloid fibrils from intact proteins is demonstrated. The formation of amyloid fibrils or plaques from proteins is a widespread and pathogenetic relevant process, and a number of diseases are caused and correlated with the deposition of amyloid fibrils in cells and tissues. The molecular mechanisms of these transformations, however, are still unclear. We report here the simultaneous measurement of infrared spectra and static light scattering for the analysis of fibril formation from egg-white lysozyme. The transformation of the native form into non-native forms rich in β-sheet structure is measured by analysis of the amide I spectral region in the infrared spectra, which is sensitive for local structures. At the same time, light scattering signals at forward direction as well as the forward/backward ratio, which are sensitive for the number of scattering centers and their approximate sizes, respectively, are collected for the analysis of fibril growth. Thermodynamic and kinetic parameters as well as mechanistic information are deduced from the combination of the two complementary techniques.

Quantitative Infrared Absorption Spectra and Vibrational Assignments of Crotonaldehyde and Methyl Vinyl Ketone Using Gas-Phase Mid-Infrared, Far-Infrared, and Liquid Raman Spectra: s-cis vs s-trans Composition Confirmed via Temperature Studies and ab Initio Methods.

PubMed

Lindenmaier, Rodica; Williams, Stephen D; Sams, Robert L; Johnson, Timothy J

2017-02-16

Methyl vinyl ketone (MVK) and crotonaldehyde are chemical isomers; both are also important species in tropospheric chemistry. We report quantitative vapor-phase infrared spectra of crotonaldehyde and MVK vapors over the 540-6500 cm -1 range. Vibrational assignments of all fundamental modes are made for both molecules on the basis of far- and mid-infrared vapor-phase spectra, liquid Raman spectra, along with density functional theory and ab initio MP2 and high energy-accuracy compound theoretical models (W1BD). Theoretical results indicate that at room temperature the crotonaldehyde equilibrium mixture is approximately 97% s-trans and only 3% s-cis conformer. Nearly all observed bands are thus associated with the s-trans conformer, but a few appear to be uniquely associated with the s-cis conformer, notably ν 16 c at 730.90 cm -1 , which displays a substantial intensity increase with temperature (70% upon going from 5 to 50 o C). The intensity of the corresponding mode of the s-trans conformer decreases with temperature. Under the same conditions, the MVK equilibrium mixture is approximately 69% s-trans conformer and 31% s-cis. W1BD calculations indicate that for MVK this is one of those (rare) cases where there are comparable populations of both conformers, approximately doubling the number of observed bands and exacerbating the vibrational assignments. We uniquely assign the bands associated with both the MVK s-cis conformer as well as those of the s-trans, thus completing the vibrational analyses of both conformers from the same set of experimental spectra. Integrated band intensities are reported for both molecules along with global warming potential values. Using the quantitative IR data, potential bands for atmospheric monitoring are also discussed.

Quantitative Infrared Absorption Spectra and Vibrational Assignments of Crotonaldehyde and Methyl Vinyl Ketone Using Gas-Phase Mid-Infrared, Far-Infrared, and Liquid Raman Spectra: s-cis vs s-trans Composition Confirmed via Temperature Studies and ab Initio Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindenmaier, Rodica; Williams, Stephen D.; Sams, Robert L.

Methyl vinyl ketone (MVK) and crotonaldehyde are chemical isomers; both are also important species in tropospheric chemistry. We report quantitative vapor-phase infrared spectra of crotonaldehyde and MVK vapors over the 540-6500 cm-1 range. Vibrational assignments of all fundamental modes are made for both molecules based on far- and mid-infrared vapor-phase spectra, liquid Raman spectra, along with density functional theory and ab initio MP2 and high energy-accuracy compound theoretical models (W1BD). Theoretical results indicate that at room temperature the crotonaldehyde equilibrium mixture is approximately 97% s-trans and only 3% s-cis conformer. Nearly all observed bands are thus associated with the s-transmore » conformer, but a few appear to be uniquely associated the s-cis conformer, notably ν16c at 730.90 cm-1, which displays a substantial intensity increase with temperature (62% upon going from 5 to 50 oC). The intensity of the corresponding mode of the s-trans conformer decreases with temperature. Under the same conditions, the MVK equilibrium mixture is approximately 69% s-trans conformer and 31% s-cis. W1BD calculations indicate that for MVK this is one of those (rare) cases where there are comparable populations of both conformers, ~doubling the number of observed bands and exacerbating the vibrational assignments. We uniquely assign the bands associated with both the MVK s-cis conformer as well as those of the s-trans, thus completing the vibrational analyses of both conformers from the same set of experimental spectra. Integrated band intensities are reported for both molecules along with global warming potential values. Using the quantitative IR data, potential bands for atmospheric monitoring are also discussed.« less

Theoretical modeling of infrared spectra of aspirin and its deuterated derivative

NASA Astrophysics Data System (ADS)

Boczar, Marek; Wójcik, Marek J.; Szczeponek, Krzysztof; Jamróz, Dorota; Zi e̡ba, Adam; Kawałek, Bożena

2003-01-01

Theoretical simulation of the νs stretching band is presented for aspirin (acetylsalicylic acid) and its OD derivative at 300 and 77 K. The simulation takes into account an adiabatic coupling between the high-frequency O-H(D) stretching and the low-frequency intermolecular O⋯O stretching modes, linear and quadratic distortions of the potential energy for the low-frequency vibrations in the excited state of the O-H(D) stretching vibration, resonance interaction between two hydrogen bonds in the dimer, and Fermi resonance between the O-H(D) stretching and the overtone of the O-H(D) bending vibrations. The effect of deuteration and the temperature has been successfully reproduced by our model calculations. Infrared, far-infrared, Raman and low-frequency Raman spectra of the polycrystalline aspirin have been measured. The geometry and experimental frequencies are compared with the results of our B3LYP/6-31++G** calculations.

Study on Properties of Energy Spectra of the Molecular Crystals

NASA Astrophysics Data System (ADS)

Pang, Xiao-Feng; Chen, Xiang-Rong

The energy-spectra of nonlinear vibration of molecular crystals such as acetanilide have been calculated by using discrete nonlinear Schrödinger equation appropriate to the systems, containing various interactions. The energy levels including higher excited states are basically consistent with experimental values obtained by infrared absorption and Raman scattering in acetanilide. We further give the features of distribution of the energy-spectra for the acetanilide. Using the energy spectra we also explained well experimental results obtained by Careri et al..

Estimation of Venus wind velocities from high-resolution infrared spectra. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Smith, M. A. H.

1978-01-01

Zonal velocity profiles in the Venus atmosphere above the clouds were estimated from measured asymmetries of HCl and HF infrared absorption lines in high-resolution Fourier interferometer spectra of the planet. These asymmetries are caused by both pressure-induced shifts in the positions of the hydrogen-halide lines perturbed by CO2 and Doppler shifts due to atmospheric motions. Particularly in the case of the HCl 2-0 band, the effects of the two types of line shifts can be easily isolated, making it possible to estimate a profile of average Venus equatorial zonal velocity as a function of pressure in the region roughly 60 to 70 km above the surface of the planet. The mean profiles obtained show strong vertical shear in the Venus zonal winds near the cloud-top level, and both the magnitude and direction of winds at all levels in this region appear to vary greatly with longitude relative to the sub-solar point.

FBRDLR: Fast blind reconstruction approach with dictionary learning regularization for infrared microscopy spectra

NASA Astrophysics Data System (ADS)

Liu, Tingting; Liu, Hai; Chen, Zengzhao; Chen, Yingying; Wang, Shengming; Liu, Zhi; Zhang, Hao

2018-05-01

Infrared (IR) spectra are the fingerprints of the molecules, and the spectral band location closely relates to the structure of a molecule. Thus, specimen identification can be performed based on IR spectroscopy. However, spectrally overlapping components prevent the specific identification of hyperfine molecular information of different substances. In this paper, we propose a fast blind reconstruction approach for IR spectra, which is based on sparse and redundant representations over a dictionary. The proposed method recovers the spectrum with the discrete wavelet transform dictionary on its content. The experimental results demonstrate that the proposed method is superior because of the better performance when compared with other state-of-the-art methods. The method the authors used remove the instrument aging issue to a large extent, thus leading the reconstruction IR spectra a more convenient tool for extracting features of an unknown material and interpreting it.

Fourier transform infrared reflectance spectra of latent fingerprints: a biometric gauge for the age of an individual.

PubMed

Hemmila, April; McGill, Jim; Ritter, David

2008-03-01

To determine if changes in fingerprint infrared spectra linear with age can be found, partial least squares (PLS1) regression of 155 fingerprint infrared spectra against the person's age was constructed. The regression produced a linear model of age as a function of spectrum with a root mean square error of calibration of less than 4 years, showing an inflection at about 25 years of age. The spectral ranges emphasized by the regression do not correspond to the highest concentration constituents of the fingerprints. Separate linear regression models for old and young people can be constructed with even more statistical rigor. The success of the regression demonstrates that a combination of constituents can be found that changes linearly with age, with a significant shift around puberty.

Multivariate Curve Resolution Methods Illustrated Using Infrared Spectra of an Alcohol Dissolved in Carbon Tetrachloride

ERIC Educational Resources Information Center

Grung, Bjorn; Nodland, Egil; Forland, Geir Martin

2007-01-01

The analysis of the infrared spectra of an alcohol dissolved in carbon tetrachloride gives a better understanding of the various multivariate curve resolution methods. The resulting concentration profile is found to be very useful for calculating the degree of association and equilibrium constants of different compounds.

The detection of enhanced carbon monoxide abundances in remotely sensed infrared spectra of a forest fire smoke plume

NASA Astrophysics Data System (ADS)

McMillan, W. W.; Strow, L. L.; Smith, W. L.; Revercomb, H. E.; Huang, H. L.

Nadir looking infrared spectra of a forest fire smoke plume off the south shore of Long Island, New York, were obtained from a NASA ER-2 aircraft during two spatially coincident over-flights on the morning of August 25, 1995. These spectra exhibit enhanced CO column densities at the same geographic locations over the smoke plume on both over-flights with a peak CO column density ˜2.6 × 1018 cm-2, ˜6σ above the clear air background. Meteorological conditions suggest the smoke plume was confined to the planetary boundary layer (PBL), pressures ≥ 850 mb, and perhaps to a thin region near the top of the PBL. Constraining the excess CO to the PBL yields a CO mixing ratio ˜1,400 ppbv. Further constraining the CO to the model layer nearest the top of the PBL, 852-878 mb, yields-4,300 ppbv. From the spatial overlap of the spectra, the estimated width of the CO rich portion of the plume is ≤ 2.8 km vs. a plume width of ˜5 km in GOES-8 satellite visible images.

Stratospheric and mesospheric pressure-temperature profiles from rotational analysis of CO2 lines in atmospheric trace molecule spectroscopy/ATLAS 1 infrared solar occultation spectra

NASA Technical Reports Server (NTRS)

Stiller, G. P.; Gunson, M. R.; Lowes, L. L.; Abrams, M. C.; Raper, O. F.; Farmer, C. B.; Zander, R.; Rinsland, C. P.

1995-01-01

A simple, classical, and expedient method for the retrieval of atmospheric pressure-temperature profiles has been applied to the high-resolution infrared solar absorption spectra obtained with the atmospheric trace molecule spectroscopy (ATMOS) instrument. The basis for this method is a rotational analysis of retrieved apparent abundances from CO2 rovibrational absorption lines, employing existing constituent concentration retrieval software used in the analysis of data returned by ATMOS. Pressure-temperature profiles derived from spectra acquired during the ATLAS 1 space shuttle mission of March-April 1992 are quantitatively evaluated and compared with climatological and meteorological data as a means of assessing the validity of this approach.

New Fe i Level Energies and Line Identifications from Stellar Spectra. II. Initial Results from New Ultraviolet Spectra of Metal-poor Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Ruth C.; Kurucz, Robert L.; Ayres, Thomas R., E-mail: peterson@ucolick.org

2017-04-01

The Fe i spectrum is critical to many areas of astrophysics, yet many of the high-lying levels remain uncharacterized. To remedy this deficiency, Peterson and Kurucz identified Fe i lines in archival ultraviolet and optical spectra of metal-poor stars, whose warm temperatures favor moderate Fe i excitation. Sixty-five new levels were recovered, with 1500 detectable lines, including several bound levels in the ionization continuum of Fe i. Here, we extend the previous work by identifying 59 additional levels, with 1400 detectable lines, by incorporating new high-resolution UV spectra of warm metal-poor stars recently obtained by the Hubble Space Telescope Imagingmore » Spectrograph. We provide gf values for these transitions, both computed as well as adjusted to fit the stellar spectra. We also expand our spectral calculations to the infrared, confirming three levels by matching high-quality spectra of the Sun and two cool stars in the H -band. The predicted gf values suggest that an additional 3700 Fe i lines should be detectable in existing solar infrared spectra. Extending the empirical line identification work to the infrared would help confirm additional Fe i levels, as would new high-resolution UV spectra of metal-poor turnoff stars below 1900 Å.« less

New Fe I Level Energies and Line Identifications from Stellar Spectra. II. Initial Results from New Ultraviolet Spectra of Metal-poor Stars

NASA Astrophysics Data System (ADS)

Peterson, Ruth C.; Kurucz, Robert L.; Ayres, Thomas R.

2017-04-01

The Fe I spectrum is critical to many areas of astrophysics, yet many of the high-lying levels remain uncharacterized. To remedy this deficiency, Peterson & Kurucz identified Fe I lines in archival ultraviolet and optical spectra of metal-poor stars, whose warm temperatures favor moderate Fe I excitation. Sixty-five new levels were recovered, with 1500 detectable lines, including several bound levels in the ionization continuum of Fe I. Here, we extend the previous work by identifying 59 additional levels, with 1400 detectable lines, by incorporating new high-resolution UV spectra of warm metal-poor stars recently obtained by the Hubble Space Telescope Imaging Spectrograph. We provide gf values for these transitions, both computed as well as adjusted to fit the stellar spectra. We also expand our spectral calculations to the infrared, confirming three levels by matching high-quality spectra of the Sun and two cool stars in the H-band. The predicted gf values suggest that an additional 3700 Fe I lines should be detectable in existing solar infrared spectra. Extending the empirical line identification work to the infrared would help confirm additional Fe I levels, as would new high-resolution UV spectra of metal-poor turnoff stars below 1900 Å.

Theoretical modeling of infrared spectra of the hydrogen and deuterium bond in aspirin crystal

NASA Astrophysics Data System (ADS)

Ghalla, Houcine; Rekik, Najeh; Michta, Anna; Oujia, Brahim; Flakus, Henryk T.

2010-01-01

An extended quantum theoretical approach of the ν IR lineshape of cyclic dimers of weakly H-bonded species is proposed. We have extended a previous approach [M.E.-A. Benmalti, P. Blaise, H.T. Flakus, O. Henri-Rousseau, Chem. Phys. 320 (2006) 267] by accounting for the anharmonicity of the slow mode which is described by a "Morse" potential in order to reproduce the polarized infrared spectra of the hydrogen and deuterium bond in acetylsalicylic acid (aspirin) crystals. From comparison of polarized IR spectra of isotopically neat and isotopically diluted aspirin crystals it resulted that centrosymmetric aspirin dimer was the bearer of the crystal main spectral properties. In this approach, the adiabatic approximation is performed for each separate H-bond bridge of the dimer and a strong non-adiabatic correction is introduced into the model via the resonant exchange between the fast mode excited states of the two moieties. Within the strong anharmonic coupling theory, according to which the X-H→⋯Y high-frequency mode is anharmonically coupled to the H-bond bridge, this model incorporated the Davydov coupling between the excited states of the two moieties, the quantum direct and indirect dampings and the anharmonicity for the H-bond bridge. The spectral density is obtained within the linear response theory by Fourier transform of the damped autocorrelation functions. The evaluated spectra are in fairly good agreement with the experimental ones by using a minimum number of independent parameters. The effect of deuteration has been well reproduced by reducing simply the angular frequency of the fast mode and the anharmonic coupling parameter.

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.

KENNEDY SPACE CENTER, FLA. - A solid rocket booster (SRB) for the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF) arrives at Launch Complex 17-B, Cape Canaveral Air Force Station. The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. 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. - A solid rocket booster (SRB) for the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF) arrives at Launch Complex 17-B, Cape Canaveral Air Force Station. The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. 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.

KENNEDY SPACE CENTER, FLA. - In Hangar A&E, Cape Canaveral Air Force Station, the upper canister is lowered toward the Space Infrared Telescope Facility (SIRTF) below. After encapsulation 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, the upper canister is lowered toward the Space Infrared Telescope Facility (SIRTF) below. After encapsulation 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.

KENNEDY SPACE CENTER, FLA. - Workers on Launch Complex 17-B, Cape Canaveral Air Force Station, prepare the first stage of a Delta II rocket for its lift up 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. - Workers on Launch Complex 17-B, Cape Canaveral Air Force Station, prepare the first stage of a Delta II rocket for its lift up 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.

KENNEDY SPACE CENTER, FLA. - Working from a stand, technicians fasten the upper portion of the canister to the middle panels 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. - Working from a stand, technicians fasten the upper portion of the canister to the middle panels 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.

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.

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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is raised off the transporter before lifting and moving it 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 raised off the transporter before lifting and moving it 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.

KENNEDY SPACE CENTER, FLA. - Workers at Hangar A&E, Cape Canaveral Air Force Station, place the middle row of panels to encapsulate 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. - Workers at Hangar A&E, Cape Canaveral Air Force Station, place the middle row of panels to encapsulate 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.

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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is lifted up the mobile service tower. In the background is pad 17-A. 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 lifted up the mobile service tower. In the background is pad 17-A. 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.

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.

KENNEDY SPACE CENTER, FLA. - A worker at Hangar A&E, Cape Canaveral Air Force Station, place the lower panels of 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, place the lower panels of 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.

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 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 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.

KENNEDY SPACE CENTER, FLA. - In Hangar A&E, Cape Canaveral Air Force Station, the upper canister is mated to the middle panels 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. - In Hangar A&E, Cape Canaveral Air Force Station, the upper canister is mated to the middle panels 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.

KENNEDY SPACE CENTER, FLA. - Workers at Hangar A&E, Cape Canaveral Air Force Station, lower the upper canister toward the Space Infrared Telescope Facility (SIRTF) below. After encapsulation 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. - Workers at Hangar A&E, Cape Canaveral Air Force Station, lower the upper canister toward the Space Infrared Telescope Facility (SIRTF) below. After encapsulation 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.

On the nitrogen-induced far-infrared absorption spectra

NASA Technical Reports Server (NTRS)

Dore, P.; Filabozzi, A.

1987-01-01

The rototranslational absorption spectrum of gaseous N2 is analyzed, considering quadrupolar and hexadecapolar induction mechanisms. The available experimental data are accounted for by using a line-shape analysis in which empirical profiles describe the single-line translational profiles. Thus, a simple procedure is derived that allows the prediction of the N2 spectrum at any temperature. On the basis of the results obtained for the pure gas, a procedure to compute the far-infrared spectrum of the N2-Ar gaseous mixture is also proposed. The good agreement between computed and experimental N2-Ar data indicates that it is possible to predict the far-infrared absorption induced by N2 on the isotropic polarizability of any interacting partner.

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.

Chemometric correlation of shelf life, quality measurements, and visible-near infrared spectra of pasteurized eggs

USDA-ARS?s Scientific Manuscript database

A twelve week study was conducted on the egg albumen from both pasteurized and non-pasteurized shell eggs using visible-near infrared spectroscopy. Correlation of the chemical changes detected in the spectra to the measurement of Haugh units (measure of interior egg quality) was carried out using pr...

Infrared and Microwave Spectra and Force Field of DBO: The Coriolis Interaction between the nu1 and nu2 + nu3 States.

PubMed

Kawashima; Colarusso; Zhang; Bernath; Hirota

1998-11-01

The nu1 and nu3 bands of D11BO and the nu1 band of D10BO were observed by using an infrared diode laser spectrometer. The DBO molecule was generated by an ac discharge in a mixture of BCl3, D2, O2, and He. As inferred previously, a strong Coriolis interaction was in fact found to take place between the nu1 and nu2 + nu3 states, and an analysis of the observed nu1 spectra, which explicitly took into account this Coriolis interaction, predicted the pure rotational transition frequencies of DBO in the nu1 state. Pure rotational lines were then detected by microwave spectroscopy, confirming the validity of the infrared assignment. In the microwave experiment DBO molecules were generated by a discharge in a mixture of B2D6 and O2. The three fundamental bands and a hot band of D11BO, as well as the nu1 and nu3 bands of D10BO, were subsequently recorded in emission with a Fourier transform infrared spectrometer. DBO molecules were generated by the reaction of D2 with HBO at temperatures above 800 degreesC in a ceramic tube furnace. All of the observed spectra were simultaneously subjected to a least-squares analysis to obtain molecular parameters in the ground, nu1, nu2, nu3, and nu2 + nu3 states. The results thus obtained improved the force field and molecular structure of the HBO/DBO molecules reported in a previous study (Y. Kawashima, Y. Endo, and E. Hirota, 1989, J. Mol. Spectrosc. 133, 116-127). Copyright 1998 Academic Press.

Infrared and Microwave Spectra and Force Field of DBO: The Coriolis Interaction between the ν 1and ν 2+ ν 3States

NASA Astrophysics Data System (ADS)

Kawashima, Yoshiyuki; Colarusso, Pina; Zhang, K. Q.; Bernath, Peter; Hirota, Eizi

1998-11-01

The ν1and ν3bands of D11BO and the ν1band of D10BO were observed by using an infrared diode laser spectrometer. The DBO molecule was generated by an ac discharge in a mixture of BCl3, D2, O2, and He. As inferred previously, a strong Coriolis interaction was in fact found to take place between the ν1and ν2+ ν3states, and an analysis of the observed ν1spectra, which explicitly took into account this Coriolis interaction, predicted the pure rotational transition frequencies of DBO in the ν1state. Pure rotational lines were then detected by microwave spectroscopy, confirming the validity of the infrared assignment. In the microwave experiment DBO molecules were generated by a discharge in a mixture of B2D6and O2. The three fundamental bands and a hot band of D11BO, as well as the ν1and ν3bands of D10BO, were subsequently recorded in emission with a Fourier transform infrared spectrometer. DBO molecules were generated by the reaction of D2with HBO at temperatures above 800°C in a ceramic tube furnace. All of the observed spectra were simultaneously subjected to a least-squares analysis to obtain molecular parameters in the ground, ν1, ν2, ν3, and ν2+ ν3states. The results thus obtained improved the force field and molecular structure of the HBO/DBO molecules reported in a previous study (Y. Kawashima, Y. Endo, and E. Hirota, 1989,J. Mol. Spectrosc.133, 116-127).

Quantitative Comparison of Tandem Mass Spectra Obtained on Various Instruments

NASA Astrophysics Data System (ADS)

Bazsó, Fanni Laura; Ozohanics, Oliver; Schlosser, Gitta; Ludányi, Krisztina; Vékey, Károly; Drahos, László

2016-08-01

The similarity between two tandem mass spectra, which were measured on different instruments, was compared quantitatively using the similarity index (SI), defined as the dot product of the square root of peak intensities in the respective spectra. This function was found to be useful for comparing energy-dependent tandem mass spectra obtained on various instruments. Spectral comparisons show the similarity index in a 2D "heat map", indicating which collision energy combinations result in similar spectra, and how good this agreement is. The results and methodology can be used in the pharma industry to design experiments and equipment well suited for good reproducibility. We suggest that to get good long-term reproducibility, it is best to adjust the collision energy to yield a spectrum very similar to a reference spectrum. It is likely to yield better results than using the same tuning file, which, for example, does not take into account that contamination of the ion source due to extended use may influence instrument tuning. The methodology may be used to characterize energy dependence on various instrument types, to optimize instrumentation, and to study the influence or correlation between various experimental parameters.

VizieR Online Data Catalog: Low-resolution near-infrared stellar spectra from CIBER (Kim+, 2017)

NASA Astrophysics Data System (ADS)

Kim, M. G.; Lee, H. M.; Arai, T.; Bock, J.; Cooray, A.; Jeong, W.-S.; Kim, S. J.; Korngut, P.; Lanz, A.; Lee, D. H.; Lee, M. G.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Onishi, Y.; Shirahata, M.; Smidt, J.; Tsumura, K.; Yamamura, I.; Zemcov, M.

2017-06-01

We present flux-calibrated near-infrared spectra of 105 stars from 0.8{<=}λ{<=}1.8μm with spectral resolution 15{<=}λ/Δλ{<=}30 over the range. The Low-Resolution Spectrometer (LRS) is one of the four optical instruments of the Cosmic Infrared Background Experiment (CIBER) payload; the others are a narrowband spectrometer and two wide-field imagers. The LRS is a prism-dispersed spectrometer with five rectangular 5.35°*2.8' slits imaging a 5.8°*5.8° field of view. The detector has 256*256 pixels at a pixel scale of 1.36'*1.36'. CIBER has flown four times (2009 February, 2010 July, 2012 March, and 2013 June) with apogees and total exposure times of over 325km and ~240s, respectively, in the first three flights and of 550km and 335s in the final, non-recovered flight. Due to spurious signal contamination from thermal emission from the shock-heated rocket skin, we do not use the first flight data in this work. The star spectral types are determined by fitting known spectral templates to the measured LRS spectra. We use the Infrared Telescope Facility (IRTF) and Pickles 1998 (Cat. J/PASP/110/863) templates for the SED fitting. The SpeX instrument installed on the IRTF observed stars using a medium-resolution spectrograph (R=2000). The template library contains spectra for 210 cool stars (F to M type) with wavelength coverage from 0.8 to 2.5μm (Cushing 2005ApJ...623.1115C; Rayner 2009ApJS..185..289R). The Pickles library is a synthetic spectral library that combines spectral data from various observations to achieve wavelength coverage from the UV (0.115μm) to the near-infrared (2.5μm). It contains 131 spectral templates for all star types (i.e., O to M type) with a uniform sampling interval of 5Å. (6 data files).

Surfaces of Europa, Ganymede, and Callisto: an investigation using Voyager IRIS thermal infrared spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, J.R.

1987-01-01

In 1979, the IRIS infrared spectrometers on the two Voyager spacecraft obtained over 1000 disk-resolved thermal emission spectra of Europa, Ganymede, and Callisto, Jupiter's three large icy satellites. This dissertation describes the first detailed analysis of this data set. Ganymede and Callisto subsolar temperatures are 10 and 5/sup 0/K, respectively, below equilibrium values. Equatorial nighttime temperatures are between 100 and 75/sup 0/K, Callisto and Europa being colder than Ganymede. The diurnal temperature profiles can be matched by 2-layer surfaces that are also consistent with the eclipse cooling observed from earth, though previous eclipse models underestimated thermal inertias by about 50%.more » Substrate thermal inertias in the 2-layer models are a factor of several lower than for solid ice. These are cold spots on Ganymede and Callisto that are not high-albedo regions, which may indicate large thermal inertia anomalies.« less

Downwelling Far-Infrared Emission Spectra Measured By First at Cerro Toco, Chile and Table Mountain, California

NASA Astrophysics Data System (ADS)

Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

2014-12-01

The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Fourier transform spectrometer developed to measure the important far-infrared spectrum between 100 and 650 cm-1. Presented here are measurements made by FIRST during two successful deployments in a ground-based configuration to measure downwelling longwave radiation at Earth's surface. The initial deployment was to Cerro Toco, Chile, where FIRST operated from August to October, 2009 as part of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) campaign. After recalibration, FIRST was deployed to the Table Mountain Facility from September through October, 2012. Spectra observed at each location are substantially different, due in large part to the order of magnitude difference in integrated precipitable water vapor (0.3 cm at Table Mountain, 0.03 cm at Cerro Toco). Dry days for both campaigns are chosen for analysis - 09/24/2009 and 10/19/2012. Also available during both deployments are coincident radiosonde temperature and water vapor vertical profiles which are used as inputs a line-by-line radiative transfer program. Comparisons between measured and modeled spectra are presented over the 200 to 800 cm-1 range. An extensive error analysis of both the measured and modeled spectra is presented. In general, the differences between the measured and modeled spectra are within their combined uncertainties.

Phase controlled homodyne infrared near-field microscopy and spectroscopy reveal inhomogeneity within and among individual boron nitride nanotubes.

PubMed

Xu, Xiaoji G; Tanur, Adrienne E; Walker, Gilbert C

2013-04-25

We propose a practical method to obtain near-field infrared absorption spectra in apertureless near-field scanning optical microscopy (aNSOM) through homodyne detection with a specific choice of reference phase. The underlying mechanism of the method is illustrated by theoretical and numeric models to show its ability to obtain absorptive rather than dispersive profiles in near-field infrared vibrational microscopy. The proposed near-field nanospectroscopic method is applied to obtain infrared spectra from regions of individual multiwall boron nitride nanotubes (BNNTs) in spatial regions smaller than the diffraction limit of the light source. The spectra suggest variations in interwall spacing within the individual tubes probed.

Infrared spectra of SF6-.HCOOH.Arn (n=0-2): Infrared triggered reaction and Ar-induced reactive inhibition

NASA Astrophysics Data System (ADS)

Schneider, Holger; Takahashi, Kaito; Skodje, Rex T.; Weber, J. Mathias

2009-05-01

We present the infrared spectra of SF6-ṡHCOOHṡArm (m =0-2) complexes. We find that the binding motif involves a single hydrogen bond between the SF6- anion and the OH group of the formic acid, with the CH group weakly tethered to a neighboring F atom. Similar to the case of hydrated SF6-, the SF bond involved in the (OH-F) bond is significantly stretched and weakened by the attachment of the HCOOH ligand. The bare complex undergoes reaction upon infrared absorption in the CH/OH stretching region of the formic acid moiety, leading predominantly to the formation of SF4-+2HF+CO2. The reaction can be inhibited by attachment of two Ar atoms. We discuss a likely reaction mechanism in the framework of ab initio calculations, suggesting that reaction proceeds via tunneling through the potential barrier.

Spectral Irradiance Calibration in the Infrared. Part 7; New Composite Spectra, Comparison with Model Atmospheres, and Far-Infrared Extrapolations

NASA Technical Reports Server (NTRS)

Cohen, Martin; Witteborn, Fred C.; Carbon, Duane F.; Davies, John K.; Wooden, Diane H.; Bregman, Jesse D.

1996-01-01

We present five new absolutely calibrated continuous stellar spectra constructed as far as possible from spectral fragments observed from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer. These stars-alpha Boo, gamma Dra, alpha Cet, gamma Cru, and mu UMa-augment our six, published, absolutely calibrated spectra of K and early-M giants. All spectra have a common calibration pedigree. A revised composite for alpha Boo has been constructed from higher quality spectral fragments than our previously published one. The spectrum of gamma Dra was created in direct response to the needs of instruments aboard the Infrared Space Observatory (ISO); this star's location near the north ecliptic pole renders it highly visible throughout the mission. We compare all our low-resolution composite spectra with Kurucz model atmospheres and find good agreement in shape, with the obvious exception of the SiO fundamental, still lacking in current grids of model atmospheres. The CO fundamental seems slightly too deep in these models, but this could reflect our use of generic models with solar metal abundances rather than models specific to the metallicities of the individual stars. Angular diameters derived from these spectra and models are in excellent agreement with the best observed diameters. The ratio of our adopted Sirius and Vega models is vindicated by spectral observations. We compare IRAS fluxes predicted from our cool stellar spectra with those observed and conclude that, at 12 and 25 microns, flux densities measured by IRAS should be revised downwards by about 4.1% and 5.7%, respectively, for consistency with our absolute calibration. We have provided extrapolated continuum versions of these spectra to 300 microns, in direct support of ISO (PHT and LWS instruments). These spectra are consistent with IRAS flux densities at 60 and 100 microns.

Infrared Spectroscopy of Explosives Residues: Measurement Techniques and Spectral Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Mark C.; Bernacki, Bruce E.

2015-03-11

Infrared laser spectroscopy of explosives is a promising technique for standoff and non-contact detection applications. However, the interpretation of spectra obtained in typical standoff measurement configurations presents numerous challenges. Understanding the variability in observed spectra from explosives residues and particles is crucial for design and implementation of detection algorithms with high detection confidence and low false alarm probability. We discuss a series of infrared spectroscopic techniques applied toward measuring and interpreting the reflectance spectra obtained from explosives particles and residues. These techniques utilize the high spectral radiance, broad tuning range, rapid wavelength tuning, high scan reproducibility, and low noise ofmore » an external cavity quantum cascade laser (ECQCL) system developed at Pacific Northwest National Laboratory. The ECQCL source permits measurements in configurations which would be either impractical or overly time-consuming with broadband, incoherent infrared sources, and enables a combination of rapid measurement speed and high detection sensitivity. The spectroscopic methods employed include standoff hyperspectral reflectance imaging, quantitative measurements of diffuse reflectance spectra, reflection-absorption infrared spectroscopy, microscopic imaging and spectroscopy, and nano-scale imaging and spectroscopy. Measurements of explosives particles and residues reveal important factors affecting observed reflectance spectra, including measurement geometry, substrate on which the explosives are deposited, and morphological effects such as particle shape, size, orientation, and crystal structure.« less

Combining near infrared spectra of feces and geostatistics to generate forage nutritional quality maps across landscapes

NASA Astrophysics Data System (ADS)

Jean, Pierre-Olivier; Bradley, Robert; Tremblay, Jean-Pierre

2015-04-01

An important asset for the management of wild ungulates is the ability to recognize the spatial distribution of forage quality across heterogeneous landscapes. To do so typically requires knowledge of which plant species are eaten, in what abundance they are eaten, and what their nutritional quality might be. Acquiring such data may be, however, difficult and time consuming. Here, we are proposing a rapid and cost-effective forage quality monitoring tool that combines near infrared (NIR) spectra of fecal samples and easily obtained data on plant community composition. Our approach rests on the premise that NIR spectra of fecal samples collected within low population density exclosures reflect the optimal forage quality of a given landscape. Forage quality can thus be based on the Mahalanobis distance of fecal spectral scans across the landscape relative to fecal spectral scans inside exclosures (referred to as DISTEX). The Gi* spatial autocorrelation statistic can then be applied among neighbouring DISTEX values to detect and map 'hot-spots' and 'cold-spots' of nutritional quality over the landscape. We tested our approach in a heterogeneous boreal landscape on Anticosti Island (Qu

Inference of Surface Parameters from Near-Infrared Spectra of Crystalline H2O Ice with Neural Learning

NASA Astrophysics Data System (ADS)

Zhang, Lili; Merényi, Erzsébet; Grundy, William M.; Young, Eliot F.

2010-07-01

The near-infrared spectra of icy volatiles collected from planetary surfaces can be used to infer surface parameters, which in turn may depend on the recent geologic history. The high dimensionality and complexity of the spectral data, the subtle differences between the spectra, and the highly nonlinear interplay between surface parameters make it often difficult to accurately derive these surface parameters. We use a neural machine, with a Self-Organizing Map (SOM) as its hidden layer, to infer the latent physical parameters, temperature and grain size from near-infrared spectra of crystalline H2O ice. The output layer of the SOM-hybrid machine is customarily trained with only the output from the SOM winner. We show that this scheme prevents simultaneous achievement of high prediction accuracies for both parameters. We propose an innovative neural architecture we call Conjoined Twins that allows multiple (k) SOM winners to participate in the training of the output layer and in which the customization of k can be limited automatically to a small range. With this novel machine we achieve scientifically useful accuracies, 83.0 ± 2.7% and 100.0 ± 0.0%, for temperature and grain size, respectively, from simulated noiseless spectra. We also show that the performance of the neural model is robust under various noisy conditions. A primary application of this prediction capability is planned for spectra returned from the Pluto-Charon system by New Horizons.

Correlations Between Textures and Infrared Spectra of the Martian Surface in Valles Marineris

NASA Astrophysics Data System (ADS)

Ralston, S. J.; Wray, J. J.

2013-12-01

RALSTON, S. J., School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, sralston3@gatech.edu, WRAY, James, School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, jwray@eas.gatech.edu In the past few decades, a wealth of information has become available on the appearance and composition of the Martian surface. While some previous research has examined possible correlations between certain surface features and mineralogy (such as the hypothesized connection between Recurring Slope Lineae and perchlorate salts), little has yet been done to determine possible correlations between mineralogy and texture in less extraordinary circumstances. In this project, one hundred images taken from across the Valles Marineris region were examined both in infrared (obtained from the CRISM instrument aboard the Mars Reconnaissance Orbiter) and in visible-light images from the HiRISE camera. Spectra were obtained from regions of interest, focusing mainly on the identification of monohydrated and polyhydrated sulfates. Other materials were included in the imaging, including phyllosilicate clays, gypsum, and jarosite, although those materials proved less abundant than the sulfates. The areas from which the spectra were taken were then examined in visible-light wavelengths using HiRISE images to determine textural qualities. The focus of this research was on two particular textures, a 'reticulated' texture and a 'stepped texture,' hypothesized to correlate to monohydrated and polyhydrated sulfates, respectively. Results showed that over 55% of areas containing monohydrated sulfates also contained reticulate texture, whereas areas that contained other materials, such as polyhydrated sulfates and clays, had only a 2-8% correlation with reticulate texture. The stepped texture was shown to have no significant correlation to any one material, although other texture/mineral pairs did

Measurements of constituents of interest in the photochemistry of the ozone layer using infrared techniques

NASA Technical Reports Server (NTRS)

Murcray, D. G.; Williams, J. W.; Barker, D. B.; Goldman, A.; Bradford, C.; Cook, G.

1978-01-01

Infrared solar spectra and infrared atmospheric emission spectra were obtained from the ground, from aircraft and from balloons. The initial detection of most stratospheric molecules was achieved by the solar spectral technique because better resolution helps remove interference from other molecules. Because the sun is an intense source of radiation, the resolution which can be obtained with good signal-to-noise, is greater than with atmospheric emission spectroscopy. Data are generally taken using a method that enhances the number of molecules in the optical path i.e. at large solar zenith angles for solar spectra and at low elevation angles for atmospheric emission spectra. The search for molecules which are predicted to be present but which, the detection of a molecule known to be present from other measurement techniques but observed for the first time in infrared solar spectra, and some further data on the variability of HNO3 are discussed.

Infrared spectra of magnetoresistive ferromagnets in magnetic fields

NASA Astrophysics Data System (ADS)

Telegin, A. V.; Bessonova, V. A.; Sukhorukov, Yu. P.

2018-05-01

The influence of a magnetic field on reflection and transmission spectra of ferromagnetic manganites possessed the colossal magnetoresistance effect has been in the infrared range studied. It was shown that observed magnetotransmission and magnetoreflection of unpolarized light are an optical response to the colossal magnetoresistance in optimally doped manganites. Compared to crystals and multilayers the effects are the most pronounced and reach the magnitude of up to few tens of percent in single-layer thin films near the Curie temperature. A new low-temperature mechanism of magnetotransmission connected with the tunnel magnetoresistance was revealed far below the Curie point in Ba-doped manganite films with a variant structure. The observed magneto-optical effects in manganites can be described in the framework of the magnetorefractive effect theory. The observed effects are one or two orders of magnitude greater than the conventional IR magnetooptical phenomena in manganites. Being quite large, magnetoreflection and magnetotransmission effects in manganites structures could be successfully used in optoelectronics.

VizieR Online Data Catalog: Optical to NIR spectra of nova V2676 Oph 2012 (Raj+, 2017)

NASA Astrophysics Data System (ADS)

Raj, A.; Das, R. K.; Walter, F. M.

2017-09-01

Near-infrared observations were obtained using the 1.2m telescope of Mt.Abu Infrared Observatory from 2012 March 29 to June 18 and the SMARTS/CTIO 1.3m telescope. The SMARTS photometry is available on the SMARTS atlas (Walter+, 2012PASP..124.1057W). Optical spectra were obtained with the Asiago 1.22m telescope + B&C spectrograph. Further low-dispersion spectra and photometry were obtained using the SMARTS 1.5m facilities. We obtained 19 spectra on an irregular cadence and with various sky conditions from 2012 April 5 through 2012 June 24. The target was observed using the COSMOS long slit spectrograph at CTIO on 2015 May 8, some three years after the outburst. (3 data files).

Water vapor in Titan's stratosphere from Cassini CIRS far-infrared spectra

NASA Astrophysics Data System (ADS)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bézard, B.; de Kok, R.; Lellouch, E.; Irwin, P. G. J.; Flasar, F. M.; Bampasidis, G.

2012-08-01

Here we report the measurement of water vapor in Titan's stratosphere using the Cassini Composite Infrared Spectrometer (CIRS, Flasar, F.M. et al. [2004]. Space Sci. Rev. 115, 169-297). CIRS senses water emissions in the far infrared spectral region near 50 μm, which we have modeled using two independent radiative transfer codes (NEMESIS (Irwin, P.G.J. et al. [2008]. J. Quant. Spectrosc. Radiat. Trans. 109, 1136-1150) and ART (Coustenis, A. et al. [2007]. Icarus 189, 35-62; Coustenis, A. et al. [2010]. Icarus 207, 461-476). From the analysis of nadir spectra we have derived a mixing ratio of 0.14 ± 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 ± 1.3 × 1014 molecules/cm2. In the latitude range 80°S to 30°N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 ± 0.04 ppb at an altitude of 115 km and 0.45 ± 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models (e.g. Lara, L.M., Lellouch, F., Lopez-Moreno, J.J., Rodrigo, R. [1996]. J. Geophys. Res. 101(23), 261; Wilson, E.H., Atreya, S.K. [2004]. J. Geophys. Res. 109, E6; Hörst, S.M., Vuitton, V., Yelle, R.V. [2008]. J. Geophys. Res., 113, E10). We have also fitted our data using scaling factors of ˜0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan's lower stratosphere.

Mid-infrared spectra of cometary dust: the evasion of its silicate mineralogy

NASA Astrophysics Data System (ADS)

Kimura, H.; Chigai, T.; Yamamoto, T.

2008-04-01

Infrared spectra of dust in cometary comae provide a way to identify its silicate constituents, and this is crucial for correctly understanding the condition under which our planetary system is formed. Recent studies assign a newly detected peak at a wavelength of 9.3 μm to pyroxenes and regard them as the most abundant silicate minerals in comets. Here we dispense with this pyroxene hypothesis to numerically reproduce the infrared features of cometary dust in the framework of our interstellar dust models. Presolar interstellar dust in a comet is modeled as fluffy aggregates consisting of submicrometer-sized organic grains with an amorphous-silicate core that undergoes nonthermal crystallization in a coma. We assert that forsterite (Mg2SiO4) is the carrier of all the observed features, including the 9.3 μm peak and that the major phase of iron is sulfides rather than iron-rich silicates.

Meeting the Cool Neighbors. XII. An Optically Anchored Analysis of the Near-infrared Spectra of L Dwarfs

NASA Astrophysics Data System (ADS)

Cruz, Kelle L.; Núñez, Alejandro; Burgasser, Adam J.; Abrahams, Ellianna; Rice, Emily L.; Reid, I. Neill; Looper, Dagny

2018-01-01

Discrepancies between competing optical and near-infrared (NIR) spectral typing systems for L dwarfs have motivated us to search for a classification scheme that ties the optical and NIR schemes together, and addresses complexities in the spectral morphology. We use new and extant optical and NIR spectra to compile a sample of 171 L dwarfs, including 27 low-gravity β and γ objects, with spectral coverage from 0.6–2.4 μm. We present 155 new low-resolution NIR spectra and 19 new optical spectra. We utilize a method for analyzing NIR spectra that partially removes the broad-band spectral slope and reveals similarities in the absorption features between objects of the same optical spectral type. Using the optical spectra as an anchor, we generate near-infrared spectral average templates for L0–L8, L0–L4γ, and L0–L1β type dwarfs. These templates reveal that NIR spectral morphologies are correlated with the optical types. They also show the range of spectral morphologies spanned by each spectral type. We compare low-gravity and field-gravity templates to provide recommendations on the minimum required observations for credibly classifying low-gravity spectra using low-resolution NIR data. We use the templates to evaluate the existing NIR spectral standards and propose new ones where appropriate. Finally, we build on the work of Kirkpatrick et al. to provide a spectral typing method that is tied to the optical and can be used when only H or K band data are available. The methods we present here provide resolutions to several long-standing issues with classifying L dwarf spectra and could also be the foundation for a spectral classification scheme for cloudy exoplanets.

Predicting ambient aerosol thermal-optical reflectance (TOR) measurements from infrared spectra: organic carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2015-03-01

Organic carbon (OC) can constitute 50% or more of the mass of atmospheric particulate matter. Typically, organic carbon is measured from a quartz fiber filter that has been exposed to a volume of ambient air and analyzed using thermal methods such as thermal-optical reflectance (TOR). Here, methods are presented that show the feasibility of using Fourier transform infrared (FT-IR) absorbance spectra from polytetrafluoroethylene (PTFE or Teflon) filters to accurately predict TOR OC. This work marks an initial step in proposing a method that can reduce the operating costs of large air quality monitoring networks with an inexpensive, non-destructive analysis technique using routinely collected PTFE filter samples which, in addition to OC concentrations, can concurrently provide information regarding the composition of organic aerosol. This feasibility study suggests that the minimum detection limit and errors (or uncertainty) of FT-IR predictions are on par with TOR OC such that evaluation of long-term trends and epidemiological studies would not be significantly impacted. To develop and test the method, FT-IR absorbance spectra are obtained from 794 samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least-squares regression is used to calibrate sample FT-IR absorbance spectra to TOR OC. The FTIR spectra are divided into calibration and test sets by sampling site and date. The calibration produces precise and accurate TOR OC predictions of the test set samples by FT-IR as indicated by high coefficient of variation (R2; 0.96), low bias (0.02 μg m-3, the nominal IMPROVE sample volume is 32.8 m3), low error (0.08 μg m-3) and low normalized error (11%). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision to collocated TOR measurements. FT-IR spectra are also

Theoretical Study of Infrared and Raman Spectra of Hydrated Magnesium Sulfate Salts

NASA Technical Reports Server (NTRS)

Chaban, Galina M.; Huo, Winifred M.; Lee, Timothy J.; Kwak, Dochan (Technical Monitor)

2002-01-01

Harmonic and anharmonic vibrational frequencies, as well as infrared and Raman intensities, are calculated for MgSO4.nH20 (n=1-3). Electronic structure theory at the second order Moller-Plesset perturbation theory (MP2) level with a triple-zeta + polarization (TZP) basis set is used to determine the geometry, properties, and vibrational spectra of pure and hydrated MgSO4 salts. The direct vibrational self-consistent field (VSCF) method and its correlation corrected (CC-VSCF) extension are used to determine anharmonic corrections to vibrational frequencies and intensities for the pure MgSO4 and its complex with one water molecule. Very significant differences are found between vibrational of water molecules in complexes with MgSO4 and pure water. Some of the O-H stretching frequencies are shifted to the red very significantly (by up to 1500-2000/cm) upon complexation with magnesium sulfate. They should be observed between 1700 and 3000/cm in a region very different from the corresponding O-H stretch frequency region of pure water (3700-3800/cm). In addition, the SO2 stretching vibrations are found at lower frequency regions than the water vibrations. They can serve as unique identifiers for the presence of sulfate salts. The predicted infrared and Raman spectra should be of valuable help in the design of future missions and analysis of observed data from the ice surface of Jupiter's moon Europa that possibly contains hydrated MgSO4 salts.

Cis- and trans-perfluorodecalin: Infrared spectra, radiative efficiency and global warming potential

NASA Astrophysics Data System (ADS)

Le Bris, Karine; DeZeeuw, Jasmine; Godin, Paul J.; Strong, Kimberly

2017-12-01

Perfluorodecalin (PFD) is a molecule used in various medical applications for its capacity to dissolve gases. This potent greenhouse gas was detected for the first time in the atmosphere in 2005. We present infrared absorption cross-section spectra of a pure vapour of cis- and trans-perfluorodecalin at a resolution of 0.1 cm-1. Measurements were performed in the 560-3000 cm-1 spectral range using Fourier transform spectroscopy. The spectra have been compared with previous experimental data and theoretical calculations by density functional theory. The new experimental absorption cross-sections have been used to calculate a lifetime-corrected radiative efficiency at 300 K of 0.62 W m-2 ppb-1 and 0.57 W.m-2.ppb-1 for the cis and trans isomers respectively. This leads to a 100-year time horizon global warming potential of 8030 for cis-PFD and 7440 for trans-PFD.

Using late-time optical and near-infrared spectra to constrain Type Ia supernova explosion properties

NASA Astrophysics Data System (ADS)

Maguire, K.; Sim, S. A.; Shingles, L.; Spyromilio, J.; Jerkstrand, A.; Sullivan, M.; Chen, T.-W.; Cartier, R.; Dimitriadis, G.; Frohmaier, C.; Galbany, L.; Gutiérrez, C. P.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Rudy, R.; Sollerman, J.

2018-03-01

The late-time spectra of Type Ia supernovae (SNe Ia) are powerful probes of the underlying physics of their explosions. We investigate the late-time optical and near-infrared spectra of seven SNe Ia obtained at the VLT with XShooter at >200 d after explosion. At these epochs, the inner Fe-rich ejecta can be studied. We use a line-fitting analysis to determine the relative line fluxes, velocity shifts, and line widths of prominent features contributing to the spectra ([Fe II], [Ni II], and [Co III]). By focussing on [Fe II] and [Ni II] emission lines in the ˜7000-7500 Å region of the spectrum, we find that the ratio of stable [Ni II] to mainly radioactively-produced [Fe II] for most SNe Ia in the sample is consistent with Chandrasekhar-mass delayed-detonation explosion models, as well as sub-Chandrasekhar mass explosions that have metallicity values above solar. The mean measured Ni/Fe abundance of our sample is consistent with the solar value. The more highly ionised [Co III] emission lines are found to be more centrally located in the ejecta and have broader lines than the [Fe II] and [Ni II] features. Our analysis also strengthens previous results that SNe Ia with higher Si II velocities at maximum light preferentially display blueshifted [Fe II] 7155 Å lines at late times. Our combined results lead us to speculate that the majority of normal SN Ia explosions produce ejecta distributions that deviate significantly from spherical symmetry.

DERIVING METALLICITIES FROM THE INTEGRATED SPECTRA OF EXTRAGALACTIC GLOBULAR CLUSTERS USING THE NEAR-INFRARED CALCIUM TRIPLET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, Caroline; Forbes, Duncan A.; Proctor, Robert N.

2010-04-15

The Ca II triplet (CaT) feature in the near-infrared has been employed as a metallicity indicator for individual stars as well as integrated light of Galactic globular clusters (GCs) and galaxies with varying degrees of success, and sometimes puzzling results. Using the DEIMOS multi-object spectrograph on Keck we obtain a sample of 144 integrated light spectra of GCs around the brightest group galaxy NGC 1407 to test whether the CaT index can be used as a metallicity indicator for extragalactic GCs. Different sets of single stellar population models make different predictions for the behavior of the CaT as a functionmore » of metallicity. In this work, the metallicities of the GCs around NGC 1407 are obtained from CaT index values using an empirical conversion. The measured CaT/metallicity distributions show unexpected features, the most remarkable being that the brightest red and blue GCs have similar CaT values despite their large difference in mean color. Suggested explanations for this behavior in the NGC 1407 GC system are (1) the CaT may be affected by a population of hot blue stars, (2) the CaT may saturate earlier than predicted by the models, and/or (3) color may not trace metallicity linearly. Until these possibilities are understood, the use of the CaT as a metallicity indicator for the integrated spectra of extragalactic GCs will remain problematic.« less

Infrared Photodissociation Spectroscopy of Metal Ion -WATER Complexes

NASA Astrophysics Data System (ADS)

Bandyopadhyay, B.; Carnegie, P. D.; Duncan, M. A.

2011-06-01

Metal ion-water complexes are produced in a supersonic expansion cluster source via laser vaporization technique. Infrared photodissociation spectroscopy has been performed in the O-H stretch region. DFT calculations have also been carried out to obtain the structures and vibrational frequencies. Infrared spectra show partially resolved rotational structures which will be analyzed.

Water vapor on Titan: the stratospheric vertical profile from Cassini/CIRS infrared spectra

NASA Astrophysics Data System (ADS)

Cottini, V.; Jennings, D. E.; Nixon, C. A.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Achterberg, R. K.; Teanby, N. A.; de Kok, R.; Irwin, P. G. J.; Bézard, B.; Lellouch, E.; Flasar, F. M.; Bampasidis, G.

2012-04-01

Water vapor in Titan’s middle atmosphere has previously been detected only by disk-average observations from the Infrared Space Observatory (Coustenis et al., 1998). We report here the successful detection of stratospheric water vapor using the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al., 2004) following an earlier null result (de Kok et al., 2007a). CIRS senses water emissions in the far-infrared spectral region near 50 microns, which we have modeled using two independent radiative transfer and inversion codes (NEMESIS, Irwin et al 2008 and ART, Coustenis et al., 2010). From the analysis of nadir spectra we have derived a mixing ratio of (0.14 ± 0.05) ppb at 100 km, corresponding to a column abundance of approximately (3.7 ± 1.3) × 10^14 mol/cm2. Using limb observations, we obtained mixing ratios of (0.13 ± 0.04) ppb at 125 km and (0.45 ± 0.15) ppb at 225 km of altitude, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. In the latitude range (80˚S - 30˚N) we see no evidence for latitudinal variations in these abundances within the error bars. References: Coustenis, A.; Salama, A.; Lellouch, E.; Encrenaz, Th.; Bjoraker, G. L.; Samuelson, R. E.; de Graauw, Th.; Feuchtgruber, H.; Kessler, M. F., 1998. Evidence for water vapor in Titan's atmosphere from ISO/SWS data. Astronomy and Astrophysics, v.336, p.L85-L89 Coustenis, A.; Jennings, D. E.; Nixon, C. A.; Achterberg, R. K.; Lavvas, P.; Vinatier, S.; Teanby, N. A.; Bjoraker, G. L.; Carlson, R. C.; Piani, L.; Bampasidis, G.; Flasar, F. M.; Romani, P. N., 2010. Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission. Icarus, Volume 207, Issue 1, p. 461-476. de Kok, R.; Irwin, P. G. J.; Teanby, N. A.; Lellouch, E.; Bézard, B.; Vinatier, S.; Nixon, C. A.; Fletcher, L.; Howett, C.; Calcutt, S. B.; Bowles, N. E.; Flasar, F. M.; Taylor, F. W. , 2007a. Oxygen compounds in Titan's stratosphere as observed by

Near infrared cavity enhanced absorption spectra of atmospherically relevant ether-1, 4-Dioxane.

PubMed

Chandran, Satheesh; Varma, Ravi

2016-01-15

1, 4-Dioxane (DX) is a commonly found ether in industrially polluted atmosphere. The near infrared absorption spectra of this compound has been recorded in the region 5900-8230 cm(-1) with a resolution of 0.08 cm(-1) using a novel Fourier transform incoherent broadband cavity-enhanced absorption spectrometer (FT-IBBCEAS). All recorded spectra were found to contain regions that are only weakly perturbed. The possible combinations of fundamental modes and their overtone bands corresponding to selected regions in the measured spectra are tabulated. Two interesting spectral regions were identified as 5900-6400 cm(-1) and 8100-8230 cm(-1). No significant spectral interference due to presence of water vapor was observed suggesting the suitability of these spectral signatures for spectroscopic in situ detection of DX. The technique employed here is much more sensitive than standard Fourier transform spectrometer measurements on account of long effective path length achieved. Hence significant enhancement of weaker absorption lines above the noise level was observed as demonstrated by comparison with an available measurement from database. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of a thioether lubricant by infrared Fourier microemission spectrophotometry

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Morales, W.; Lauer, J. L.

1986-01-01

An infrared Fourier microemission spectrophotometer is used to obtain spectra (wavenumber range, 630 to 1230 0.1 cm) from microgram quantities of thioether lubricant samples deposited on aluminum foil. Infrared bands in the spectra are reproducible and could be identified as originating from aromatic species (1,3-disubstituted benzenes). Spectra from all samples (neat and formulated, used and unused) are very similar. Additives (an acid and a phosphinate) present in low concentration (0.10 percent) in the formulated fluid are not detected. This instrument appears to be a viable tool in helping to identify lubricant components separated by liquid chromatography.

Does Nonlinear Modeling Play a Role in Plasmid Bioprocess Monitoring Using Fourier Transform Infrared Spectra?

PubMed

Lopes, Marta B; Calado, Cecília R C; Figueiredo, Mário A T; Bioucas-Dias, José M

2017-06-01

The monitoring of biopharmaceutical products using Fourier transform infrared (FT-IR) spectroscopy relies on calibration techniques involving the acquisition of spectra of bioprocess samples along the process. The most commonly used method for that purpose is partial least squares (PLS) regression, under the assumption that a linear model is valid. Despite being successful in the presence of small nonlinearities, linear methods may fail in the presence of strong nonlinearities. This paper studies the potential usefulness of nonlinear regression methods for predicting, from in situ near-infrared (NIR) and mid-infrared (MIR) spectra acquired in high-throughput mode, biomass and plasmid concentrations in Escherichia coli DH5-α cultures producing the plasmid model pVAX-LacZ. The linear methods PLS and ridge regression (RR) are compared with their kernel (nonlinear) versions, kPLS and kRR, as well as with the (also nonlinear) relevance vector machine (RVM) and Gaussian process regression (GPR). For the systems studied, RR provided better predictive performances compared to the remaining methods. Moreover, the results point to further investigation based on larger data sets whenever differences in predictive accuracy between a linear method and its kernelized version could not be found. The use of nonlinear methods, however, shall be judged regarding the additional computational cost required to tune their additional parameters, especially when the less computationally demanding linear methods herein studied are able to successfully monitor the variables under study.

Mid-Infrared Vibrational Spectra of Discrete Acetone-Ligated Cerium Hydroxide Cations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groenewold, G. S.; Gianotto, Anita K.; Cossel, Kevin C.

2007-02-15

Cerium (III) hydroxy reactive sites are responsible for several important heterogeneous catalysis processes, and understanding the reaction chemistry of substrate molecules like CO, H2O, and CH3OH as they occur in heterogeneous media is a challenging task. We report here the first infrared spectra of model gas-phase cerium complexes and use the results as a benchmark to assist evaluation of the accuracy of ab initio calculations. Complexes containing [CeOH]2+ ligated by three- and four-acetone molecules were generated by electrospray ionization and characterized using wavelength-selective infrared multiple photon dissociation (IRMPD). The C=O stretching frequency for the [CeOH(acetone)4]2+ species appeared at 1650 cm-1more » and was red-shifted by 90 cm-1 compared to unligated acetone. The magnitude of this shift for the carbonyl frequency was even greater for the [CeOH(acetone)3]2+ complex: the IRMPD peak consisted of two dissociation channels, an initial elimination of acetone at 1635 cm-1, and elimination of acetone accompanied by a serial charge separation producing [CeO(acetone)]+ at 1599 cm-1, with the overall frequency centered at 1616 cm-1. The increasing red shift observed as the number of acetone ligands decreases from four to three is consistent with transfer of more electron density per ligand in the less coordinated complexes. The lower frequency measured for the elimination/charge separation process is likely due to anharmonicity resulting from population of higher vibrational states. The C-C stretching frequency in the complexes is also influenced by coordination to the metal: it is blue-shifted compared to bare acetone, indicating a slight strengthening of the C-C bond in the complex, with the intensity of the absorption decreasing with decreasing ligation. Density functional theory (DFT) calculations using three different functionals (LDA, B3LYP, and PBE0) are used to predict the infrared spectra of the complexes. Calculated frequencies for the

AKARI observations of brown dwarfs. IV. Effect of elemental abundances on near-infrared spectra between 1.0 and 5.0 μm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorahana, S.; Yamamura, I.

2014-09-20

The detection of the CO{sub 2} absorption band at 4.2 μm in brown dwarf spectra by AKARI has made it possible to discuss CO{sub 2} molecular abundance in brown dwarf atmospheres. In our previous studies, we found an excess in the 4.2 μm CO{sub 2} absorption band of three brown dwarf spectra, and suggested that these deviations were caused by high C and O elemental abundances in their atmospheres. To validate this hypothesis, we have constructed a set of models of brown dwarf atmospheres with various elemental abundance patterns, and we investigate the variations of the molecular composition and themore » thermal structure, and how they affect the near-infrared spectra between 1.0 and 5.0 μm. The 4.2 μm CO{sub 2} absorption band in some late-L and T dwarfs taken by AKARI is stronger or weaker than predicted by corresponding models with solar abundance. By comparing the CO{sub 2} band in the model spectra to the observed near-infrared spectra, we confirm possible elemental abundance variations among brown dwarfs. We find that the band strength is especially sensitive to O abundance, but C is also needed to reproduce the entire near-infrared spectra. This result indicates that both the C and O abundances should increase and decrease simultaneously for brown dwarfs. We find that a weaker CO{sub 2} absorption band in a spectrum can also be explained by a model with lower 'C and O' abundances.« less

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE (background) remove sections of the transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. Additional workers (foreground) prepare the Delta payload attach fitting, from which SIRTF was demated, for further use. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

NASA Image and Video Library

2003-05-02

KENNEDY SPACE CENTER, FLA. - Workers in NASA Spacecraft Hangar AE (background) remove sections of the transportation canister from around the Space Infrared Telescope Facility (SIRTF), which has been returned to the hangar from the launch pad. Additional workers (foreground) prepare the Delta payload attach fitting, from which SIRTF was demated, for further use. SIRTF will remain in the clean room until it returns to the pad in early August. 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.

Thermal-infrared spectral observations of geologic materials in emission

NASA Technical Reports Server (NTRS)

Christensen, Philip R.; Luth, Sharon J.

1987-01-01

The thermal-infrared spectra of geologic materials in emission were studied using the prototype Thermal Emission Spectrometer (TES). A variety of of processes and surface modifications that may influence or alter the spectra of primary rock materials were studied. It was confirmed that thermal emission spectra contain the same absorption features as those observed in transmission and reflection spectra. It was confirmed that the TES instrument can be used to obtain relevant spectra for analysis of rock and mineral composition.

Profiles of stratospheric chlorine nitrate (ClONO2) from atmospheric trace molecule spectroscopy/ATLAS 1 infrared solar occultation spectra

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Mahieu, E.; Goldman, A.; Ko, M. K. W.; Rodriguez, J. M.; Sze, N. D.

1994-01-01

Stratospheric volume mixing ratio profiles of chlorine nitrate (ClONO2) have been retrieved from 0.01/cm resolution infrared solar occultation spectra recorded at latitudes between 14 deg N and 54 deg S by the atmospheric trace molecule spectroscopy Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS) 1 shuttle mission (March 24 to April 2, 1992). The results were obtained from nonlinear least squares fittings of the ClONO2 nu(sub 4) band Q branch at 780.21/cm with improved spectroscopic parameters generated on the basis of recent laboratory work. The individual profiles, which have an accuracy of about +/- 20%, are compared with previous observations and model calculations.

Search prefilters to assist in library searching of infrared spectra of automotive clear coats.

PubMed

Lavine, Barry K; Fasasi, Ayuba; Mirjankar, Nikhil; White, Collin; Sandercock, Mark

2015-01-01

Clear coat searches of the infrared (IR) spectral library of the paint data query (PDQ) forensic database often generate an unusable number of hits that span multiple manufacturers, assembly plants, and years. To improve the accuracy of the hit list, pattern recognition methods have been used to develop search prefilters (i.e., principal component models) that differentiate between similar but non-identical IR spectra of clear coats on the basis of manufacturer (e.g., General Motors, Ford, Chrysler) or assembly plant. A two step procedure to develop these search prefilters was employed. First, the discrete wavelet transform was used to decompose each IR spectrum into wavelet coefficients to enhance subtle but significant features in the spectral data. Second, a genetic algorithm for IR spectral pattern recognition was employed to identify wavelet coefficients characteristic of the manufacturer or assembly plant of the vehicle. Even in challenging trials where the paint samples evaluated were all from the same manufacturer (General Motors) within a limited production year range (2000-2006), the respective assembly plant of the vehicle was correctly identified. Search prefilters to identify assembly plants were successfully validated using 10 blind samples provided by the Royal Canadian Mounted Police (RCMP) as part of a study to populate PDQ to current production years, whereas the search prefilter to discriminate among automobile manufacturers was successfully validated using IR spectra obtained directly from the PDQ database. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of the Hydration State on the Mid-Infrared Spectra of Urea and Creatinine in Relation to Urine Analyses

PubMed Central

Oliver, Katherine V.; Maréchal, Amandine

2016-01-01

When analyzing solutes by Fourier transform infrared (FT-IR) spectroscopy in attenuated total reflection (ATR) mode, drying of samples onto the ATR crystal surface can greatly increase solute band intensities and, therefore, aid detection of minor components. However, analysis of such spectra is complicated by the existence of alternative partial hydration states of some substances that can significantly alter their infrared signatures. This is illustrated here with urea, which is a dominant component of urine. The effects of hydration state on its infrared spectrum were investigated both by incubation in atmospheres of fixed relative humidities and by recording serial spectra during the drying process. Significant changes of absorption band positions and shapes were observed. Decomposition of the CN antisymmetric stretching (νas) band in all states was possible with four components whose relative intensities varied with hydration state. These correspond to the solution (1468 cm–1) and dry (1464 cm–1) states and two intermediate (1454 cm–1 and 1443 cm–1) forms that arise from specific urea–water and/or urea–urea interactions. Such intermediate forms of other compounds can also be formed, as demonstrated here with creatinine. Recognition of these states and their accommodation in analyses of materials such as dried urine allows more precise decomposition of spectra so that weaker bands of diagnostic interest can be more accurately defined. PMID:27170705

Effects of the Hydration State on the Mid-Infrared Spectra of Urea and Creatinine in Relation to Urine Analyses.

PubMed

Oliver, Katherine V; Maréchal, Amandine; Rich, Peter R

2016-06-01

When analyzing solutes by Fourier transform infrared (FT-IR) spectroscopy in attenuated total reflection (ATR) mode, drying of samples onto the ATR crystal surface can greatly increase solute band intensities and, therefore, aid detection of minor components. However, analysis of such spectra is complicated by the existence of alternative partial hydration states of some substances that can significantly alter their infrared signatures. This is illustrated here with urea, which is a dominant component of urine. The effects of hydration state on its infrared spectrum were investigated both by incubation in atmospheres of fixed relative humidities and by recording serial spectra during the drying process. Significant changes of absorption band positions and shapes were observed. Decomposition of the CN antisymmetric stretching (νas) band in all states was possible with four components whose relative intensities varied with hydration state. These correspond to the solution (1468 cm(-1)) and dry (1464 cm(-1)) states and two intermediate (1454 cm(-1) and 1443 cm(-1)) forms that arise from specific urea-water and/or urea-urea interactions. Such intermediate forms of other compounds can also be formed, as demonstrated here with creatinine. Recognition of these states and their accommodation in analyses of materials such as dried urine allows more precise decomposition of spectra so that weaker bands of diagnostic interest can be more accurately defined. © The Author(s) 2016.

Data-driven signal-resolving approaches of infrared spectra to explore the macroscopic and microscopic spatial distribution of organic and inorganic compounds in plant.

PubMed

Chen, Jian-bo; Sun, Su-qin; Zhou, Qun

2015-07-01

The nondestructive and label-free infrared (IR) spectroscopy is a direct tool to characterize the spatial distribution of organic and inorganic compounds in plant. Since plant samples are usually complex mixtures, signal-resolving methods are necessary to find the spectral features of compounds of interest in the signal-overlapped IR spectra. In this research, two approaches using existing data-driven signal-resolving methods are proposed to interpret the IR spectra of plant samples. If the number of spectra is small, "tri-step identification" can enhance the spectral resolution to separate and identify the overlapped bands. First, the envelope bands of the original spectrum are interpreted according to the spectra-structure correlations. Then the spectrum is differentiated to resolve the underlying peaks in each envelope band. Finally, two-dimensional correlation spectroscopy is used to enhance the spectral resolution further. For a large number of spectra, "tri-step decomposition" can resolve the spectra by multivariate methods to obtain the structural and semi-quantitative information about the chemical components. Principal component analysis is used first to explore the existing signal types without any prior knowledge. Then the spectra are decomposed by self-modeling curve resolution methods to estimate the spectra and contents of significant chemical components. At last, targeted methods such as partial least squares target can explore the content profiles of specific components sensitively. As an example, the macroscopic and microscopic distribution of eugenol and calcium oxalate in the bud of clove is studied.

Properties of Energy Spectra of Molecular Crystals Investigated by Nonlinear Theory

NASA Astrophysics Data System (ADS)

Pang, Xiao-Feng; Zhang, Huai-Wu

We calculate the quantum energy spectra of molecular crystals, such as acetanilide, by using discrete nonlinear Schrodinger equation, containing various interactions, appropriate to the systems. The energy spectra consist of many energy bands, in each energy band there are a lot of energy levels including some higher excited states. The result of energy spectrum is basically consistent with experimental values obtained by infrared absorption and Raman scattering in acetanilide and can also explain some experimental results obtained by Careri et al. Finally, we further discuss the influences of variously characteristic parameters on the energy spectra of the systems.

Simulated infrared emission spectra of highly excited polyatomic molecules: a detailed model of the PAH-UIR hypothesis

NASA Technical Reports Server (NTRS)

Cook, D. J.; Saykally, R. J.

1998-01-01

A detailed description of the polycyclic aromatic hydrocarbon (PAH)/unidentified infrared band (UIR) mechanism is presented in which experimental spectral bandshape functions are used to simulate IR emission spectra for individual molecules. These spectra are additively superimposed to produce a conglomerate spectrum representative of a family of PAH molecules. Ab initio vibrational frequencies and intensities for nine PAHs (neutral and cationic) as large as ovalene are used in conjunction with measured bandshape and temperature-dependent redshift data to simulate the UIR bands. The calculated spectra of cations provide a closer match to the UIRs than do those of the neutrals. However, the PAH cations used in the simulations fail to reproduce the details of the UIR emission spectra. The discrepancies are potentially alleviated if both larger PAHs and a greater number of PAHs were included in the simulation.

Near-infrared spectroscopy of primitive solar system objects

NASA Technical Reports Server (NTRS)

Luu, Jane; Jewitt, David; Cloutis, Edward

1994-01-01

We have obtained near-infrared (H and K band at lambda/Delta(lambda) is approximately 480 to 600) spectra of a sample of primitive objects including 2 Centaur objects (2060 Chiron and 5145 Pholus) and 16 P- and D-type asteroids. The spectra were obtained at the United Kingdom Infrared Telescope using the cooled grating spectrometer CGS4, and were used to search for chemically diagnostic vibrational features in these primitive objects. Pholus exhibits broad adsorption features at 2.07 and 2.27 micrometers, as well as a weak feature at 1.72 micrometers. The 1.72- and 2.27-micrometer features are similar to those seen in a laboratory tar sand sample. No distinct absorption features are found in other objects, including Chiron, which displays a spectrally neutral continuum. A comparison of the P- and D-type asteroid spectra with laboratory measurements of organic solids shows no compelling evidence for hydrocarbon overtones seen in terrestrial bituminous tar sands.

Collaborative Study of Analysis of High Resolution Infrared Atmospheric Spectra Between NASA Langley Research Center and the University of Denver

NASA Technical Reports Server (NTRS)

Goldman, Aaron

1999-01-01

The Langley-D.U. collaboration on the analysis of high resolution infrared atmospheric spectra covered a number of important studies of trace gases identification and quantification from field spectra, and spectral line parameters analysis. The collaborative work included: Quantification and monitoring of trace gases from ground-based spectra available from various locations and seasons and from balloon flights. Studies toward identification and quantification of isotopic species, mostly oxygen and Sulfur isotopes. Search for new species on the available spectra. Update of spectroscopic line parameters, by combining laboratory and atmospheric spectra with theoretical spectroscopy methods. Study of trends of atmosphere trace constituents. Algorithms developments, retrievals intercomparisons and automatization of the analysis of NDSC spectra, for both column amounts and vertical profiles.

Simulated aging of lubricant oils by chemometric treatment of infrared spectra: potential antioxidant properties of sulfur structures.

PubMed

Amat, Sandrine; Braham, Zeineb; Le Dréau, Yveline; Kister, Jacky; Dupuy, Nathalie

2013-03-30

Lubricant oils are complex mixtures of base oils and additives. The evolution of their performance over time strongly depends on its resistance to thermal oxidation. Sulfur compounds revealed interesting antioxidant properties. This study presents a method to evaluate the lubricant oil oxidation. Two samples, a synthetic and a paraffinic base oils, were tested pure and supplemented with seven different sulfur compounds. An aging cell adapted to a Fourier Transform InfraRed (FT-IR) spectrometer allows the continuous and direct analysis of the oxidative aging of base oils. Two approaches were applied to study the oxidation/anti-oxidation phenomena. The first one leads to define a new oxidative spectroscopic index based on a reduced spectral range where the modifications have been noticed (from 3050 to 2750 cm(-1)). The second method is based on chemometric treatments of whole spectra (from 4000 to 400 cm(-1)) to extract underlying information. A SIMPLe-to-use Interactive Self Modeling Analysis (SIMPLISMA) method has been used to identify more precisely the chemical species produced or degraded during the thermal treatment and to follow their evolution. Pure spectra of different species present in oil were obtained without prior information of their existence. The interest of this tool is to supply relative quantitative information reflecting evolution of the relative abundance of the different products over thermal aging. Results obtained by these two ways have been compared to estimate their concordance. Copyright © 2013 Elsevier B.V. All rights reserved.

KENNEDY SPACE CENTER, FLA. - A solid rocket booster (SRB) is lifted to vertical on Launch Complex 17-B, Cape Canaveral Air Force Station. The SRB will be attached to the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF). The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. 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. - A solid rocket booster (SRB) is lifted to vertical on Launch Complex 17-B, Cape Canaveral Air Force Station. The SRB will be attached to the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF). The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. 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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, a solid rocket booster (SRB) is lifted into the mobile service tower, joining two others. They are three of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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, a solid rocket booster (SRB) is lifted into the mobile service tower, joining two others. They are three of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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.

KENNEDY SPACE CENTER, FLA. - Workers on Launch Complex 17-B, Cape Canaveral Air Force Station, help steady a solid rocket booster (SRB) being lifted into the mobile service tower. It is one of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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. - Workers on Launch Complex 17-B, Cape Canaveral Air Force Station, help steady a solid rocket booster (SRB) being lifted into the mobile service tower. It is one of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, another solid rocket booster (SRB) is being raised from its transporter to lift it to vertical. It is one of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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, another solid rocket booster (SRB) is being raised from its transporter to lift it to vertical. It is one of nine 46-inch-diameter, stretched SRBs that are being attached to the Delta II Heavy rocket that will 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.

KENNEDY SPACE CENTER, FLA. - Workers at Hangar A&E, Cape Canaveral Air Force Station, help guide the upper canister toward the Space Infrared Telescope Facility (SIRTF) at left. After encapsulation 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. - Workers at Hangar A&E, Cape Canaveral Air Force Station, help guide the upper canister toward the Space Infrared Telescope Facility (SIRTF) at left. After encapsulation 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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is raised off the transporter before lifting it 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 is raised off the transporter before lifting it 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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the first stage of a Delta II rocket is lifted up the mobile service tower. Below the rocket is the flame trench, and in the foreground is the overflow pool. 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 lifted up the mobile service tower. Below the rocket is the flame trench, and in the foreground is the overflow pool. 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.

KENNEDY SPACE CENTER, FLA. - Workers at Hangar A&E, Cape Canaveral Air Force Station, lift the upper canister to move it to the Space Infrared Telescope Facility (SIRTF) at right. After encapsulation, 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. - Workers at Hangar A&E, Cape Canaveral Air Force Station, lift the upper canister to move it to the Space Infrared Telescope Facility (SIRTF) at right. After encapsulation, 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.

KENNEDY SPACE CENTER, FLA. - On Launch Complex 17-B, Cape Canaveral Air Force Station, the Delta II Heavy rocket (background) is framed by the solid rocket boosters (foreground) suspended in the mobile service tower. The SRBs will be added to those already attached to the rocket. The Delta II Heavy will 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 (background) is framed by the solid rocket boosters (foreground) suspended in the mobile service tower. The SRBs will be added to those already attached to the rocket. The Delta II Heavy will 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.

KENNEDY SPACE CENTER, FLA. - Before dawn, the Space Infrared Telescope Facility (SIRTF) arrives at Launch Pad 17-B, Cape Canaveral Air Force Station, where it will be lifted into the mobile service tower and prepared for launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Before dawn, the Space Infrared Telescope Facility (SIRTF) arrives at Launch Pad 17-B, Cape Canaveral Air Force Station, where it will be lifted into the mobile service tower and prepared for launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

Gritty Surface Sample Holder Invented To Obtain Correct X-ray Absorption Fine Structure Spectra for Concentrated Materials by Fluorescence Yield.

PubMed

Abe, Hitoshi; Niwa, Yasuhiro; Kimura, Masao; Murakami, Youichi; Yokoyama, Toshiharu; Hosono, Hideo

2016-04-05

A gritty surface sample holder has been invented to obtain correct XAFS spectra for concentrated samples by fluorescence yield (FY). Materials are usually mixed with boron nitride (BN) to prepare proper concentrations to measure XAFS spectra. Some materials, however, could not be mixed with BN and would be measured in too concentrated conditions to obtain correct XAFS spectra. Consequently, XAFS spectra will be incorrect typically with decreased intensities of the peaks. We have invented the gritty surface sample holders to obtain correct XAFS spectra even for concentrated materials for FY measurements. Pure Cu and CuO powders were measured mounted on the sample holders, and the same spectra were obtained as transmission spectra of properly prepared samples. This sample holder is useful to measure XAFS for any concentrated materials.

Infrared and Visible Absolute and Difference Spectra of Bacteriorhodopsin Photocycle Intermediates

PubMed Central

Hendler, Richard W.; Meuse, Curtis W.; Braiman, Mark S.; Smith, Paul D.; Kakareka, John W.

2014-01-01

We have used new kinetic fitting procedures to obtain IR absolute spectra for intermediates of the main bacteriorhodopsin (bR) photocycle(s). The linear algebra-based procedures of Hendler et al. (2001) J. Phys. Chem. B, 105, 3319–3228, for obtaining clean absolute visible spectra of bR photocycle intermediates, were adapted for use with IR data. This led to isolation, for the first time, of corresponding clean absolute IR spectra, including the separation of the M intermediate into its MF and MS components from parallel photocycles. This in turn permitted the computation of clean IR difference spectra between pairs of successive intermediates, allowing for the most rigorous analysis to date of changes occurring at each step of the photocycle. The statistical accuracy of the spectral calculation methods allows us to identify, with great confidence, new spectral features. One of these is a very strong differential IR band at 1650 cm−1 for the L intermediate at room temperature that is not present in analogous L spectra measured at cryogenic temperatures. This band, in one of the noisiest spectral regions, has not been identified in any previous time-resolved IR papers, although retrospectively it is apparent as one of the strongest L absorbance changes in their raw data, considered collectively. Additionally, our results are most consistent with Arg82 as the primary proton-release group (PRG), rather than a protonated water cluster or H-bonded grouping of carboxylic residues. Notably, the Arg82 deprotonation occurs exclusively in the MF pathway of the parallel cycles model of the photocycle. PMID:21929858

Mid-Infrared Spectroscopy of Mercury from the Kuiper Airborne Observatory

NASA Astrophysics Data System (ADS)

Sprague, A. L.; Witteborn, F. C.; Kozlowski, R. W. H.; Wooden, D. H.

1996-03-01

We present mid-infrared (5 - 10mic) spectroscopic measurements of the planet Mercury obtained from the Kuiper Airborne Observatory (KAO) using the High Efficiency Infrared Faint Object Grating Spectrograph (HIFOGS). Spectra show features characteristic of plagioclase feldspar that was previously observed near 120 deg mercurian longitude. The spectra also show spectral features that could be interpreted indicative of the presence of pyrrhotite (pyrr). An analysis that fully accounts for the effects of large field of view (FOV), thermal gradients, rough surface and absolute calibration is still underway.

Evaluation of different grades of ginseng using Fourier-transform infrared and two-dimensional infrared correlation spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, Yan-ling; Chen, Jian-bo; Lei, Yu; Zhou, Qun; Sun, Su-qin; Noda, Isao

2010-06-01

Ginseng is one of the most widely used herbal medicines which have many kinds of pharmaceutical values. The discrimination of grades of ginseng includes the cultivation types and the growth years herein. To evaluate the different grades of ginseng, the fibrous roots and rhizome roots of ginseng were analyzed by Fourier-transform infrared and two-dimensional infrared correlation spectroscopy in this paper. The fibrous root and rhizome root of ginseng have different content of starch, calcium oxalate and other components. For the fibrous roots of ginseng, mountain cultivation ginseng (MCG), garden cultivation ginseng (GCG) and transplanted cultivation ginseng (TCG) have clear difference in the infrared spectra and second derivative spectra in the range of 1800-400 cm -1, and clearer difference was observed in the range of 1045-1160 and 1410-1730 cm -1 in 2D synchronous correlation spectra. Three kinds of ginseng can be clustered very well by using SIMCA analysis on the basis of PCA as well. For the rhizome roots, the content of calcium oxalate and starch change with growth years in the IR spectra, and some useful procedure can be obtained by the analysis of 2D IR synchronous spectra in the range of 1050-1415 cm -1. Also, ginsengs cultivated in different growth years were clustered perfectly by using SIMCA analysis. The results suggested that different grades of ginseng can be well recognized using the mid-infrared spectroscopy assisted by 2D IR correlation spectroscopy, which provide the macro-fingerprint characteristics of ginseng in different parts and supplied a rapid, effective approach for the evaluation of the quality of ginseng.

Adding a dimension to the infrared spectra of interfaces: 2D SFG spectroscopy via mid-IR pulse shaping

NASA Astrophysics Data System (ADS)

Zanni, Martin

2012-02-01

Sum-frequency generation spectroscopy provides an infrared spectrum of interfaces and thus has widespread use in the materials and chemical sciences. In this presentation, I will present our recent work in developing a 2D pulse sequence to generate 2D SFG spectra of interfaces, in analogy to 2D infrared spectra used to measure bulk species. To develop this spectroscopy, we have utilized many of the tricks-of-the-trade developed in the 2D IR and 2D Vis communities in the last decade, including mid-IR pulse shaping. With mid-IR pulse shaping, the 2D pulse sequence is manipulated by computer programming in the desired frequency resolution, rotating frame, and signal pathway. We believe that 2D SFG will become an important tool in the interfacial sciences in an analogous way that 2D IR is now being used in many disciplines.

Predicting ambient aerosol thermal-optical reflectance measurements from infrared spectra: elemental carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2015-10-01

Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as thermal-optical reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier transform infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive and nondestructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FT-IR spectra are divided into calibration and test sets. Two calibrations are developed: one developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a uniform distribution of Low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the Low EC calibration to Low EC samples and the Uniform EC calibration to all other samples is used to produce predictions for Low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), no bias (0.00 μg m-3, a

Far-infrared Beamline at the Canadian Light Source

NASA Astrophysics Data System (ADS)

Zhao, Jianbao; Billinghurst, Brant

2017-06-01

Far-infrared is a particularly useful technique for studies on lattice modes as they generally appear in the Far-infrared region. Far-infrared is also an important tool for gathering information on the electrical transport properties of metallic materials and the band gap of semiconductors. This poster will describe the horizontal microscope that has recently been built in the Far-infrared beamline at the Canadian Light Source Inc. (CLS). This microscope is specially designed for high-pressure Far-infrared absorbance and reflectance spectroscopic studies. The numerical aperture (0.5) and the long working distance (82.1 mm) in the microscope are good fits for Diamond Anvil Cell (DAC). The spectra are recorded using liquid helium cooled Si bolometer or Ge:Cu detector. The pressure in the DAC can be determined by using the fluorescence spectrometer available onsite. The Far-infrared beamline at CLS is a state-of-the-art synchrotron facility, offering significantly more brightness than conventional sources. Because of the high brightness of the synchrotron radiation, we can obtain the Far-infrared reflectance/absorbance spectra on the small samples with more throughput than with a conventional source. The Far-infrared beamline is open to users through peer review.

Achromatic triplet and athermalized lens assembly for both midwave and longwave infrared spectra

NASA Astrophysics Data System (ADS)

Kuo, Chih-Wei

2014-02-01

Analytic solutions for finding the achromatic triplet in the midwave and longwave infrared spectra simultaneously are explored. The relationship between the combination of promising refractive materials and the system's optical power is also formulated. The principles for stabilizing the effective focal length of an air-spaced lens group with respect to temperature are explored, and the thermal properties of the optical component and mechanical elements mutually counterbalanced. An optical design based on these achromatic and athermal theories is demonstrated, and the image quality of the lens assembly seems to approach the diffractive limitation.

Development of Infrared Library Search Prefilters for Automotive Clear Coats from Simulated Attenuated Total Reflection (ATR) Spectra.

PubMed

Perera, Undugodage Don Nuwan; Nishikida, Koichi; Lavine, Barry K

2018-06-01

A previously published study featuring an attenuated total reflection (ATR) simulation algorithm that mitigated distortions in ATR spectra was further investigated to evaluate its efficacy to enhance searching of infrared (IR) transmission libraries. In the present study, search prefilters were developed from transformed ATR spectra to identify the assembly plant of a vehicle from ATR spectra of the clear coat layer. A total of 456 IR transmission spectra from the Paint Data Query (PDQ) database that spanned 22 General Motors assembly plants and served as a training set cohort were transformed into ATR spectra by the simulation algorithm. These search prefilters were formulated using the fingerprint region (1500 cm -1 to 500 cm -1 ). Both the transformed ATR spectra (training set) and the experimental ATR spectra (validation set) were preprocessed for pattern recognition analysis using the discrete wavelet transform, which increased the signal-to-noise of the ATR spectra by concentrating the signal in specific wavelet coefficients. Attenuated total reflection spectra of 14 clear coat samples (validation set) measured with a Nicolet iS50 Fourier transform IR spectrometer were correctly classified as to assembly plant(s) of the automotive vehicle from which the paint sample originated using search prefilters developed from 456 simulated ATR spectra. The ATR simulation (transformation) algorithm successfully facilitated spectral library matching of ATR spectra against IR transmission spectra of automotive clear coats in the PDQ database.

Analysis of bacteria on steel surfaces using reflectance micro-Fourier transform infrared spectroscopy.

PubMed

Ojeda, Jesús J; Romero-González, María E; Banwart, Steven A

2009-08-01

Reflectance micro-Fourier transform infrared (FT-IR) analysis has been applied to characterize biofilm formation of Aquabacterium commune, a common microorganism present on drinking water distribution systems, onto the increasingly popular pipe material stainless steel EN1.4307. The applicability of the reflectance micro-FT-IR technique for analyzing the bacterial functional groups is discussed, and the results are compared to spectra obtained using more conventional FT-IR techniques: transmission micro-FT-IR, attenuated transmitted reflectance (ATR), and KBr pellets. The differences between the infrared spectra of wet and dried bacteria, as well as free versus attached bacteria, are also discussed. The spectra obtained using reflectance micro-FT-IR spectroscopy were comparable to those obtained using other FT-IR techniques. The absence of sample preparation, the potential to analyze intact samples, and the ability to characterize opaque and thick samples without the need to transfer the bacterial samples to an infrared transparent medium or produce a pure culture were the main advantages of reflectance micro-FT-IR spectroscopy.

Infrared spectroscopy of molecular submonolayers on surfaces by infrared scanning tunneling microscopy: tetramantane on Au111.

PubMed

Pechenezhskiy, Ivan V; Hong, Xiaoping; Nguyen, Giang D; Dahl, Jeremy E P; Carlson, Robert M K; Wang, Feng; Crommie, Michael F

2013-09-20

We have developed a new scanning-tunneling-microscopy-based spectroscopy technique to characterize infrared (IR) absorption of submonolayers of molecules on conducting crystals. The technique employs a scanning tunneling microscope as a precise detector to measure the expansion of a molecule-decorated crystal that is irradiated by IR light from a tunable laser source. Using this technique, we obtain the IR absorption spectra of [121]tetramantane and [123]tetramantane on Au(111). Significant differences between the IR spectra for these two isomers show the power of this new technique to differentiate chemical structures even when single-molecule-resolved scanning tunneling microscopy (STM) images look quite similar. Furthermore, the new technique was found to yield significantly better spectral resolution than STM-based inelastic electron tunneling spectroscopy, and to allow determination of optical absorption cross sections. Compared to IR spectroscopy of bulk tetramantane powders, infrared scanning tunneling microscopy (IRSTM) spectra reveal narrower and blueshifted vibrational peaks for an ordered tetramantane adlayer. Differences between bulk and surface tetramantane vibrational spectra are explained via molecule-molecule interactions.

Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results

NASA Technical Reports Server (NTRS)

Clark, Beth Ellen; Shepard, M.; Bus, S. J.; Vilas, F.; Rivkin, A. S.; Lim, L.; Lederer, S.; Jarvis, K.; Shah, S.; McConnochie, T.

2004-01-01

The August 2003 apparition of asteroid 2100 Ra-Shalom brought together a collaboration of observers with the goal of obtaining rotationally resolved multiwavelength spectra at each of 5 facilities: infrared spectra at the NASA Infrared Telescope Facility (Clark and Shepard), radar images at Arecibo (Shepard and Clark), thermal infrared spectra at Palomar (Lim, McConnochie and Bell), visible spectra at McDonald Observatory (Vilas, Lederer and Jarvis), and visible lightcurves at Ondrojev Observatory (Pravec). The radar data was to be used to develop a high spatial resolution physical model to be used in conjunction with spectral data to investigate compositional and textural properties on the near surface of Ra Shalom as a function of rotation phase. This was the first coordinated multi-wavelength investigation of any Aten asteroid. There are many reasons to study near-Earth asteroid (NEA) 2100 Ra-Shalom: 1) It has a controversial classification (is it a C- or K-type object)? 2) There would be interesting dynamical ramifications if Ra-Shalom is a K-type because most K-types come from the Eos family and there are no known dynamical pathways from Eos to the Aten population. 3) The best available spectra obtained previously may indicate a heterogeneous surface (most asteroids appear to be fairly homogeneous). 4) Ra-Shalom thermal observations obtained previously indicated a lack of regolith, minimizing the worry of space weathering effects in the spectra. 5) Radar observations obtained previously hinted at interesting surface structures. 6) Ra-Shalom is one of the largest Aten objects. And 7) Ra-Shalom is on a short list of proposed NEAs for spacecraft encounters and possible sample returns. Preliminary results from the visible, infrared, and thermal spectroscopy measurements will be presented here.

Correlation of vapor phase infrared spectra and regioisomeric structure in synthetic cannabinoids

NASA Astrophysics Data System (ADS)

Smith, Lewis W.; Thaxton-Weissenfluh, Amber; Abiedalla, Younis; DeRuiter, Jack; Smith, Forrest; Clark, C. Randall

2018-05-01

The twelve 1-n-pentyl-2-, 3-, 4-, 5-, 6- and 7-(1- and 2-naphthoyl)-indoles each have the same substituents attached to the indole ring, identical elemental composition (C24H23NO) yielding identical nominal and accurate masses. These twelve isomers cover all possible positions of carbonyl bridge substitution for both indole (positons 2-7) and naphthalene rings (positions 1 and 2). Regioisomeric compounds can represent significant challenges for mass based analytical methods however, infrared spectroscopy is a powerful tool for the identification of positional isomers in organic compounds. The vapor phase infrared spectra of these twelve uniquely similar compounds were evaluated in GC-IR experiments. These spectra show the bridge position on the indole ring is a dominating influence over the carbonyl absorption frequency observed for these compounds. Substitution on the pyrrole moiety of the indole ring yields the lowest Cdbnd O frequency values for position 2 and 3 giving a narrow range from 1656 to 1654 cm-1. Carbonyl absorption frequencies are higher when the naphthoyl group is attached to the benzene portion of the indole ring yielding absorption values from 1674 to 1671 cm-1. The aliphatic stretching bands in the 2900 cm-1 region yield a consistent triplet pattern because the N-alkyl substituent tail group remains unchanged for all twelve regioisomers. The asymmetric CH2 stretch is the most intense of these three bands. Changes in positional bonding for both the indole and naphthalene ring systems results in unique patterns within the 700 wavenumber out-of-plane region and these absorption bands are different for all 12 regioisomers.

Theoretical study of NMR, infrared and Raman spectra on triple-decker phthalocyanines

NASA Astrophysics Data System (ADS)

Suzuki, Atsushi; Oku, Takeo

2016-02-01

Electronic structures and magnetic properties of multi-decker phthalocyanines were studied by theoretical calculation. Electronic structures, excited processes at multi-states, isotropic chemical shifts of 13C, 14N and 1H-nuclear magnetic resonance (NMR), principle V-tensor in electronic field gradient (EFG) tensor and asymmetry parameters (η), vibration mode in infrared (IR) and Raman spectra of triple-decker phthalocyanines were calculated by density functional theory (DFT) and time-dependent DFT using B3LYP as basis function. Electron density distribution was delocalized on the phthalocyanine rings with electron static potential. Considerable separation of chemical shifts in 13C, 14N and 1H-NMR was originated from nuclear spin interaction between nitrogen and carbon atoms, nuclear quadrupole interaction based on EFG and η of central metal under crystal field. Calculated optical absorption at multi-excited process was derived from overlapping π-orbital on the phthalocyanine rings. The vibration modes in IR and Raman spectra were based on in-plane deformation and stretching vibrations of metal-ligand coordination bond on the deformed structure.

Matrix infrared spectra and electronic structure calculations of the first actinide borylene: FB=ThF(2).

PubMed

Wang, Xuefeng; Roos, Björn O; Andrews, Lester

2010-03-14

Laser-ablated Th atoms react with BF(3) during condensation in excess argon at 6 K to form the first actinide borylene (FB=ThF(2)) and actinide-boron multiple bond. Three new product absorptions in the B-F and Th-F stretching regions of matrix infrared spectra are assigned to FB=ThF(2) from comparison to theoretically predicted vibrational frequencies.

A synthetic data set of high-spectral-resolution infrared spectra for the Arctic atmosphere

NASA Astrophysics Data System (ADS)

Cox, Christopher J.; Rowe, Penny M.; Neshyba, Steven P.; Walden, Von P.

2016-05-01

Cloud microphysical and macrophysical properties are critical for understanding the role of clouds in climate. These properties are commonly retrieved from ground-based and satellite-based infrared remote sensing instruments. However, retrieval uncertainties are difficult to quantify without a standard for comparison. This is particularly true over the polar regions, where surface-based data for a cloud climatology are sparse, yet clouds represent a major source of uncertainty in weather and climate models. We describe a synthetic high-spectral-resolution infrared data set that is designed to facilitate validation and development of cloud retrieval algorithms for surface- and satellite-based remote sensing instruments. Since the data set is calculated using pre-defined cloudy atmospheres, the properties of the cloud and atmospheric state are known a priori. The atmospheric state used for the simulations is drawn from radiosonde measurements made at the North Slope of Alaska (NSA) Atmospheric Radiation Measurement (ARM) site at Barrow, Alaska (71.325° N, 156.615° W), a location that is generally representative of the western Arctic. The cloud properties for each simulation are selected from statistical distributions derived from past field measurements. Upwelling (at 60 km) and downwelling (at the surface) infrared spectra are simulated for 260 cloudy cases from 50 to 3000 cm-1 (3.3 to 200 µm) at monochromatic (line-by-line) resolution at a spacing of ˜ 0.01 cm-1 using the Line-by-line Radiative Transfer Model (LBLRTM) and the discrete-ordinate-method radiative transfer code (DISORT). These spectra are freely available for interested researchers from the NSF Arctic Data Center data repository (doi:10.5065/D61J97TT).

Far-Infrared and Raman Spectra and The Ring-Twisting Potential Energy Function of 1,3-Cyclohexadiene

NASA Astrophysics Data System (ADS)

Autrey, Daniel; Choo, Jaebum; Laane, Jaan

2001-10-01

The nu19 (A2) ring-twisting vibration of 1,3-cyclohexadiene has been analyzed from the vapor-phase Raman and infrared spectra. The Raman spectrum shows nine ring-twisting transitions in the 116 - 199 cm-1 region. The far-infrared spectrum confirms five of these transitions, despite the fact that the vibration is infrared forbidden in the C2v (planar) approximation. Other Raman and infrared combination bands verify the assignments and provide information on the vibrational coupling. A coordinate dependent kinetic energy expansion for the ring-twisting motion was calculated, and this was used to determine the ring-twisting potential function, which has a barrier to planarity of 1132 cm-1 and energy minima corresponding to twisting angles of 9.1º and 30.1º. Ab initio calculations were also carried out using Moller-Plesset perturbation theory (MP2) with a large number of different basis sets. The various ab initio calculations gave barriers to planarity in the 1197 - 1593 cm-1 range and calculated vibrational frequencies in excellent agreement with the experimental values.

Measurements of trace constituents from atmospheric infrared emission and absorption spectra, a feasibility study

NASA Technical Reports Server (NTRS)

Goldman, A.; Williams, W. J.; Murcray, D. G.

1974-01-01

The feasibility of detecting eight trace constituents (CH4, HCl, HF, HNO3, NH3, NO, NO2 and SO2) against the rest of the atmospheric background at various altitudes from infrared emission and absorption atmospheric spectra was studied. Line-by-line calculations and observational data were used to establish features that can be observed in the atmospheric spectrum due to each trace constituent. Model calculations were made for experimental conditions which approximately represent state of the art emission and absorption spectrometers.

Thermally and vibrationally induced conformational isomerizations, infrared spectra, and photochemistry of gallic acid in low-temperature matrices

NASA Astrophysics Data System (ADS)

Justino, Licínia L. G.; Reva, Igor; Fausto, Rui

2016-07-01

Near-infrared (near-IR) narrowband selective vibrational excitation and annealing of gallic acid (3,4,5-trihydroxybenzoic acid) isolated in cryogenic matrices were used to induce interconversions between its most stable conformers. The isomerizations were probed by infrared spectroscopy. An extensive set of quantum chemical calculations, carried out at the DFT(B3LYP)/6-311++G(d,p) level of approximation, was used to undertake a detailed analysis of the ground state potential energy surface of the molecule. This investigation of the molecule conformational space allowed extracting mechanistic insights into the observed annealing- or near-IR-induced isomerization processes. The infrared spectra of the two most stable conformers of gallic acid in N2, Xe, and Ar matrices were fully assigned. Finally, the UV-induced photochemistry of the matrix isolated compound was investigated.

Fourier transform infrared emission spectra of MnH and MnD

NASA Astrophysics Data System (ADS)

Gordon, Iouli E.; Appadoo, Dominique R. T.; Shayesteh, Alireza; Walker, Kaley A.; Bernath, Peter F.

2005-01-01

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X7Σ + electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm -1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant ( ωe) for MnH was found to be 1546.84518(65) cm -1, the equilibrium rotational constant ( Be) is 5.6856789(103) cm -1 and the eqilibrium bond distance ( re) was determined to be 1.7308601(47) Å.

[Investigation of typical melamine urinary stones using infrared spectra].

PubMed

Si, Min-Zhen; Li, Qing-Yun; Liu, Ren-Ming; Kang, Yi-Pu; Wang, Kun-Hua; Zhang, Zhi-Guo

2010-02-01

A typical melamine kidney stone confirmed by some medicine expert was collected from the first people's hospital of Yunnan. The kidney stone was adequately determined by PE corporation spectra 100(with resolution of 1 cm(-1)). The stone samples for FTIR analysis were prepared using the KBr pellet technique, where 2 mg of the pretreated stone powder was mixed with 200 mg of analytical grade KBr using an agate pestle and mortar. The digital spectrum was then scanned in the mid-infrared region from 4 000 to 400 cm(-1) at room temperature. The appearing bands between 4 000 and 2 000 cm(-1) were 3 487, 3 325, 3 162 and 2 788 cm(-1), those between 1 700 and 1 000 cm(-1) were 1 694, 1 555, 1 383, 1 340, 1 189 and 1 122 cm(-1), and those between 1 000 and 400 cm(-1) were 993, 782, 748, 709, 624, 585, 565 and 476 cm(-1). It was found that the main constituent of calculi showed few comparability with cat kidney stone, which was from cats that died after consuming the contaminated food, and confirmed that these deposits were primarily composed of melamine and cyanuric acid compared to the IR spectra of calculi in literature. It was also found that the main constituent of calculi showed few comparability with popular kidney stone by comparison with the IR spectra of calculi in literature. The spectrum of calculi was 50% respectively similar with melamine and uric acid as compared with the IR spectrum. It was found that the main constituent of calculi was melamine itself and uric acid as compared with the IR spectra of calculi and melamine: (1 : 1), because the spectrum of calculi was 83. 3% similar to melamine and uric acid (1 : 1). The appearing bands of melamine and uric acid (1 : 1) between 4 000 and 2 000 cm(-1) were 3 469, 3 419, 3 333, 3 132, 3 026, 2 827 cm(-1), those between 1 700 and 1 000 cm(-1) were 1 696, 1 656, 1 555, 1 489, 1 439, 1 350, 1 311, 1 198, 1 124 and 1 028 cm(-1), and those between 1 000 and 400 cm(-1) were 993, 878, 814, 784, 745, 708, 619, 577 and

Infrared frequencies and intensities for astrophysically important polycyclic aromatic hydrocarbon cations

NASA Technical Reports Server (NTRS)

Szczepanski, Jan; Vala, Martin

1993-01-01

Polycyclic aromatic hydrocarbons (PAHs) have been implicated as the carriers of the 'unidentified infrared' (UIR) emission bands observed from the interstellar medium. It has long been thought that these molecules, if present, probably exist as cations. In this paper we present infrared spectra of the cations of five moderate-sized PAHs. The PAH cations have been produced by low-energy electron impact and then trapped and stabilized in argon matrices at 12 K. To date, results have been obtained on naphthalene, anthracene, pyrene, perylene, and coronene. A common feature of the infrared spectra of all these cations is the very different intensity pattern of the ions compared to the neutral parents. Visible and (partial) infrared spectra of the coronene cation are also presented. It is shown that the out-of-plane CH bending mode shifts to a position very close to the UIR band at 11.3 microns. The astrophysical impact of these observations is discussed.

Soil emissivity and reflectance spectra measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sobrino, Jose A.; Mattar, Cristian; Pardo, Pablo

We present an analysis of the laboratory reflectance and emissivity spectra of 11 soil samples collected on different field campaigns carried out over a diverse suite of test sites in Europe, North Africa, and South America from 2002 to 2008. Hemispherical reflectance spectra were measured from 2.0 to 14 {mu}m with a Fourier transform infrared spectrometer, and x-ray diffraction analysis (XRD) was used to determine the mineralogical phases of the soil samples. Emissivity spectra were obtained from the hemispherical reflectance measurements using Kirchhoff's law and compared with in situ radiance measurements obtained with a CIMEL Electronique CE312-2 thermal radiometer andmore » converted to emissivity using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) temperature and emissivity separation algorithm. The CIMEL has five narrow bands at approximately the same positions as the ASTER. Results show a root mean square error typically below 0.015 between laboratory emissivity measurements and emissivity measurements derived from the field radiometer.« less

Monitoring breast cancer treatment using a Fourier transform infrared spectroscopy-based computational model.

PubMed

Depciuch, J; Kaznowska, E; Golowski, S; Koziorowska, A; Zawlik, I; Cholewa, M; Szmuc, K; Cebulski, J

2017-09-05

Breast cancer affects one in four women, therefore, the search for new diagnostic technologies and therapeutic approaches is of critical importance. This involves the development of diagnostic tools to facilitate the detection of cancer cells, which is useful for assessing the efficacy of cancer therapies. One of the major challenges for chemotherapy is the lack of tools to monitor efficacy during the course of treatment. Vibrational spectroscopy appears to be a promising tool for such a purpose, as it yields Fourier transformation infrared (FTIR) spectra which can be used to provide information on the chemical composition of the tissue. Previous research by our group has demonstrated significant differences between the infrared spectra of healthy, cancerous and post-chemotherapy breast tissue. Furthermore, the results obtained for three extreme patient cases revealed that the infrared spectra of post-chemotherapy breast tissue closely resembles that of healthy breast tissue when chemotherapy is effective (i.e., a good therapeutic response is achieved), or that of cancerous breast tissue when chemotherapy is ineffective. In the current study, we compared the infrared spectra of healthy, cancerous and post-chemotherapy breast tissue. Characteristic parameters were designated for the obtained spectra, spreading the function of absorbance using the Kramers-Kronig transformation and the best fit procedure to obtain Lorentz functions, which represent components of the bands. The Lorentz function parameters were used to develop a physics-based computational model to verify the efficacy of a given chemotherapy protocol in a given case. The results obtained using this model reflected the actual patient data retrieved from medical records (health improvement or no improvement). Therefore, we propose this model as a useful tool for monitoring the efficacy of chemotherapy in patients with breast cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Collaborative Study for Analysis of High Resolution Infrared Atmospheric Spectra Between NASA Langley Research Center and the University of Denver

NASA Technical Reports Server (NTRS)

Goldman, A.

2002-01-01

The Langley-D.U. collaboration on the analysis of high resolultion infrared atmospheric spectra covered a number of important studies of trace gases identification and quantification from field spectra, and spectral line parameters analysis. The collaborative work included: 1) Quantification and monitoring of trace gases from ground-based spectra available from various locations and seasons and from balloon flights; 2) Identification and preliminary quantification of several isotopic species, including oxygen and Sulfur isotopes; 3) Search for new species on the available spectra, including the use of selective coadding of ground-based spectra for high signal to noise; 4) Update of spectroscopic line parameters, by combining laboratory and atmospheric spectra with theoretical spectroscopy methods; 5) Study of trends and correlations of atmosphere trace constituents; and 6) Algorithms developments, retrievals intercomparisons and automatization of the analysis of NDSC spectra, for both column amounts and vertical profiles.

[Comparative studies on the characteristics of the Fourier-transform infrared spectra between sturgeon and shark chondroitin sulfates].

PubMed

Zheng, Jiang; Guan, Rui-Zhang; Huang, Shi-Yu

2008-01-01

The characteristics of the Fourier-transform infrared spectra of sturgeon and shark chondroitin sulfates (CHSs) were comparatively studied. The results show that sturgeon CHS exhibits special vibrations at the wavenumbers of 1 376, 1 344, 1 310, 1 157, 883 and 856 cm(-1). Further analysis shows that shark CHS contains 6-sulfated-CHS, while sturgeon CHS contains 4, 6-disulfated CHS, indicating that sturgeon CHS could have higher biological activities in decreasing the toxicity of medicine and in killing cancer cells. In general, the two kinds of CHSs have similar infrared spectra and groups of acylamino, carboxyl, sulfate, and saccharide ring. But the N-H variable-angle vibration of acylamino group of sturgeon CHS occurs at the higher wavenumber, and the vibration intensity of carboxyl group at 1 415 cm(-1) is also stronger than that of shark CHS. Chemical analysis shows that sturgeon CHS has a higher content of glucuronic acid, suggesting that it probably could be a better kind of medical materials for the bone mineralization.

Cryogenic Infrared Reflectance Spectra of Organic Ices and Their Relevance to the Surface Composition of Titan

NASA Astrophysics Data System (ADS)

Curchin, John; Clark, R. N.; Hoefen, T. M.

2006-09-01

In order to properly interpret reflectance spectra of Titan's surface, laboratory spectra of candidate materials for comparative analysis is needed. Although the common cosmochemical species (H2O, CO2, CO, NH3, and CH4) are well represented in the spectroscopic literature, comparatively little reflectance work has been done on organics at cryotemperatures at visible to near infrared wavelengths. Measurement of reflectance is required for characterizing weak features not seen in transmittance. Such features may be important in remote sensing of planetary surfaces. The USGS Spectroscopy Laboratory uses Nicolet FT-IR and ASD field spectrometers in combination with cryogenic chambers to acquire reflectance spectra of organic ices at approximately 80-90 ºK in a wavelength range of 0.35 to 15.5 microns. This region encompasses the fundamental absorptions and many overtones and combinations of major organic molecules including those with hydrogen-carbon, carbon-carbon (single, double and triple bonds), carbon-oxygen, oxygen-hydrogen, carbon-nitrogen, and nitrogen-hydrogen bonds. Because most organic compounds belong to families with similar structure and composition, individual species identification within a narrow wavelength range may be ambiguous. Only by measuring spectral reflectance of the pure laboratory ices from the visible through the near and mid-infrared can absorption bands unique to each be observed, cataloged and compared to planetary reflectance data. We present here spectra of organic ices belonging to eight families, the alkanes, cycloalkanes, alkenes, alkynes, aromatics, nitriles, amines, and cyanides. Many of these compounds are predicted to coat the surface of Titan and indeed, a number of atmospheric windows, particularly at 5 microns, have allowed their identification with VIMS (Clark et al., DPS 2006, this volume). The spectral properties of these materials have applications to other solar system surfaces and remote sensing of terrestrial

The Mid-Infrared Absorption Spectra of Neutral PAHs in Dense Interstellar Clouds

NASA Technical Reports Server (NTRS)

Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.

2005-01-01

Polycyclic aromatic hydrocarbons (PAHs) are common throughout the universe and are expected to be present in dense interstellar clouds. In these environments, some P.4Hs may be present in the gas phase, but most should be frozen into ice mantles or adsorbed onto dust grains and their spectral features are expected to be seen in absorption. Here we extend our previous work on the infrared spectral properties of the small PAH naphthalene (C10H8) in several media to include the full mid-infrared laboratory spectra of 11 other PAHs and related aromatic species frozen in H2O ices. These include the molecules 1,2-dihydronaphthalene, anthracene, 9,1O-dihydroanthracene, phenanthrene, pyrene, benzo[e]pyrene, perylene, benzo(k)fluoranthene, pentacene, benzo[ghi]perylene, and coronene. These results demonstrate that PAHs and related molecules, as a class, show the same spectral behaviors as naphthalene when incorporated into H2O-rich matrices. When compared to the spectra of these same molecules isolated in inert matrices (e.g., Ar or N2), the absorption bands produced when they are frozen in H2O matrices are broader (factors of 3-10), show small position shifts in either direction (usually < 4/cm, always < 10/cm), and show variable changes in relative band strengths (typically factors of 1-3). There is no evidence of systematic increases or decreases in the absolute strengths of the bands of these molecules when they are incorporated in H2O matrices. In H2O-rich ices, their absorption bands are relatively insensitive to concentration over the range of 10 < H2O/PAH < 200): The absorption bands of these molecules are also insensitive to temperature over the 10 K < T < 125 K range, although the spectra can show dramatic changes as the ices are warmed through the temperature range in which amorphous H2O ice converts to its cubic and hexagonal crystalline forms (T > 125 Kj. Given the small observed band shifts cause by H2O, the current database of spectra from Ar matrix

Infrared spectra and other properties predictions of 5-amino-3-methyl-4-isoxazolecarbohydrazide with electric field simulation using CPC model

NASA Astrophysics Data System (ADS)

Regiec, Andrzej; Wojciechowski, Piotr; Pietraszko, Adam; Mączyński, Marcin

2018-06-01

Here, the Conductor-like Polarizable Continuum Model (CPCM) was used as a less demanding substitute of Periodic Boundary Conditions (PBC) method to attempt to reliably simulate infrared spectra and some structural parameters of solid compound - 5-amino-3-methyl-4-isoxazolecarbohydrazide (HIX). The measured relative electric permittivity of HIX was used as a simplified equivalent of electric intensity generating by other molecules of 5-amino-3-methyl-4-isoxazolecarbohydrazide in crystal structure. The application of CPCM has resulted in better conformity of calculated molecular parameters with experimentally found. Theoretical geometry was compared with data obtained with X-ray crystallography. Comparison of harmonic approximation with anharmonic one, based on the six selected characteristic vibrations, shows that non-scaled harmonic wavenumbers, calculated with CPCM, well correspond to experimental spectra. Additionally, the results point out that anharmonic approximation appeared to be strong sensitive for input geometry and calculation parameters used, so the results are sometimes unreliable, especially for low wavenumbers. Also, the new feasible ways of the synthesis of the titled compound is presented, one of which is particularly easy and highly efficient.

High-Resolution Infrared Spectra of Spiropentane, C5H8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, Joseph E.; Coulterpark, K. A.; Masiello, Tony

2011-09-01

Infrared spectra of spiropentane (C{sub 5}H{sub 8}) have been recorded at a resolution (0.002 cm{sup -1}) sufficient to resolve for the first time individual rovibrational lines. This initial report presents the ground state constants for this molecule determined from the detailed analysis of the {nu}16 (b2) parallel band at 993 cm{sup -1}. In addition, the determination included more than 2000 ground state combination-differences deduced from partial analyses of four other infrared-allowed bands, the {nu}24(e) perpendicular band at 780 cm{sup -1} and three (b2) parallel bands at 1540 cm{sup -1} ({nu}14), 1568 cm{sup -1} ({nu}5+{nu}16), and 2098 cm{sup -1} ({nu}5+{nu}14). Inmore » each of the latter four cases, the spectra show complications; in the case of {nu}24, these complications are due to rotational l-type doublings, and in the case of the parallel bands, the spectral complexities are due to Fermi resonance and Coriolis interactions of the upper states with nearby levels. The unraveling of these is underway but the assignment of many of these transitions permit the confident use of the ground state differences in determining the following constants for the ground state (in units of cm{sup -1}): B0 = 0.1394736(2), DJ = 2.458(1) x 10{sup -8}, DJK = 8.28(3) x 10{sup -8}. For the unperturbed {nu}16 fundamental, more than 3000 transitions were fit and the band origin was found to be at 992.53793(2) cm{sup -1}. The numbers in parentheses are the uncertainties (two standard deviations) in the value of the last digit of the constants. Surprisingly, the very accurate B0 value measured here is lower than the value (0.1418 cm{sup -1}) calculated from an electron diffraction structure, instead of being higher, as expected. Where possible, the rovibrational results are compared with those computed at the anharmonic level using the B3LYP density functional method with a cc-pVTZ basis set. These too suggest that the electron diffraction results are in question.« less

A high-resolution atlas of the infrared spectrum of the Sun and the Earth atmosphere from space: A compilation of ATMOS spectra of the region from 650 to 4800 cm (2.3 to 16 micron). Volume 1: The Sun

NASA Technical Reports Server (NTRS)

Farmer, Crofton B.; Norton, Robert H.

1989-01-01

During the period April 29 through May 2, 1985, the Atmospheric Trace Molecular Spectroscopy experiment was operated as part of the Spacelab-3 payload of the shuttle Challenger. The instrument, a modified Michelson Interferometer covering the frequency range from 600 to 5000/cm, at a spectral resolution of 0.01/cm, recorded infrared spectra of the Sun and of the Earth's atmosphere at times close to entry into and exit from occultation by the Earth's limb as seen from the shuttle orbit of 360 km. Spectra were obtained that are free from absorptions due to constituents of the atmosphere (i.e., solar pure spectra), as well as spectra of the atmosphere itself, covering line-of-sight tangent altitudes that span the range from the lower thermosphere to the bottom of the troposphere. This atlas, believed to be the first record of observations of the continuous high resolution infrared spectrum of the Sun and the Earth's atmosphere from space, provides a compilation of these spectra arranged in a hardcopy format suitable for quick-look reference purposes; the data are also available in digital form.

Obtaining high-resolution velocity spectra using weighted semblance

NASA Astrophysics Data System (ADS)

Ebrahimi, Saleh; Kahoo, Amin Roshandel; Porsani, Milton J.; Kalateh, Ali Nejati

2017-02-01

Velocity analysis employs coherency measurement along a hyperbolic or non-hyperbolic trajectory time window to build velocity spectra. Accuracy and resolution are strictly related to the method of coherency measurements. Semblance, the most common coherence measure, has poor resolution velocity which affects one's ability to distinguish and pick distinct peaks. Increase the resolution of the semblance velocity spectra causes the accuracy of estimated velocity for normal moveout correction and stacking is improved. The low resolution of semblance spectra depends on its low sensitivity to velocity changes. In this paper, we present a new weighted semblance method that ensures high-resolution velocity spectra. To increase the resolution of semblance spectra, we introduce two weighting functions based on the first to second singular values ratio of the time window and the position of the seismic wavelet in the time window to the semblance equation. We test the method on both synthetic and real field data to compare the resolution of weighted and conventional semblance methods. Numerical examples with synthetic and real seismic data indicate that the new proposed weighted semblance method provides higher resolution than conventional semblance and can separate the reflectors which are mixed in the semblance spectrum.

Near-infrared spectra of the Martian surface: Reading between the lines

NASA Technical Reports Server (NTRS)

Crisp, D.; Bell, J. F., III

1993-01-01

Moderate-resolution near-infrared (NIR) spectra of Mars have been widely used in studies of the Martian surface because many candidate surface materials have distinctive absorption features at these wavelengths. Recent advances in NIR detector technology and instrumentation have also encouraged studies in this spectral region. The use of moderate spectral resolution has often been justified for NIR surface observations because the spectral features produced by most surface materials are relatively broad, and easily discriminated at this resolution. In spite of this, NIR spectra of Mars are usually very difficult to interpret quantitatively. One problem is that NIR surface absorption features are often only a few percent deep, requiring observations with great signal-to-noise ratios. A more significant problem is that gases in the Martian atmosphere contribute numerous absorption features at these wavelengths. Ground-based observers must also contend with variable absorption by several gases in the Earth's atmosphere (H2O, CO2, O3, N2O, CH4, O2). The strong CO2 bands near 1.4, 1.6, 2.0, 2.7, 4.3, and 4.8 micrometers largely preclude the analysis of surface spectral features at these wavelengths. Martian atmospheric water vapor also contributes significant absorption near 1.33, 1.88, and 2.7 micrometers, but water vapor in the Earth's atmosphere poses a much larger problem to ground-based studies of these spectral regions. The third most important NIR absorber in the Martian atmosphere is CO. This gas absorbs most strongly in the relatively-transparent spectral windows near 4.6 and 2.3 micrometers. It also produces 1-10 percent absorption in the solar spectrum at these NIR wavelengths. This solar CO absorption cannot be adequately removed by dividing the Martian spectrum by that of a star, as is commonly done to calibrate ground-based spectroscopic observations, because most stars do not have identical amounts of CO absorption in their spectra. Here, we describe tow

Thermally and vibrationally induced conformational isomerizations, infrared spectra, and photochemistry of gallic acid in low-temperature matrices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Justino, Licínia L. G., E-mail: liciniaj@ci.uc.pt; Reva, Igor; Fausto, Rui

2016-07-07

Near-infrared (near-IR) narrowband selective vibrational excitation and annealing of gallic acid (3,4,5-trihydroxybenzoic acid) isolated in cryogenic matrices were used to induce interconversions between its most stable conformers. The isomerizations were probed by infrared spectroscopy. An extensive set of quantum chemical calculations, carried out at the DFT(B3LYP)/6-311++G(d,p) level of approximation, was used to undertake a detailed analysis of the ground state potential energy surface of the molecule. This investigation of the molecule conformational space allowed extracting mechanistic insights into the observed annealing- or near-IR-induced isomerization processes. The infrared spectra of the two most stable conformers of gallic acid in N{sub 2},more » Xe, and Ar matrices were fully assigned. Finally, the UV-induced photochemistry of the matrix isolated compound was investigated.« less

Surface-Enhanced Hyper-Raman Spectra of Adenine, Guanine, Cytosine, Thymine, and Uracil

PubMed Central

2016-01-01

Using picosecond excitation at 1064 nm, surface-enhanced hyper-Raman scattering (SEHRS) spectra of the nucleobases adenine, guanine, cytosine, thymine, and uracil with two different types of silver nanoparticles were obtained. Comparing the SEHRS spectra with SERS data from the identical samples excited at 532 nm and with known infrared spectra, the major bands in the spectra are assigned. Due to the different selection rules for the one- and two-photon excited Raman scattering, we observe strong variation in relative signal strengths of many molecular vibrations obtained in SEHRS and SERS spectra. The two-photon excited spectra of the nucleobases are found to be very sensitive with respect to molecule–nanoparticle interactions. Using both the SEHRS and SERS data, a comprehensive vibrational characterization of the interaction of nucleobases with silver nanostructures can be achieved. PMID:28077982

Conformational stability, structural parameters and vibrational assignment from variable temperature infrared spectra of krypton solutions and ab initio calculations of ethylisothiocyanate.

PubMed

Durig, James R; Zheng, Chao

2007-11-01

Variable temperature (-105 to -150 degrees C) studies of the infrared spectra (3500-400 cm(-1)) of ethylisothiocyanate, CH(3)CH(2)NCS, dissolved in liquid krypton have been recorded. Additionally the infrared spectra of the gas and solid have been re-investigated. These spectroscopic data indicate a single conformer in all physical states with a large number of molecules in the gas phase at ambient temperature in excited states of the CN torsional mode which has a very low barrier to conformational interchange. To aid in the analyses of the vibrational and rotational spectra, ab initio calculations have been carried out by the perturbation method to the second order (MP2) with valence and core electron correlation using a variety of basis sets up to 6-311+G(2df,2pd). With the smaller basis sets up to 6-311+G(d,p) and cc-PVDZ, the cis conformer is indicated as a transition state with all larger basis sets the cis conformer is the only stable form. The predicted energy difference from these calculations between the cis form and the higher energy trans conformer is about 125 cm(-1) which represents essentially the barrier to internal rotation of the NCS group (rotation around NC axis). Density functional theory calculation by the B3LYP method with the same basis sets predicts this barrier to be about 25 cm(-1). By utilizing the previously reported microwave rotational constants with the structural parameters predicted by the ab initio MP2(full)/6-311+G(d,p) calculations, adjusted r(0) structural parameters have been obtained for the cis form. The determined heavy atom parameters are: r(NC)=1.196(5), r(CS)=1.579(5), r(CN)=1.439(5), r(CC)=1.519(5)A for the distances and angles of angleCCN=112.1(5), angleCNC=146.2(5), angleNCS=174.0(5) degrees . The centrifugal distortion constants, dipole moments, conformational stability, vibrational frequencies, infrared intensities and Raman activities have been predicted from ab initio calculations and compared to experimental

Far infrared spectra of amorphous and crystalline water ice and changes in these phases as the result of proton irradiation

NASA Technical Reports Server (NTRS)

Hudson, Reggie L.; Moore, Marla H.

1992-01-01

Far infrared spectra from 20 microns (500 cm(sup -1)) to 100 microns (100 cm(sup -1)) of water ice were measured. Amorphous ice deposited at 13 K has one absorption band at 45 microns (220 cm(sup -1)). Amorphous ice evolves into a crystalline form with absorptions at 44 microns (229 cm(sup -1)) and 62 microns (162 cm(sup -1)) as the temperature is increased to 155 K. Spectra documenting this phase change are presented as well as spectra of crystalline ice at temperatures between 13 K and 155 K. Far infrared spectra of amorphous and crystalline water ice before and after proton irradiation are also presented. Changes in these two forms are discussed in relation to ices in comets, grains, and planetary satellites in various radiation environments. Observations of non-terrestrial clathrate hydrates are still lacking despite the fact that clathrates first were suggested to exist in cometary and interstellar ices over forty years ago. Spectroscopy, the most direct method of astronomical detection, has been hampered by the similarity of clathrate hydrate spectra to those of unenclathrated guest molecules and solid H2O. A methanol (CH3OH) clathrate hydrate, using a recently published procedure, was prepared and its far-IR spectrum investigated. The spectrum is quite differenct from that of either unenclathrated CH3OH or solid H2O and so should be of value in astronomical searches for this clathrate.

ALGORITHM BASED ON ARTIFICIAL BEE COLONY FOR UNFOLDING OF NEUTRON SPECTRA OBTAINED WITH BONNER SPHERES.

PubMed

Silva, Everton R; Freitas, Bruno M; Santos, Denison S; Maurício, Cláudia L P

2018-04-13

Occupational neutron fields usually have energies from the thermal range to some MeV and the characterization of the spectra is essential for estimation of the radioprotection quantities. Thus, the spectrum must be unfolded based on a limited number of measurements. This study implemented an algorithm based on the bee colonies behavior, named Artificial Bee Colony (ABC), where the intelligent behavior of the bees in search of food is reproduced to perform the unfolding of neutron spectra. The experimental measurements used Bonner spheres and 6LiI (Eu) detector, with irradiations using a thermal neutron flux and three reference fields: 241Am-Be, 252Cf and 252Cf (D2O). The ABC obtained good estimation of the expected spectrum even without previous information and its results were closer to expected spectra than those obtained by the SPUNIT algorithm.

Simplified method for the screening of technological maturity of red grape and total phenolic compounds of red grape skin: application of the characteristic vector method to near-infrared spectra.

PubMed

Nogales-Bueno, Julio; Ayala, Fernando; Hernández-Hierro, José Miguel; Rodríguez-Pulido, Francisco José; Echávarri, José Federico; Heredia, Francisco José

2015-05-06

Characteristic vector analysis has been applied to near-infrared spectra to extract the main spectral information from hyperspectral images. For this purpose, 3, 6, 9, and 12 characteristic vectors have been used to reconstruct the spectra, and root-mean-square errors (RMSEs) have been calculated to measure the differences between characteristic vector reconstructed spectra (CVRS) and hyperspectral imaging spectra (HIS). RMSE values obtained were 0.0049, 0.0018, 0.0012, and 0.0012 [log(1/R) units] for spectra allocated into the validation set, for 3, 6, 9, and 12 characteristic vectors, respectively. After that, calibration models have been developed and validated using the different groups of CVRS to predict skin total phenolic concentration, sugar concentration, titratable acidity, and pH by modified partial least-squares (MPLS) regression. The obtained results have been compared to those previously obtained from HIS. The models developed from the CVRS reconstructed from 12 characteristic vectors present similar values of coefficients of determination (RSQ) and standard errors of prediction (SEP) than the models developed from HIS. RSQ and SEP were 0.84 and 1.13 mg g(-1) of skin grape (expressed as gallic acid equivalents), 0.93 and 2.26 °Brix, 0.97 and 3.87 g L(-1) (expressed as tartaric acid equivalents), and 0.91 and 0.14 for skin total phenolic concentration, sugar concentration, titratable acidity, and pH, respectively, for the models developed from the CVRS reconstructed from 12 characteristic vectors.

Infrared spectra and crystal chemistry of scapolites: implications for Martian mineralogy

USGS Publications Warehouse

Swayze, G.A.; Clark, R.N.

1990-01-01

Near-infrared and midinfrared spectra of a wide range of scapolite compositions were studied to determine the cause of the 2.36-??m features that have been correlated with similar features in the near-IR spectrum of Mars. We attribute the 2.36-??m features to vibrations caused by HCO-3 and HSO-4 in the anion sites of scapolite. The 2.36-??m absorption complex consists of four overlapping bands. The relative intensities of all four bands vary according to the HCO-3/HSO-4 ratio and disordered anion site occupancy. The positional disorder of HCO-3 and HSO4 in the low-symmetry anion site of scapolite gives the 2.36-??m band complex a unique spectral signature not likely to be duplicated in any other mineral. -from Authors

Quantitative infrared and near-infrared gas-phase spectra for pyridine: Absolute intensities and vibrational assignments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, T. J.; Aker, P. M.; Scharko, N. K.

Using vetted methods for generating quantitative absorption reference data, broadband infrared and near-infrared spectra (total range 11,000 – 600 cm-1) of pyridine vapor were recorded at 0.1 cm-1 spectral resolution, with the analyte thermostatted at 298 K and pressure-broadened to 1 atmosphere using N2 ballast gas. The quantitative spectrum is reported for the first time, and we have re-assigned some of the 27 fundamental modes. Fundamental assignments were confirmed by IR vapor phase band shapes, FT-Raman measurements and comparison with previous analyses. For the 760-Torr vapor-phase IR data several bands show resolved peaks (Q-branches). We have also assigned for themore » first time hundreds of combination and overtone bands in the mid- and near-IR. All assignments were made via comparison to theoretically calculated frequencies and intensities: The frequencies were computed with Gaussian03 with the anharmonic option, using MP2 and the ccpvtz basis set. The intensities were taken from a VSCF calculation in GAMESS using Hartree-Fock (for overtones and combination bands) or from the harmonic MP2 for fundamentals. Overtone and combination band harmonic and anharmonic frequencies, as well as intensities were also calculated using the CFOUR program. It is seen in the NIR spectrum near 6000 cm-1 that the very strong bands arise from the C-H first overtones, whereas only much weaker bands are observed for combination bands of C-H stretching modes. Certain features are discussed for their potential utility for atmospheric monitoring.« less

Spectral calibration in the mid-infrared: Challenges and solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sloan, G. C.; Herter, T. L.; Houck, J. R.

2015-01-01

We present spectra obtained with the Infrared Spectrograph on the Spitzer Space Telescope of 33 K giants and 20 A dwarfs to assess their suitability as spectrophotometric standard stars. The K giants confirm previous findings that the strength of the SiO absorption band at 8 μm increases for both later optical spectral classes and redder (B–V){sub 0} colors, but with considerable scatter. For K giants, the synthetic spectra underpredict the strengths of the molecular bands from SiO and OH. For these reasons, the assumed true spectra for K giants should be based on the assumption that molecular band strengths inmore » the infrared can be predicted accurately from neither optical spectral class or color nor synthetric spectra. The OH bands in K giants grow stronger with cooler stellar temperatures, and they are stronger than predicted by synthetic spectra. As a group, A dwarfs are better behaved and more predictable than the K giants, but they are more likely to show red excesses from debris disks. No suitable A dwarfs were located in parts of the sky continuously observable from Spitzer, and with previous means of estimating the true spectra of K giants ruled out, it was necessary to use models of A dwarfs to calibrate spectra of K giants from observed spectral ratios of the two groups and then use the calibrated K giants as standards for the full database of infrared spectra from Spitzer. We also describe a lingering artifact that affects the spectra of faint blue sources at 24 μm.« less

First-principles calculations of phonons and Raman and infrared spectra in Cd-IV-N2 compounds

NASA Astrophysics Data System (ADS)

Lyu, Sai; Lambrecht, Walter R. L.

2018-05-01

A first-principles study of the phonons at the zone center in Cd-IV-N2 compounds is presented with IV = Si, Ge, Sn. The calculations are performed for the most likely Pbn21 crystal structure, after showing that it is indeed lower in total energy compared to the closely related Pmc21 structure. The normal mode frequencies are calculated using density functional perturbation theory and symmetry labeled. The longitudinal optical-transverse optical splittings are determined using the Born effective charges which are also reported. These are used to simulate polarized Raman spectra for different scattering configurations as well as the infrared absorption and reflection spectra. The mode frequencies are found to decrease from Si to Ge to Sn as group-IV cation. The spectra show a wide variety of number of prominent peaks and relative intensities in spite of the great similarities of these three materials. Phonon densities of states and their analysis in atom by atom contributions are also reported.

Predicting ambient aerosol Thermal Optical Reflectance (TOR) measurements from infrared spectra: elemental carbon

NASA Astrophysics Data System (ADS)

Dillner, A. M.; Takahama, S.

2015-06-01

Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as Thermal-Optical Reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier Transform Infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure tested and developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive, and non-destructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FTIR spectra are divided into calibration and test sets. Two calibrations are developed, one which is developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a~uniform distribution of low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the low EC calibration to low EC samples and the Uniform EC calibration to all other samples is used to produces predictions for low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of variation (R2; 0.96), no

Calibration and Vegetation Field Spectra Collection for the 2000 AVIRIS Hawaii Deployment

NASA Technical Reports Server (NTRS)

Dennison, Philip E.; Gardner, Margaret E.; Roberts, Dar A.; Green, Robert O.

2001-01-01

As part of the April 2000 Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Hawaii deployment, two researchers from the University of California, Santa Barbara, were sent to Hawaii to collect supporting field data. The primary goal of the fieldwork was to obtain spectra of bright targets to be used for retrieving surface reflectance from AVIRIS imagery. Secondary goals included recording the spectra of dominant vegetation, marking the position of homogeneous land cover for use as potential image endmembers (PIEs), and recording firsthand impressions of cover types. Primary and secondary goals were met. Spectra were recorded for 12 calibration targets on 5 islands and spectra were obtained for 61 vegetation species. Twenty PIEs were located, and video was used to document cover at 56 locations.

Removing interference-based effects from the infrared transflectance spectra of thin films on metallic substrates: a fast and wave optics conform solution.

PubMed

Mayerhöfer, Thomas G; Pahlow, Susanne; Hübner, Uwe; Popp, Jürgen

2018-06-25

A hybrid formalism combining elements from Kramers-Kronig based analyses and dispersion analysis was developed, which allows removing interference-based effects in the infrared spectra of layers on highly reflecting substrates. In order to enable a highly convenient application, the correction procedure is fully automatized and usually requires less than a minute with non-optimized software on a typical office PC. The formalism was tested with both synthetic and experimental spectra of poly(methyl methacrylate) on gold. The results confirmed the usefulness of the formalism: apparent peak ratios as well as the interference fringes in the original spectra were successfully corrected. Accordingly, the introduced formalism makes it possible to use inexpensive and robust highly reflecting substrates for routine infrared spectroscopic investigations of layers or films the thickness of which is limited by the imperative that reflectance absorbance must be smaller than about 1. For thicker films the formalism is still useful, but requires estimates for the optical constants.

500 days of SN 2013dy: spectra and photometry from the ultraviolet to the infrared

NASA Astrophysics Data System (ADS)

Pan, Y.-C.; Foley, R. J.; Kromer, M.; Fox, O. D.; Zheng, W.; Challis, P.; Clubb, K. I.; Filippenko, A. V.; Folatelli, G.; Graham, M. L.; Hillebrandt, W.; Kirshner, R. P.; Lee, W. H.; Pakmor, R.; Patat, F.; Phillips, M. M.; Pignata, G.; Röpke, F.; Seitenzahl, I.; Silverman, J. M.; Simon, J. D.; Sternberg, A.; Stritzinger, M. D.; Taubenberger, S.; Vinko, J.; Wheeler, J. C.

2015-10-01

SN 2013dy is a Type Ia supernova (SN Ia) for which we have compiled an extraordinary data set spanning from 0.1 to ˜ 500 d after explosion. We present 10 epochs of ultraviolet (UV) through near-infrared (NIR) spectra with Hubble Space Telescope/Space Telescope Imaging Spectrograph, 47 epochs of optical spectra (15 of them having high resolution), and more than 500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and slowly declining light curve (Δm15(B) = 0.92 mag), shallow Si II λ 6355 absorption, and a low velocity gradient. We detect strong C II in our earliest spectra, probing unburned progenitor material in the outermost layers of the SN ejecta, but this feature fades within a few days. The UV continuum of SN 2013dy, which is strongly affected by the metal abundance of the progenitor star, suggests that SN 2013dy had a relatively high-metallicity progenitor. Examining one of the largest single set of high-resolution spectra for an SN Ia, we find no evidence of variable absorption from circumstellar material. Combining our UV spectra, NIR photometry, and high-cadence optical photometry, we construct a bolometric light curve, showing that SN 2013dy had a maximum luminosity of 10.0^{+4.8}_{-3.8} × 10^{42} erg s-1. We compare the synthetic light curves and spectra of several models to SN 2013dy, finding that SN 2013dy is in good agreement with a solar-metallicity W7 model.

Near-Infrared Spectroscopy of Henan and Watsonia Family Asteroids

NASA Astrophysics Data System (ADS)

Bus, S. J.; Binzel, R. P.; Sunshine, J.; Burbine, T. H.; McCoy, T. J.

2002-09-01

We present visible and near-infrared spectra for members of both the Henan and Watsonia asteroid families. These two families are known to contain asteroids belonging to the taxonomic L class based on visible wavelength spectroscopy obtained during the second phase of the Small Main-belt Asteroid Spectroscopic Survey (SMASSII, Bus and Binzel 2002, Icarus in press). The L-type asteroids have visible-wavelength spectra similar to those of K-types but with steeper spectral slopes shortward of 0.75 micron, becoming relatively flat longward of 0.75 micron and showing little or no concave curvature related to a 1 micron silicon absorption band. Our current study of the Henan and Watsonia families uses data obtained with SpeX, a medium-resolution near-infrared spectrograph available at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. When combined with the SMASSII results, we find the near-infrared spectra of these asteroids contains very weak 1 micron bands but have moderately deep 2 micron bands. A possible interpretation of this anomalous spectral signature is the presence of spinel, suggested by Burbine et al. (1992, Meteoritics 27, 424) for the asteroids 387 Aquitania and 980 Anacostia, both likely members of the Watsonia family (Bus 1999, Ph.D. thesis). The work of Burbine et al. made use of combined ECAS and 52-color measurements covering the visible and near-IR wavelengths out to 2.5 microns. We can now use the high signal-to-noise data obtained with SpeX to more fully explore the mineralogy of the taxonomic L class and to search for evidence of mineralogical variations among the Henan and Watsonia asteroid family members.

Similarity analysis of spectra obtained via reflectance spectrometry in legal medicine.

PubMed

Belenki, Liudmila; Sterzik, Vera; Bohnert, Michael

2014-02-01

In the present study, a series of reflectance spectra of postmortem lividity, pallor, and putrefaction-affected skin for 195 investigated cases in the course of cooling down the corpse has been collected. The reflectance spectrometric measurements were stored together with their respective metadata in a MySQL database. The latter has been managed via a scientific information repository. We propose similarity measures and a criterion of similarity that capture similar spectra recorded at corpse skin. We systematically clustered reflectance spectra from the database as well as their metadata, such as case number, age, sex, skin temperature, duration of cooling, and postmortem time, with respect to the given criterion of similarity. Altogether, more than 500 reflectance spectra have been pairwisely compared. The measures that have been used to compare a pair of reflectance curve samples include the Euclidean distance between curves and the Euclidean distance between derivatives of the functions represented by the reflectance curves at the same wavelengths in the spectral range of visible light between 380 and 750 nm. For each case, using the recorded reflectance curves and the similarity criterion, the postmortem time interval during which a characteristic change in the shape of reflectance spectrum takes place is estimated. The latter is carried out via a software package composed of Java, Python, and MatLab scripts that query the MySQL database. We show that in legal medicine, matching and clustering of reflectance curves obtained by means of reflectance spectrometry with respect to a given criterion of similarity can be used to estimate the postmortem interval.

Even-odd alternation of near-infrared spectra of alkane-α,ω-diols in their solid states

NASA Astrophysics Data System (ADS)

Toyama, Yuta; Murakami, Kohei; Yoshimura, Norio; Takayanagi, Masao

2018-05-01

Even-odd alternation of the melting points of α,ω-disubstituted linear alkanes such as alkane-α,ω-diols, alkane-α,ω-dinitriles and α,ω-diaminoalkanes is well known. Melting points for compounds with an even number of carbons in their alkyl chains are systematically higher than those for compounds with an odd number of carbons. In order to clarify the origin of this alternation, near-infrared absorption spectra of linear alkane-α,ω-diols with 3 to 9 carbon atoms in their alkyl chains were measured in the liquid and solid states. The band due to the first overtone of the Osbnd H stretching mode was investigated. The temperature-dependent spectra of all alkane-α,ω-diols in their liquid states were found to be similar; no even-odd alternation was observed. In the solid state, however, spectra of alkane-α,ω-diols with even and odd numbers of carbon atoms differed greatly. Spectra of alkane-α,ω-diols with an odd number of carbon atoms in their solid states were similar to those in the liquid states, although the variation of spectra observed upon lowering the temperature of liquid seemed to continue when the liquids were frozen. In contrast, spectra of alkane-α,ω-diols with an even number of carbon atoms in their liquid and solid states were found to be quite different. New bands appeared upon freezing. The observed even-odd alternation of the spectra observed for alkane-α,ω-diols in their solid states is presumably caused by their even-odd alternation of crystal structures.

Infrared spectra of complex organic molecules in astronomically relevant ice matrices. I. Acetaldehyde, ethanol, and dimethyl ether

NASA Astrophysics Data System (ADS)

Terwisscha van Scheltinga, J.; Ligterink, N. F. W.; Boogert, A. C. A.; van Dishoeck, E. F.; Linnartz, H.

2018-03-01

Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking. Aim. This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations. Methods: Fourier transform transmission spectroscopy (500-4000 cm-1/20-2.5 μm, 1.0 cm-1 resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed. Results: We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 μm bands are recommended, for ethanol the 11.36 and 7.240 μm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 μm can be used. All spectra are publicly available in the Leiden Database for Ice.

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the Space Infrared Telescope Facility (SIRTF) waits for encapsulation. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

NASA Image and Video Library

2003-08-14

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the Space Infrared Telescope Facility (SIRTF) waits for encapsulation. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

Infrared Spectra of Polycyclic Aromatic Hydrocarbons: Nitrogen Substitution

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W.; Arnold, James O. (Technical Monitor)

1998-01-01

The B3LYP/4-31G approach is used to compute the harmonic frequencies of substituted naphthalene, anthracene, and their cations. The substitutions include cyano (CN), aminio (NH2), imino (NH), and replacement of a CH group by a nitrogen atom. All unique sites are considered, namely 1 and 2 for naphthalene and 1, 2, and 9 for an'tracene, except for the imino, where only 2-iminonaphthalene is studied. The IR spectra of these substituted species are compared with those of the unsubstituted molecules. The addition of a CN group does not significantly affect the spectra except to add the CN stretching frequency. Replacing a CH group by N has only a small effect on the IR spectra. The addition of the NH2 group dramatically affects the neutral spectra, giving it much of the character of the cation spectra. However, the neutral 2-irrinonaphthalene spectra looks more like that of naphthalene than like the 2-aminonaphthalene spectra.

Spectra of M Asteroids V1.0

NASA Astrophysics Data System (ADS)

Fornasier, S.; Clark, B. E.; Migliorini, A.; Ockert-Bell, M.

2011-08-01

This data set contains reduced composite visual and near-infrared spectra of thirty M-type asteroids, observed over the years 2004-2008 and presented in Fornasier et al. (2010). The spectra were taken with the Dolores and NICS instruments at the Telescopio Nationale Galileo (TNG) in La Palma, with the EMMI and SOFI instruments at the ESO New Technology Telescope (NTT) in Chile, and with the SPeX instrument at the Infrared Telescope Facility (IRTF) in Hawaii. The individual spectra from the various instruments used to produce the composite spectra are also included.

Laboratory microwave, millimeter wave and far-infrared spectra of dimethyl sulfide

NASA Astrophysics Data System (ADS)

Jabri, A.; Van, V.; Nguyen, H. V. L.; Mouhib, H.; Kwabia Tchana, F.; Manceron, L.; Stahl, W.; Kleiner, I.

2016-05-01

Context. Dimethyl sulfide, CH3SCH3 (DMS), is a nonrigid, sulfur-containing molecule whose astronomical detection is considered to be possible in the interstellar medium. Very accurate spectroscopic constants were obtained by a laboratory analysis of rotational microwave and millimeter wave spectra, as well as rotation-torsional far-infrared (FIR) spectra, which can be used to predict transition frequencies for a detection in interstellar sources. Aims: This work aims at the experimental study and theoretical analysis of the ground torsional state and ground torsional band ν15 of DMS in a large spectral range for astrophysical use. Methods: The microwave spectrum was measured in the frequency range 2-40 GHz using two Molecular Beam Fourier Transform MicroWave (MB-FTMW) spectrometers in Aachen, Germany. The millimeter spectrum was recorded in the 50-110 GHz range. The FIR spectrum was measured for the first time at high resolution using the FT spectrometer and the newly built cryogenic cell at the French synchrotron SOLEIL. Results: DMS has two equivalent methyl internal rotors with a barrier height of about 730 cm-1. We performed a fit, using the XIAM and BELGI-Cs-2Tops codes, that contained the new measurements and previous transitions reported in the literature for the ground torsional state νt = 0 (including the four torsional species AA, AE, EA and EE) and for the ground torsional band ν15 = 1 ← 0 (including only the AA species). In the microwave region, we analyzed 584 transitions with J ≤ 30 of the ground torsional state νt = 0 and 18 transitions with J ≤ 5 of the first excited torsional state νt = 1. In the FIR range, 578 transitions belonging to the torsional band ν15 = 1 ← 0 with J ≤ 27 were assigned. Totally, 1180 transitions were included in a global fit with 21 accurately determined parameters. These parameters can be used to produce a reliable line-list for an astrophysical detection of DMS. Full Tables B.1 and C.1, and Table E.1 are

KENNEDY SPACE CENTER, FLA. - A solid rocket booster (SRB) for the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF) is lifted off its transporter on Launch Complex 17-B, Cape Canaveral Air Force Station. The SRB will be added to the launch vehicle in the background. The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. SIRTF, consisting of three cryogenically cooled science instruments and an 0.85-meter telescope, 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. - A solid rocket booster (SRB) for the Delta II Heavy rocket that will launch the Space Infrared Telescope Facility (SIRTF) is lifted off its transporter on Launch Complex 17-B, Cape Canaveral Air Force Station. The SRB will be added to the launch vehicle in the background. The Delta II Heavy features nine 46-inch-diameter, stretched SRBs. SIRTF, consisting of three cryogenically cooled science instruments and an 0.85-meter telescope, 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.

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, wait for the Space Infrared Telescope Facility (SIRTF) to reach their level. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, wait for the Space Infrared Telescope Facility (SIRTF) to reach their level. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, watch as the Space Infrared Telescope Facility (SIRTF) clears the platform. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, watch as the Space Infrared Telescope Facility (SIRTF) clears the platform. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - After dawn, the Space Infrared Telescope Facility (SIRTF) is lifted up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - After dawn, the Space Infrared Telescope Facility (SIRTF) is lifted up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) is lowered into the opening of the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) is lowered into the opening of the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - Viewed from below, the Space Infrared Telescope Facility (SIRTF) is lifted up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Viewed from below, the Space Infrared Telescope Facility (SIRTF) is lifted up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

Infrared spectra of rotating protostars

NASA Technical Reports Server (NTRS)

Adams, F. C.; Shu, F. H.

1986-01-01

Earlier calculations of the infrared emission expected from stars in the process of being made are corrected to include the most important observable effects of rotation and generalized. An improved version of the spherical model of a previous paper is developed, and the corresponding emergent spectral energy distributions are calculated for the theoretically expected mass infall rate in the cores of cool and quiescent molecular clouds. The dust grain opacity model and the temperature profile parameterization are improved. It is shown that the infrared spectrum of the IRAS source 04264+2426, which is associated with a Herbig-Haro object, can be adequately represented in terms of a rotating and accreting protostar. This strengthens the suggestion that collimated outflows in young stellar objects originate when a stellar wind tries to emerge and reverse the swirling pattern of infall which gave birth to the central star.

Modeling of aircraft exhaust emissions and infrared spectra for remote measurement of nitrogen oxides

NASA Astrophysics Data System (ADS)

Beier, K.; Schreier, F.

1994-10-01

Infrared (IR) molecular spectroscopy is proposed to perform remote measurements of NOx concentrations in the exhaust plume and wake of aircraft. The computer model NIRATAM is applied to simulate the physical and chemical properties of the exhaust plume and to generate low resolution IR spectra and synthetical thermal images of the aircraft in its natural surroundings. High-resolution IR spectra of the plume, including atmospheric absorption and emission, are simulated using the molecular line-by-line radiation model FASCODE2. Simulated IR spectra of a Boeing 747-400 at cruising altitude for different axial and radial positions in the jet region of the exhaust plume are presented. A number of spectral lines of NO can be identified that can be discriminated from lines of other exhaust gases and the natural atmospheric background in the region around 5.2 µm. These lines can be used to determine NO concentration profiles in the plume. The possibility of measuring nitrogen dioxide NO2 is also discussed briefly, although measurements turn out to be substantially less likely than those of NO. This feasibility study compiles fundamental data for the optical and radiometric design of an airborne Fourier transform spectrometer and the preparation of in-flight measurements for monitoring of aircraft pollutants

Detection of atomic oxygen and further line assignments in the far-infrared stratospheric spectrum

NASA Technical Reports Server (NTRS)

Carli, B.; Mencaraglia, F.; Bonetti, A.; Carlotti, M.; Nolt, I.

1985-01-01

Recent progress in high-resolution measurement of sub-millimeter and far-infrared emission in the stratosphere is reviewed. Attention is given to the results of recent balloon measurements of the minor stratospheric constituents in the spectral range 40-190 per cm. Emission spectra are presented for HCl; HF; and OH. Emission spectra were also obtained for atomic oxygen; hydrobromic acid; and hydroperoxyl radical. The possibility of detecting HO2 and H2O2 in the far-infrared is also briefly discussed.

Very low H O H bending frequencies. IV. Fourier transform infrared spectra of synthetic dittmarite

NASA Astrophysics Data System (ADS)

Šoptrajanov, Bojan; Stefov, Viktor; Kuzmanovski, Igor; Jovanovski, Gligor; Lutz, H. Dieter; Engelen, Bernward

2002-08-01

The Fourier transform infrared spectra of MgNH 4PO 4·H 2O (the synthetic analogue of the mineral dittmarite) and of a series of its partially deuterated analogues have been studied as a part of our continuous work on compounds exhibiting very low water bending frequencies. Although, the presence of ammonium bands makes the assignments in this case more difficult than for the potassium analogues, the isomorphism between the compounds of the MNH 4PO 4·H 2O type (M=Mg, Co, Ni, Mn and one of the polymorphs of CdNH 4PO 4·H 2O) and those which contain potassium instead of ammonium as well as the careful analysis of the spectra warrant the conclusion that in the presently studied compound the water bending mode appears at a frequency which is far more than 100 cm -1 lower than in the gaseous water. The spectra clearly show that the ammonium ions in the structure are involved in quite strong hydrogen bonds, a characteristic which is a precondition for a material to behave as a protonic conductor.

Analysis of Atmospheric Trace Constituents from High Resolution Infrared Balloon-Borne and Ground-Based Solar Absorption Spectra

NASA Technical Reports Server (NTRS)

Goldman, A.; Murcray, F. J.; Rinsland, C. P.; Blatherwick, R. D.; Murcray, F. H.; Murcray, D. G.

1991-01-01

Recent results and ongoing studies of high resolution solar absorption spectra will be presented. The analysis of these spectra is aimed at the identification and quantification of trace constituents important in atmospheric chemistry of the stratosphere and upper troposphere. Analysis of balloon-borne and ground-based spectra obtained at 0.0025/ cm covering the 700-2200/ cm interval will be presented. Results from ground-based 0.02/ cm solar spectra, from several locations such as Denver, South Pole, M. Loa, and New Zealand will also be shown. The 0.0025/ cm spectra show many new spectroscopic features. The analysis of these spectra, along with corresponding laboratory spectra, improves the spectral line parameters, and thus the accuracy of trace constituents quantification. The combination of the recent balloon flights, with earlier flights data since 1978 at 0.02/ cm resolution, provides trends analysis of several stratospheric trace species. Results for COF2, F22, SF6, and other species will be presented. Analysis of several ground-based solar spectra provides trends for HCl, HF and other species. The retrieval methods used for total column density and altitude distribution for both ground-based and balloon-borne spectra will be presented. These are extended for the analysis of the ground-based spectra to be obtained by the high resolution interferometers of the Network for Detection of Stratospheric Change (NDSC). Progress or the University of Denver studies for the NDSC will be presented. This will include intercomparison of solar spectra and trace gases retrievals obtained from simultaneous scans by the high resolution (0.0025/ cm) interferometers of BRUKER and BOMEM.

Development of Single-Seed Near-Infrared Spectroscopic Predictions of Corn and Soybeans Constituents Using Bulk Teference Values and Mean Spectra

USDA-ARS?s Scientific Manuscript database

Near-Infrared reflectance spectroscopic prediction models were developed for common constituents of corn and soybeans using bulk reference values and mean spectra from single-seeds. The bulk reference model and a true single-seed model for soybean protein were compared to determine how well the bul...

Even-odd alternation of near-infrared spectra of alkane-α,ω-diols in their solid states.

PubMed

Toyama, Yuta; Murakami, Kohei; Yoshimura, Norio; Takayanagi, Masao

2018-05-15

Even-odd alternation of the melting points of α,ω-disubstituted linear alkanes such as alkane-α,ω-diols, alkane-α,ω-dinitriles and α,ω-diaminoalkanes is well known. Melting points for compounds with an even number of carbons in their alkyl chains are systematically higher than those for compounds with an odd number of carbons. In order to clarify the origin of this alternation, near-infrared absorption spectra of linear alkane-α,ω-diols with 3 to 9 carbon atoms in their alkyl chains were measured in the liquid and solid states. The band due to the first overtone of the OH stretching mode was investigated. The temperature-dependent spectra of all alkane-α,ω-diols in their liquid states were found to be similar; no even-odd alternation was observed. In the solid state, however, spectra of alkane-α,ω-diols with even and odd numbers of carbon atoms differed greatly. Spectra of alkane-α,ω-diols with an odd number of carbon atoms in their solid states were similar to those in the liquid states, although the variation of spectra observed upon lowering the temperature of liquid seemed to continue when the liquids were frozen. In contrast, spectra of alkane-α,ω-diols with an even number of carbon atoms in their liquid and solid states were found to be quite different. New bands appeared upon freezing. The observed even-odd alternation of the spectra observed for alkane-α,ω-diols in their solid states is presumably caused by their even-odd alternation of crystal structures. Copyright © 2018 Elsevier B.V. All rights reserved.

High infrared radiance glass-ceramics obtained from fly ash and titanium slag.

PubMed

Wang, Shuming; Liang, Kaiming

2007-11-01

A new glass-ceramic was synthesized by crystal growth from a homogenous glass obtained by melting a mixture of fly ash collected from a power plant in Hebei province of China, titanium slag collected from a titanium factory in Sichuan province of China, and MgCO(3) as an additive. According to the measurement results of differential thermal analysis, a thermal treatment of nucleating at 850 degrees C for 2h and crystallizing at 985 degrees C for 1.5h was used to obtain the crystallized glass. X-ray diffraction and scanning electron microscopy measurements showed that the main crystalline phase of this material was iron-ion substituted cordierite, (Mg,Fe)(2)Al(4)Si(5)O(18), which is homogeneously dispersed within the parent glass matrix. The infrared radiance and thermal expansion coefficient of this material have been examined, and the results demonstrate that this glass-ceramic material has potential for application in a wide range of infrared heating and drying materials.

Analysis of fingerprints features of infrared spectra of various processed products of Rhizoma Coptidis and their different extracts

NASA Astrophysics Data System (ADS)

Xu, Beilei; Zhang, Guijun; Xu, Changhua; Sun, Suqin

2015-09-01

Fourier transform infrared spectroscopy (FT-IR) associated with second derivative infrared spectroscopy (SD-IR) and two-dimensional correlation infrared spectroscopy (2D-IR) are employed to analyze various processed products and different extracts of Rhizoma Coptidis. There is a shift of the peak of 1641 cm-1 of raw Rhizoma Coptidis after processed, which drifts to lower wave number. Peaks at 1508, 1387, 1363, 1332, 1274 and 1234 cm-1 barely change in most samples, except an obvious enhancement of these peaks after processed, suggesting that processed Rhizoma Coptidis may have higher content of berberine than raw material, which is corresponding to the results of correlation coefficients analysis. There are some differences in the absorption peaks in the range of 1800-1000 cm-1 in the SD-IR spectra, which have better resolution, of different processed products. 2D-IR spectra, which elevate the resolution further, can present more differences among the products in the range of 1300-800 cm-1 and 1800-1300 cm-1. Analysis of aqueous, ethanol and petroleum ether extracts of various processed products proves that there are distinctive differences of all auto-peaks in shapes and intensities in all of them. With the advantages of high resolution, high speed and convenience, FT-IR combined with 2D-IR can quickly and precisely distinguish various processed products of Rhizoma Coptidis and can be applied to predict the tendency of transformation of the complicated chemical mixture systems under heat perturbation.

Signal-to-noise contribution of principal component loads in reconstructed near-infrared Raman tissue spectra.

PubMed

Grimbergen, M C M; van Swol, C F P; Kendall, C; Verdaasdonk, R M; Stone, N; Bosch, J L H R

2010-01-01

The overall quality of Raman spectra in the near-infrared region, where biological samples are often studied, has benefited from various improvements to optical instrumentation over the past decade. However, obtaining ample spectral quality for analysis is still challenging due to device requirements and short integration times required for (in vivo) clinical applications of Raman spectroscopy. Multivariate analytical methods, such as principal component analysis (PCA) and linear discriminant analysis (LDA), are routinely applied to Raman spectral datasets to develop classification models. Data compression is necessary prior to discriminant analysis to prevent or decrease the degree of over-fitting. The logical threshold for the selection of principal components (PCs) to be used in discriminant analysis is likely to be at a point before the PCs begin to introduce equivalent signal and noise and, hence, include no additional value. Assessment of the signal-to-noise ratio (SNR) at a certain peak or over a specific spectral region will depend on the sample measured. Therefore, the mean SNR over the whole spectral region (SNR(msr)) is determined in the original spectrum as well as for spectra reconstructed from an increasing number of principal components. This paper introduces a method of assessing the influence of signal and noise from individual PC loads and indicates a method of selection of PCs for LDA. To evaluate this method, two data sets with different SNRs were used. The sets were obtained with the same Raman system and the same measurement parameters on bladder tissue collected during white light cystoscopy (set A) and fluorescence-guided cystoscopy (set B). This method shows that the mean SNR over the spectral range in the original Raman spectra of these two data sets is related to the signal and noise contribution of principal component loads. The difference in mean SNR over the spectral range can also be appreciated since fewer principal components can

Visible and infrared reflectance imaging spectroscopy of paintings: pigment mapping and improved infrared reflectography

NASA Astrophysics Data System (ADS)

Delaney, John K.; Zeibel, Jason G.; Thoury, Mathieu; Littleton, Roy; Morales, Kathryn M.; Palmer, Michael; de la Rie, E. René

2009-07-01

Reflectance imaging spectroscopy, the collection of images in narrow spectral bands, has been developed for remote sensing of the Earth. In this paper we present findings on the use of imaging spectroscopy to identify and map artist pigments as well as to improve the visualization of preparatory sketches. Two novel hyperspectral cameras, one operating from the visible to near-infrared (VNIR) and the other in the shortwave infrared (SWIR), have been used to collect diffuse reflectance spectral image cubes on a variety of paintings. The resulting image cubes (VNIR 417 to 973 nm, 240 bands, and SWIR 970 to 1650 nm, 85 bands) were calibrated to reflectance and the resulting spectra compared with results from a fiber optics reflectance spectrometer (350 to 2500 nm). The results show good agreement between the spectra acquired with the hyperspectral cameras and those from the fiber reflectance spectrometer. For example, the primary blue pigments and their distribution in Picasso's Harlequin Musician (1924) are identified from the reflectance spectra and agree with results from X-ray fluorescence data and dispersed sample analysis. False color infrared reflectograms, obtained from the SWIR hyperspectral images, of extensively reworked paintings such as Picasso's The Tragedy (1903) are found to give improved visualization of changes made by the artist. These results show that including the NIR and SWIR spectral regions along with the visible provides for a more robust identification and mapping of artist pigments than using visible imaging spectroscopy alone.

Infrared Spectra and Optical Constants of Astronomical Ices: I. Amorphous and Crystalline Acetylene

NASA Technical Reports Server (NTRS)

Hudson, R. L.; Ferrante, R. F.; Moore, M. H.

2013-01-01

Here we report recent measurements on acetylene (C2H2) ices at temperatures applicable to the outer Solar System and the interstellar medium. New near- and mid-infrared data, including optical constants (n, k), absorption coefficients (alpha), and absolute band strengths (A), are presented for both amorphous and crystalline phases of C2H2 that exist below 70 K. Comparisons are made to earlier work. Electronic versions of the data are made available, as is a computer routine to use our reported n and k values to simulate the observed IR spectra. Suggestions are given for the use of the data and a comparison to a spectrum of Makemake is made.

Dielectric constant and low-frequency infrared spectra for liquid water and ice Ih within the E3B model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, L.; Ni, Y.; Drews, S. E. P.

2014-08-28

Two intrinsic difficulties in modeling condensed-phase water with conventional rigid non-polarizable water models are: reproducing the static dielectric constants for liquid water and ice Ih, and generating the peak at about 200 cm{sup −1} in the low-frequency infrared spectrum for liquid water. The primary physical reason for these failures is believed to be the missing polarization effect in these models, and consequently various sophisticated polarizable water models have been developed. However, in this work we pursue a different strategy and propose a simple empirical scheme to include the polarization effect only on the dipole surface (without modifying a model's intermolecularmore » interaction potential). We implement this strategy for our explicit three-body (E3B) model. Our calculated static dielectric constants and low-frequency infrared spectra are in good agreement with experiment for both liquid water and ice Ih over wide temperature ranges, albeit with one fitting parameter for each phase. The success of our modeling also suggests that thermal fluctuations about local minima and the energy differences between different proton-disordered configurations play minor roles in the static dielectric constant of ice Ih. Our analysis shows that the polarization effect is important in resolving the two difficulties mentioned above and sheds some light on the origin of several features in the low-frequency infrared spectra for liquid water and ice Ih.« less

Dielectric constant and low-frequency infrared spectra for liquid water and ice Ih within the E3B model.

PubMed

Shi, L; Ni, Y; Drews, S E P; Skinner, J L

2014-08-28

Two intrinsic difficulties in modeling condensed-phase water with conventional rigid non-polarizable water models are: reproducing the static dielectric constants for liquid water and ice Ih, and generating the peak at about 200 cm(-1) in the low-frequency infrared spectrum for liquid water. The primary physical reason for these failures is believed to be the missing polarization effect in these models, and consequently various sophisticated polarizable water models have been developed. However, in this work we pursue a different strategy and propose a simple empirical scheme to include the polarization effect only on the dipole surface (without modifying a model's intermolecular interaction potential). We implement this strategy for our explicit three-body (E3B) model. Our calculated static dielectric constants and low-frequency infrared spectra are in good agreement with experiment for both liquid water and ice Ih over wide temperature ranges, albeit with one fitting parameter for each phase. The success of our modeling also suggests that thermal fluctuations about local minima and the energy differences between different proton-disordered configurations play minor roles in the static dielectric constant of ice Ih. Our analysis shows that the polarization effect is important in resolving the two difficulties mentioned above and sheds some light on the origin of several features in the low-frequency infrared spectra for liquid water and ice Ih.

Comparison of three chemometrics methods for near-infrared spectra of glucose in the whole blood

NASA Astrophysics Data System (ADS)

Zhang, Hongyan; Ding, Dong; Li, Xin; Chen, Yu; Tang, Yuguo

2005-01-01

Principal Component Regression (PCR), Partial Least Square (PLS) and Artificial Neural Networks (ANN) methods are used in the analysis for the near infrared (NIR) spectra of glucose in the whole blood. The calibration model is built up in the spectrum band where there are the glucose has much more spectral absorption than the water, fat, and protein with these methods and the correlation coefficients of the model are showed in this paper. Comparing these results, a suitable method to analyze the glucose NIR spectrum in the whole blood is found.

Heavy Ozone Enrichments from ATMOS Infrared Solar Spectra

NASA Technical Reports Server (NTRS)

Irion, F. W.; Gunson, M. R.; Rinsland, C. P.; Yung, Y. L.; Abrams, M. C.; Chang, A. Y.; Goldman, A.

1996-01-01

Vertical enrichment profiles of stratospheric O-16O-16O-18 and O-16O-18O-16 (hereafter referred to as (668)O3 and (686)O3 respectively) have been derived from space-based solar occultation spectra recorded at 0.01 cm(exp-1) resolution by the ATMOS (Atmospheric Trace MOlecule Spectroscopy) Fourier transform infrared (FTIR) spectrometer. The observations, made during the Spacelab 3 and ATLAS-1, -2, and -3 shuttle missions, cover polar, mid-latitude and tropical regions between 26 to 2.6 mb inclusive (approximately 25 to 41 km). Average enrichments, weighted by molecular (48)O3 density, of (15 +/- 6)% were found for (668)O3 and (10 +/- 7)% for (686)O3. Defining the mixing ratio of (50)O3 as the sum of those for (668)O3 and (686)O3, an enrichment of (13 plus or minus 5)% was found for (50)O3 (1 sigma standard deviation). No latitudinal or vertical gradients were found outside this standard deviation. From a series of ground-based measurements by the ATMOS instrument at Table Mountain, California (34.4 deg N), an average total column (668)O3 enrichment of (17 +/- 4)% (1 sigma standard deviation) was determined, with no significant seasonal variation discernable. Possible biases in the spectral intensities that affect the determination of absolute enrichments are discussed.

Stratospheric NO and NO2 profiles at sunset from analysis of high-resolution balloon-borne infrared solar absorption spectra obtained at 33 deg N and calculations with a time-dependent photochemical model

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Boughner, R. E.; Larsen, J. C.; Goldman, A.; Murcray, F. J.; Murcray, D. G.

1984-01-01

Simultaneous stratospheric vertical profiles of NO and NO2 at sunset were derived from an analysis of infrared solar absorption spectra recorded from a float altitude of 33 km with an interferometer system during a balloon flight. A nonlinear least squares procedure was used to analyze the spectral data in regions of absorption by NO and NO2 lines. Normalized factors, determined from calculations of time dependent altitude profiles with a detailed photochemical model, were included in the onion peeling analysis to correct for the rapid diurnal changes in NO and NO2 concentrations with time near sunset. The CO2 profile was also derived from the analysis and is reported.

Thermal Infrared Spectra of a Suite of Forsterite Samples and Ab-initio Modelling of theirs Spectra

NASA Astrophysics Data System (ADS)

Maturilli, A.; Stangarone, C.; Helbert, J.; Tribaudino, M.; Prencipe, M.

2017-12-01

already observed (Helbert et al. 2013), this study wants to point out the main spectral features due to the composition and temperature. Our results are used to create a theoretical background to interpret the high temperature infrared emissivity spectra from MERTIS onboard the ESA BepiColombo mission to Mercury (Helbert et al. 2010).

Near-field effect in the infrared range through periodic Germanium subwavelength arrays.

PubMed

Dong, Wei; Hirohata, Toru; Nakajima, Kazutoshi; Wang, Xiaoping

2013-11-04

Using finite-difference-time-domain simulation, we have studied the near-field effect of Germanium (Ge) subwavelength arrays designed in-plane with a normal incidence. Spectra of vertical electric field component normal to the surface show pronounced resonance peaks in an infrared range, which can be applied in a quantum well infrared photodetector. Unlike the near-field optics in metallic systems that are commonly related to surface plasmons, the intense vertical field along the surface of the Ge film can be interpreted as a combination of diffraction and waveguide theory. The existence of the enhanced field is confirmed by measuring the Fourier transform infrared spectra of fabricated samples. The positions of the resonant peaks obtained in experiment are in good agreement with our simulations.

Infrared spectra of CO2-doped hydrogen clusters, (H2)N-CO2.

PubMed

McKellar, A R W

2012-03-07

Clusters of para-H(2) and/or ortho-H(2) containing a single carbon dioxide molecule are studied by high resolution infrared spectroscopy in the 2300 cm(-1) region of the CO(2) ν(3) fundamental band. The (H(2))(N)-CO(2) clusters are formed in a pulsed supersonic jet expansion from a cooled nozzle and probed using a rapid scan tunable diode laser. Simple symmetric rotor type spectra are observed with little or no resolved K-structure, and prominent Q-branch features for ortho-H(2) but not para-H(2). Observed rotational constants and vibrational shifts are reported for ortho-H(2) up to N = 7 and para-H(2) up to N = 15, with the N > 7 assignments only made possible with the help of theoretical simulations. The para-H(2) cluster with N = 12 shows clear evidence for superfluid effects, in good agreement with theory. The presence of larger clusters with N > 15 is evident in the spectra, but specific assignments are not possible. Mixed para- + ortho-H(2) cluster transitions are well predicted by linear interpolation between corresponding pure cluster line positions. © 2012 American Institute of Physics

In-situ infrared spectra of OH in rutile up to 1000 °C

NASA Astrophysics Data System (ADS)

Guo, Haihao

2017-09-01

The infrared spectra of hydrous, oriented single crystals of synthetic Al-doped and pure rutile were measured from room temperature to 1000 °C at 1 bar using a heating stage. At room temperature, the spectra show only one band at 3278 cm-1 in pure rutile, and two additional bands at 3303 and 3323 cm-1 in Al-doped rutile. The main band associated with Al at 3323 cm-1 loses intensity as temperature increases and nearly disappears already at 300 °C. This suggests that the corresponding defect only forms during cooling and, therefore, water speciation in rutile at room temperature is not representative of subduction zone or upper mantle conditions. All OH bands shift to lower wavenumbers at elevated temperatures with dν/d T = -0.0831 cm-1 K-1 for the main band at 3278 cm-1. This strong low-frequency shift is unexpected for an OH bond involved in hydrogen bonding, indicating decreasing O-O distance for the OH band. Together with the extreme broadening of the band at high temperature, it suggests some weakening of the OH bond strength and a rapid exchange of protons, consistent with rapid hydrogen diffusion in rutile.

The Ca II infrared triplet's performance as an activity indicator compared to Ca II H and K. Empirical relations to convert Ca II infrared triplet measurements to common activity indices

NASA Astrophysics Data System (ADS)

Martin, J.; Fuhrmeister, B.; Mittag, M.; Schmidt, T. O. B.; Hempelmann, A.; González-Pérez, J. N.; Schmitt, J. H. M. M.

2017-09-01

Aims: A large number of Calcium infrared triplet (IRT) spectra are expected from the Gaia and CARMENES missions. Conversion of these spectra into known activity indicators will allow analysis of their temporal evolution to a better degree. We set out to find such a conversion formula and to determine its robustness. Methods: We have compared 2274 Ca II IRT spectra of active main-sequence F to K stars taken by the TIGRE telescope with those of inactive stars of the same spectral type. After normalizing and applying rotational broadening, we subtracted the comparison spectra to find the chromospheric excess flux caused by activity. We obtained the total excess flux, and compared it to established activity indices derived from the Ca II H and K lines, the spectra of which were obtained simultaneously to the infrared spectra. Results: The excess flux in the Ca II IRT is found to correlate well with R'HK and R+HK, as well as SMWO, if the B - V-dependency is taken into account. We find an empirical conversion formula to calculate the corresponding value of one activity indicator from the measurement of another, by comparing groups of datapoints of stars with similar B - V.

Near-Infrared Scintillation of Liquid Argon: Recent Results Obtained with the NIR Facility at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escobar, C. O.; Rubinov, P.; Tilly, E.

After a short review of previous attempts to observe and measure the near-infrared scintillation in liquid argon, we present new results obtained with NIR, a dedicated cryostat at the Fermilab Proton Assembly Building (PAB). The new results give confidence that the near-infrared light can be used as the much needed light signal in large liquid argon time projection chambers.11 pages,

Far-infrared spectra of yttrium-doped gold clusters Au(n)Y (n=1-9).

PubMed

Lin, Ling; Claes, Pieterjan; Gruene, Philipp; Meijer, Gerard; Fielicke, André; Nguyen, Minh Tho; Lievens, Peter

2010-06-21

The geometric, spectroscopic, and electronic properties of neutral yttrium-doped gold clusters Au(n)Y (n=1-9) are studied by far-infrared multiple photon dissociation (FIR-MPD) spectroscopy and quantum chemical calculations. Comparison of the observed and calculated vibrational spectra allows the structures of the isomers present in the molecular beam to be determined. Most of the isomers for which the IR spectra agree best with experiment are calculated to be the energetically most stable ones. Attachment of xenon to the Au(n)Y cluster can cause changes in the IR spectra, which involve band shifts and band splittings. In some cases symmetry changes, as a result of the attachment of xenon atoms, were also observed. All the Au(n)Y clusters considered prefer a low spin state. In contrast to pure gold clusters, which exhibit exclusively planar lowest-energy structures for small sizes, several of the studied species are three-dimensional. This is particularly the case for Au(4)Y and Au(9)Y, while for some other sizes (n=5, 8) the 3D structures have an energy similar to that of their 2D counterparts. Several of the lowest-energy structures are quasi-2D, that is, slightly distorted from planar shapes. For all the studied species the Y atom prefers high coordination, which is different from other metal dopants in gold clusters.

Altered rock spectra in the visible and near infrared. [western Nevada

NASA Technical Reports Server (NTRS)

Hunt, G. R.; Ashley, R. P. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Visible and near-infrared (0.35 to 2.5 micron m) bidirectional reflection spectra recorded for a suite of well-characterized hydrothermally altered rock samples typically display well defined bands caused by both electronic and vibrational processes in the individual mineral constituents. Electronic transitions in the iron-bearing constituent minerals produce diagnostic minima near 0.43, 0.65, 0.85, and 0.93 micron m. Vibrational transitions in clay and water-bearing mineral constituents produce characteristic single or multiple features over limited spectral ranges near 1.4, 1.75, 1.9, 2.2, and 2.35 micron m. The most abundant feature-producing minerals present in these rocks are hematite, goethite, and alunite. Others frequently present are jarosite, kaolinite, potassium micas, pyrophyllite, montmorillonite, diaspore, and gypsum. The spectral region near 2.2 micron m is particularly important for detecting altered rocks by remote sensing.

Wavelet Analysis Used for Spectral Background Removal in the Determination of Glucose from Near-Infrared Single-Beam Spectra

PubMed Central

Wan, Boyong; Small, Gary W.

2010-01-01

Wavelet analysis is developed as a preprocessing tool for use in removing background information from near-infrared (near-IR) single-beam spectra before the construction of multivariate calibration models. Three data sets collected with three different near-IR spectrometers are investigated that involve the determination of physiological levels of glucose (1-30 mM) in a simulated biological matrix containing alanine, ascorbate, lactate, triacetin, and urea in phosphate buffer. A factorial design is employed to optimize the specific wavelet function used and the level of decomposition applied, in addition to the spectral range and number of latent variables associated with a partial least-squares calibration model. The prediction performance of the computed models is studied with separate data acquired after the collection of the calibration spectra. This evaluation includes one data set collected over a period of more than six months. Preprocessing with wavelet analysis is also compared to the calculation of second-derivative spectra. Over the three data sets evaluated, wavelet analysis is observed to produce better-performing calibration models, with improvements in concentration predictions on the order of 30% being realized relative to models based on either second-derivative spectra or spectra preprocessed with simple additive and multiplicative scaling correction. This methodology allows the construction of stable calibrations directly with single-beam spectra, thereby eliminating the need for the collection of a separate background or reference spectrum. PMID:21035604

The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Achterberg, R. K.; Vinatier, S.; Bézard, B.; Coustenis, A.; Irwin, P. G. J.; Teanby, N. A.; de Kok, R.; Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Flasar, F. M.

2008-06-01

We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12C/ 13C in any C 2 molecule on Titan, and the first measurement of 12CH 4/ 13CH 4 (non-deuterated) on Titan by remote sensing. Our spectra cover five widely-spaced latitudes, 65° S to 71° N and we have searched for both latitude variability of 12C/ 13C within a given species, and also for differences between the 12C/ 13C in the three gases. For CH 4 alone, we find C12/C13=76.6±2.7 (1- σ), essentially in agreement with the 12CH 4/ 13CH 4 measured by the Huygens Gas Chromatograph/Mass Spectrometer instrument (GCMS) [Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784]: 82.3±1.0, and also with measured values in H 13CN and 13CH 3D by CIRS at lower precision [Bézard, B., Nixon, C., Kleiner, I., Jennings, D., 2007. Icarus 191, 397-400; Vinatier, S., Bézard, B., Nixon, C., 2007. Icarus 191, 712-721]. For the C 2 species, we find C12/C13=84.8±3.2 in C 2H 2 and 89.8±7.3 in C 2H 6, a possible trend of increasingly value with molecular mass, although these values are both compatible with the Huygens GCMS value to within error bars. There are no convincing trends in latitude. Combining all fifteen measurements, we obtain a value of C12/C13=80.8±2.0, also compatible with GCMS. Therefore, the evidence is mounting that 12C/ 13C is some 8% lower on Titan than on the Earth (88.9, inorganic standard), and lower than typical for the outer planets ( 88±7 [Sada, P.V., McCabe, G.H., Bjoraker, G.L., Jennings, D.E., Reuter, D.C., 1996. Astrophys. J. 472, 903-907]). There is no current model for this enrichment, and we discuss several mechanisms that may be at work.

Optical and Infrared Spectral Features of Nova Canis Majoris 2018

NASA Astrophysics Data System (ADS)

Rudy, Richard; Mauerhan, Jon; Crawford, Kirk; Russell, Ray; Wiktorowicz, Sloane

2018-04-01

Optical and IR spectra from 0.47-2.5 microns (resolution: 5-30 angstroms) of Nova Canis Majoris (CBET 4499), were obtained 2018 April 21.14 (UT) with the Aerospace Corporation's 1.0 m telescope using its Visible and Infrared Imaging Spectrograph (VNIRIS).

Mid-infrared emission and Raman spectra analysis of Er(3+)-doped oxyfluorotellurite glasses.

PubMed

Chen, Fangze; Xu, Shaoqiong; Wei, Tao; Wang, Fengchao; Cai, Muzhi; Tian, Ying; Xu, Shiqing

2015-04-10

This paper reports on the spectroscopic and structural properties in Er(3+)-doped oxyfluorotellurite glasses. The compositional variation accounts for the evolutions of Raman spectra, Judd-Ofelt parameters, radiative properties, and fluorescent emission. It is found that, when maximum phonon energy changes slightly, phonon density plays a crucial role in quenching the 2.7 μm emission generated by the Er(3+):(4)I11/2→(4)I13/2 transition. The comparative low phonon density contributes strong 2.7 μm emission intensity. The high branching ratio (18.63%) and large emission cross section (0.95×10(-20)  cm(2)) demonstrate that oxyfluorotellurite glass contained with 50 mol.% TeO2 has potential application in the mid-infrared region laser.

Magnetic Properties and Moessbauer Spectra of Several Iron(III) Dicarboxylic Acid Complexes.

DTIC Science & Technology

1980-10-01

model CS-202 Displex Cryogenic refrigerator with a model APD-E temperature controller manufactured by Air Products and Chemicals , Inc ., Allentown, Pa...coupled tL a special, helium gas filled shroud, Model DMX-20, supplied by Air Products and Chemicals , Inc . Infrared spectra were obtained on a Beckman IR

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.

Survey of Material for an Infrared-Opaque Coating

NASA Technical Reports Server (NTRS)

Smith, Sheldon M.; Howitt, Richard V.

1986-01-01

More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained for a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising off-the-shelf binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective in reducing far-infrared reflectance; (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TiBr powder.

Survey of material for an infrared-opaque coating

NASA Technical Reports Server (NTRS)

Smith, Sheldon M.; Howitt, Richard V.

1986-01-01

More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained of a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising 'off-the-shelf' binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective reducing far-infrared reflectance; and (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TlBr powder.

Atlas of high resolution infrared spectra of carbon dioxide

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Benner, D. C.; Devi, V. M.; Ferry, P. S.; Sutton, C. H.; Richardson, D. J.

1984-01-01

An atlas of long-path room-temperature absorption spectra of carbon dioxide is presented for the spectral intervals 1830-2100 cm, 2395-2680 cm, and 3140-3235 cm. The spectral data were recorded at high signal to noise with the 0.01 cm resolution Fourier transform interferometer. The spectra were obtained with pressures between 1 and 10 Torr of CO2 and with total paths between 24 and 384 meters. A compilation of the measured line positions and the assignments derived from the analysis are presented. Of the 3336 lines in the atlas, 94 percent were identified as CO2 lines or as residual lines H2O and CO. Calculated positions are presented for the carbon dioxide lines; a total of 52 bands of C-12O2-16, C-13O2-16, C-12O-16O-18, C-12O-16O-17, and C-13O-16O18 were identified. The weakest carbon dioxide lines marked in the atlas have intensities of approximately 0.5 x 10 to the negative 26th power cm/molecule at room temperature.

Combined use of infrared and Raman spectra in the characterization of orthoclase under various hydrostatic pressures.

PubMed

Liu, Rui; Wang, Zhi-Hua; Xu, Qiang; Yu, Na; Cao, Miao-Cong

2014-02-01

Colorless and pink orthoclase from Balikun granite body, East Zhunger in Xinjiang, served as the samples for the research on hydrostatic pressure experiment. The in-situ hydrostatic pressure test for orthoclases was conducted at the room temperature and pressures from 100 to 600 MPa using cubic zirconia anvil cell, with quartz as pressure gauge. The water located in the orthoclases for the conditions of different hydrostatic pressures was characterized through the methods of Fourier transform infrared (FTIR) and Raman spectra. The results showed that there was a linear correlation between the shifting of Raman bands and hydrostatic pressure applied to the feldspar. All of vibration peaks of M-O structural groups in orthoclases, the bending vibration peaks of Si(Al(IV))-O-Si bond and tetrahedron groups of [SiO4] in Raman spectra shifted toward the higher frequency regularly, the drift distance is 2, 2.19 and less than 2 cm(-1) respectively. The spectra of FTIR suggested that there was more water in colorless orthoclases than the pink one under certain conditions of hydrostatic pressure. The intensity and integral area centered at 3420 cm(-1) in FTIR spectra increased with the rising of hydrostatic pressure. The integral area for colorless and pink feldspar in FTIR spectra rose from 120, 1383 cm(-1) under normal pressure to 1570, 2001 cm(-1) at 600 MPa respectively. The experimental results might indicate that the water in the earth crust could enter the orthoclases in certain condition of the aqueous confining pressure.

INFRARED SPECTROSCOPY: A TOOL FOR DETERMINATION OF THE DEGREE OF CONVERSION IN DENTAL COMPOSITES

PubMed Central

Moraes, Luciene Gonçalves Palmeira; Rocha, Renata Sanches Ferreira; Menegazzo, Lívia Maluf; de AraÚjo, Eudes Borges; Yukimitu, Keizo; Moraes, João Carlos Silos

2008-01-01

Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree. PMID:19089207

Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy.

PubMed

Xiong, Wei; Laaser, Jennifer E; Mehlenbacher, Randy D; Zanni, Martin T

2011-12-27

In the last ten years, two-dimensional infrared spectroscopy has become an important technique for studying molecular structures and dynamics. We report the implementation of heterodyne detected two-dimensional sum-frequency generation (HD 2D SFG) spectroscopy, which is the analog of 2D infrared (2D IR) spectroscopy, but is selective to noncentrosymmetric systems such as interfaces. We implement the technique using mid-IR pulse shaping, which enables rapid scanning, phase cycling, and automatic phasing. Absorptive spectra are obtained, that have the highest frequency resolution possible, from which we extract the rephasing and nonrephasing signals that are sometimes preferred. Using this technique, we measure the vibrational mode of CO adsorbed on a polycrystalline Pt surface. The 2D spectrum reveals a significant inhomogenous contribution to the spectral line shape, which is quantified by simulations. This observation indicates that the surface conformation and environment of CO molecules is more complicated than the simple "atop" configuration assumed in previous work. Our method can be straightforwardly incorporated into many existing SFG spectrometers. The technique enables one to quantify inhomogeneity, vibrational couplings, spectral diffusion, chemical exchange, and many other properties analogous to 2D IR spectroscopy, but specifically for interfaces.

Infrared Spectra of Hydrated Magnesium Salts and their Role in the Search for Possible Life Conditions on Jupiter Moons

NASA Technical Reports Server (NTRS)

Chaban, Galina; Huo, Winifred M.; Lee, Timothy J.; Kwak, Dochan (Technical Monitor)

2002-01-01

Recent observations from the Galileo satellite indicate that three of the Jupiter moons, Europa, Ganymede, and Callisto, may have subsurface oceans. Possible existence of such ocean and the nature of its composition are of great interest to astrobiologists. Data from Galileo's NIMS spectrometer indicate the possibility of hydrated salts on Europa's surface. To aid in the design of future missions, we investigated infrared spectra of MgSO4-nH20, n=1-3 using ab initio calculations. Geometry, energetics, dipole moments, vibrational frequencies and infrared intensities of pure and hydrated MgSO4 salts were determined. Significant differences are found between vibrational spectra of water molecules in complexes with MgSO4 and pure water. Some of the O-H stretching frequencies in the complexes are shifted to the red by up to 1,500 - 2,000 per cm. In addition, the SO2 stretching vibrations are found at lower frequency regions than the water vibrations. The calculated bands of water and SO2 fragments can serve as markers for the existence of the salt-water complexes on the surface of Jupiter's moon.

[Study of near infrared spectral preprocessing and wavelength selection methods for endometrial cancer tissue].

PubMed

Zhao, Li-Ting; Xiang, Yu-Hong; Dai, Yin-Mei; Zhang, Zhuo-Yong

2010-04-01

Near infrared spectroscopy was applied to measure the tissue slice of endometrial tissues for collecting the spectra. A total of 154 spectra were obtained from 154 samples. The number of normal, hyperplasia, and malignant samples was 36, 60, and 58, respectively. Original near infrared spectra are composed of many variables, for example, interference information including instrument errors and physical effects such as particle size and light scatter. In order to reduce these influences, original spectra data should be performed with different spectral preprocessing methods to compress variables and extract useful information. So the methods of spectral preprocessing and wavelength selection have played an important role in near infrared spectroscopy technique. In the present paper the raw spectra were processed using various preprocessing methods including first derivative, multiplication scatter correction, Savitzky-Golay first derivative algorithm, standard normal variate, smoothing, and moving-window median. Standard deviation was used to select the optimal spectral region of 4 000-6 000 cm(-1). Then principal component analysis was used for classification. Principal component analysis results showed that three types of samples could be discriminated completely and the accuracy almost achieved 100%. This study demonstrated that near infrared spectroscopy technology and chemometrics method could be a fast, efficient, and novel means to diagnose cancer. The proposed methods would be a promising and significant diagnosis technique of early stage cancer.

Ethylene Glycol - Polyethylene Glycol (EG-PEG) Mixtures: Infrared Spectra Wavelet Cross-Correlation Analysis.

PubMed

Caccamo, Maria Teresa; Magazù, Salvatore

2017-03-01

Infrared spectra were collected on mixtures of ethylene glycol (EG) and polyethylene glycol 600 (PEG600) as a function of weight fraction from pure EG to pure PEG600. In this paper, it will be shown that while the OH vibrational contribution drastically reduces its center frequency from 3450 cm -1 to 3300 cm -1 in the weight fraction range 0-25%, the displacement of the mixture spectral features of the mixtures from ideal behavior, i.e., in the absence of interaction, shows the presence of a non-ideal mixing process. Furthermore, wavelet cross-correlation analysis of the registered pairs of spectra and of the intramolecular O-H stretching contributions reveals how the addition of a small amount of pure EG to PEG600 dramatically influences the structural properties of the polymeric matrix, owing to an increase the intermolecular connectivity. In particular, the wavelet cross-correlation parameters, evaluated between each pair of the registered data as a function of weight fraction, in a linear-logarithmic plot, reveals an inflection point for a weight fraction of about 25% of EG, which confirms that, within the three-dimensional networks of hydrogen-bonded EG-PEG600 molecules, a key role is played by EG in determining an increase in the hydrogen-bond network density.

Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sivaraman, B.; Nair, B. G.; Mason, N. J.

2013-12-01

Following the recent report of the first identification of methyl acetate (CH{sub 3}COOCH{sub 3}) in the interstellar medium (ISM), we have carried out vacuum ultraviolet (VUV) and infrared (IR) spectroscopy studies on methyl acetate from 10 K until sublimation in an ultrahigh vacuum chamber simulating astrochemical conditions. We present the first VUV and IR spectra of methyl acetate relevant to ISM conditions. Spectral signatures clearly showed molecular reorientation to have started in the ice by annealing the amorphous ice formed at 10 K. An irreversible phase change from amorphous to crystalline methyl acetate ice was found to occur between 110more » K and 120 K.« less

Near-Infrared Spectroscopy of Himalia An Irregular Jovian Satellite

NASA Technical Reports Server (NTRS)

Brown, R. H.; Baines, K.; Bellucci, G.; Bibring, J.-P.; Buratti, B.; Capaccioni, F.; Cerroni, P.; Clark, R.; Coradini, A.; Cruikshank, D.

2002-01-01

Spectra of the irregular Jovian satellite Himalia were obtained with the Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini during the Jupiter Flyby on December 18-19, 2000. These are the first spectral data of an irregular satellite beyond 2.5 microns. Additional information is contained in the original extended abstract.

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, help guide the Space Infrared Telescope Facility (SIRTF) toward the opening in the foreground. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Workers on the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, help guide the Space Infrared Telescope Facility (SIRTF) toward the opening in the foreground. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) is rolled out of the hangar at Cape Canaveral Air Force Station during pre-dawn hours. It is being transported to Launch Pad 17-B where it will be lifted into the mobile service tower and prepared for launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - The Space Infrared Telescope Facility (SIRTF) is rolled out of the hangar at Cape Canaveral Air Force Station during pre-dawn hours. It is being transported to Launch Pad 17-B where it will be lifted into the mobile service tower and prepared for launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

KENNEDY SPACE CENTER, FLA. - Before dawn, the Space Infrared Telescope Facility (SIRTF) is attached to an overhead crane that will lift it up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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

2003-08-10

KENNEDY SPACE CENTER, FLA. - Before dawn, the Space Infrared Telescope Facility (SIRTF) is attached to an overhead crane that will lift it up the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station. SIRTF will be attached to the Delta II rocket and encapsulated in its fairing before launch. 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. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” 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.

Wavelet analysis used for spectral background removal in the determination of glucose from near-infrared single-beam spectra.

PubMed

Wan, Boyong; Small, Gary W

2010-11-29

Wavelet analysis is developed as a preprocessing tool for use in removing background information from near-infrared (near-IR) single-beam spectra before the construction of multivariate calibration models. Three data sets collected with three different near-IR spectrometers are investigated that involve the determination of physiological levels of glucose (1-30 mM) in a simulated biological matrix containing alanine, ascorbate, lactate, triacetin, and urea in phosphate buffer. A factorial design is employed to optimize the specific wavelet function used and the level of decomposition applied, in addition to the spectral range and number of latent variables associated with a partial least-squares calibration model. The prediction performance of the computed models is studied with separate data acquired after the collection of the calibration spectra. This evaluation includes one data set collected over a period of more than 6 months. Preprocessing with wavelet analysis is also compared to the calculation of second-derivative spectra. Over the three data sets evaluated, wavelet analysis is observed to produce better-performing calibration models, with improvements in concentration predictions on the order of 30% being realized relative to models based on either second-derivative spectra or spectra preprocessed with simple additive and multiplicative scaling correction. This methodology allows the construction of stable calibrations directly with single-beam spectra, thereby eliminating the need for the collection of a separate background or reference spectrum. Copyright © 2010 Elsevier B.V. All rights reserved.

Amplification of anharmonicities in multiphoton vibrational action spectra.

PubMed

Calvo, F; Parneix, P

2012-01-16

The influence of one or several infrared laser pulses on the stability of bare and argon-tagged sodium chloride clusters is investigated theoretically by a combination of computational methods involving explicit molecular dynamics and properly calibrated unimolecular rate theories. The fragmentation spectra obtained by varying the laser frequency in the far-IR range is compared to the linear absorption spectrum resulting from the dipole moment autocorrelation function. Under appropriate laser field parameters, the action spectra are found to resemble the absorption spectra quite accurately in terms of positions, line widths, and even relative intensities. However, the action spectra exhibit residual and systematic redshifts of a few percent, which are partly due to the finite spectral bandwidth but are amplified by the progressive heating by the laser. A quantitative analysis suggests that these anharmonicity effects should generally arise upon multiple photon absorption. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Infrared Measurements of Atmospheric Ethane (C2H6) From Aircraft and Ground-Based Solar Absorption Spectra in the 3000/ cm Region

NASA Technical Reports Server (NTRS)

Coffey, M. T.; Mankin, W. G.; Goldman, A.; Rinsland, C. P.; Harvey, G. A.; Devi, V. Malathy; Stokes, G. M.

1985-01-01

A number or prominent Q-branches or the upsilon(sub 7) band or C2H6 have been identified near 3000/ cm in aircraft and ground-based infrared solar absorption spectra. The aircraft spectra provide the column amount above 12 km at various altitudes. The column amount is strongly correlated with tropopause height and can be described by a constant mixing ratio of 0.46 ppbv in the upper troposphere and a mixing ratio scale height of 3.9 km above the tropopause. The, ground-based spectra yield a column of 9.0 x 10(exp 15) molecules/sq cm above 2.1 km; combining these results implies a tropospheric mixing ratio of approximately 0.63 ppbv.

Infrared measurements of atmospheric ethane (C2H6) from aircraft and ground-based solar absorption spectra in the 3000/cm region

NASA Technical Reports Server (NTRS)

Coffey, M. T.; Mankin, W. G.; Goldman, A.; Rinsland, C. P.; Harvey, G. A.; Devi, V. M.; Stokes, G. M.

1985-01-01

A number of prominent Q-branches of the nu-7 band of C2H6 have been identified near 3000/cm in aircraft and ground-based infrared solar absorption spectra. The aircraft spectra provide the column amount above 12 km at various altitudes. The column amount is strongly correlated with tropopause height and can be described by a constant mixing ratio of 0.46 ppbv in the upper troposphere and a mixing ratio scale height of 3.9 km above the tropopause. The ground-based spectra yield a column of 9.0 x 10 to the 15th molecules/sq cm above 2.1 km; combining these results implies a tropospheric mixing ratio of approximately 0.63 ppbv.

Infrared backscattering

NASA Technical Reports Server (NTRS)

Bohren, Craig F.; Nevitt, Timothy J.; Singham, Shermila Brito

1989-01-01

All particles in the atmosphere are not spherical. Moreover, the scattering properties of randomly oriented nonspherical particles are not equivalent to those of spherical particles no matter how the term equivalent is defined. This is especially true for scattering in the backward direction and at the infrared wavelengths at which some atmospheric particles have strong absorption bands. Thus calculations based on Mie theory of infrared backscattering by dry or insoluble atmospheric particles are suspect. To support this assertion, it was noted that peaks in laboratory-measured infrared backscattering spectra show appreciable shifts compared with those calculated using Mie theory. One example is ammonium sulfate. Some success was had in modeling backscattering spectra of ammonium sulfate particles using a simple statistical theory called the continuous distribution of ellipsoids (CDE) theory. In this theory, the scattering properties of an ensemble are calculated. Recently a modified version of this theory was applied to measured spectra of scattering by kaolin particles. The particles were platelike, so the probability distribution of ellipsoidal shapes was chosen to reflect this. As with ammonium sulfate, the wavelength of measured peak backscattering is shifted longward of that predicted by Mie theory.

DIRBE obtained at infrared wavelengths of 25, 60 and 100 Aum

NASA Technical Reports Server (NTRS)

2002-01-01

This image combines data from the DIRBE obtained at infrared wavelengths of 25, 60 and 100 Aum. The sky brightness at these wavelengths is represented respectively by blue, green, and red colors in the image. The plane of the Milky Way Galaxy lies horizontally across the middle of the image with the Galactic center at the center. The image is dominated by the thermal emission from interstellar dust in the Milky Way. The wispy-looking dust features are called 'infrared cirrus.' The structured, warmer emission from interplanetary dust, shown in blue, is also prominent. The image shows a number of well-known dusty regions in the Milky Way, such as the Orion molecular clouds (below the plane, far right) which are active 'stellar nurseries' in our Galaxy. Two neighboring galaxies, the Large and Small Magellanic Clouds also can be distinguished (below the plane, approximately halfway between the center and right edge of the image).

Influence of earlobe thickness on near infrared spectroscopy

NASA Astrophysics Data System (ADS)

Jiang, Jingying; Wang, Tianpei; Li, Si; Li, Lin; Liu, Jiajia; Xu, Kexin

2017-03-01

Near-infrared spectroscopy has been recognized as a potential technology for noninvasive blood glucose sensing. However, the detected spectral signal is unstable mainly because of (1) the weak light absorption of glucose itself within NIR range, (2) the influence of temperature and individual differences of biotissue. Our previous results demonstrated that the synergistic effect of both transmittance and reflectance could enhance the strength of the detection signal. In this talk, we design a set of experiments to analyze the effect of earlobe thickness on Near Infrared spectroscopic measurement by using home-made optical fiber probe within the wavelength of 1000-1600nm. Firstly, we made a MC simulation of single-layer skin model and five-layer skin model to get the diffused transmittance spectra and diffused reflectance spectra under different optaical path lengths. And then we obtain the spectra of the earlobes from different volunteers by the same way. The experimental results showed that with the increase of the thickness,the light intensity of diffused transmittance decreases, and the light intensity of diffused reflectance remaines substantially unchanged.

KENNEDY SPACE CENTER, FLA. - NASA's Space Infrared Telescope Facility (SIRTF) lifts off from Launch Pad 17-B, Cape Canaveral Air Force Station, on Aug. 25 at 1:35:39 a.m. EDT. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

NASA Image and Video Library

2003-08-25

KENNEDY SPACE CENTER, FLA. - NASA's Space Infrared Telescope Facility (SIRTF) lifts off from Launch Pad 17-B, Cape Canaveral Air Force Station, on Aug. 25 at 1:35:39 a.m. EDT. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the first half of the fairing is moved around the Space Infrared Telescope Facility (SIRTF). SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

NASA Image and Video Library

2003-08-14

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the first half of the fairing is moved around the Space Infrared Telescope Facility (SIRTF). SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the first half of the fairing (background) moves toward the Space Infrared Telescope Facility (foreground) for encapsulation. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

NASA Image and Video Library

2003-08-14

KENNEDY SPACE CENTER, FLA. - In the mobile service tower on Launch Pad 17-B, Cape Canaveral Air Force Station, the first half of the fairing (background) moves toward the Space Infrared Telescope Facility (foreground) for encapsulation. SIRTF will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space. Consisting of a 0.85-meter telescope and three cryogenically cooled science instruments, SIRTF will be the largest infrared telescope ever launched into space. It is the fourth and final element in NASA’s family of orbiting “Great Observatories.” Its highly sensitive instruments will give a unique view of the Universe and peer into regions of space that are hidden from optical telescopes.

The Rovibronic Spectra of the Cyclopentadienyl Radical

NASA Astrophysics Data System (ADS)

Sharma, Ketan; Miller, Terry A.; Stanton, John F.; Nesbitt, David

2017-06-01

Cyclopentadienyl (Cp) radical has been subject to numerous studies for the greater part of half a century. Experimental work has involved photo-electron spectroscopy, laser induced fluorescence excitation and emission, infrared absorption spectroscopy, and recently rotationally resolved spectra in the CH stretch region taken at JILA. Even more theoretical works appear in the literature, but substantial advances in computation have occurred since their completion. Cp's highly symmetric (D_{5h}) structure and doubly degenerate electronic ground (˜{X}^2E_1^{''}), which is subject to linear Jahn-Teller distortion, have been a great motivation for work on it. We have commenced new computational work to obtain a broad understanding of the electronic, vibrational, and rotational, i.e. rovibronic, structure of the Cp radical as revealed by its spectra, with particular emphasis on the new infrared spectra. The goal is to guide experiments and their analyses and reconcile results from spectroscopy and quantum chemistry calculations. T. Ichino, et al. J. Chem. Phys. 129, 084310 (2008) L. Yu, S. C. Foster, J. M. Williamson, M. C. Heaven and T. A. Miller J. Phys. Chem. 92, 4263 (1988) B. E. Applegate, A. J. Bezant and T. A. Miller J. Chem. Phys 114, 4869 (2001) D. Leicht, M. Kaufmann, G. Schwaab, and M. Havenith J. Chem. Phys. 145, 7 (2016), 074304.

Infrared Microtransmission And Microreflectance Of Biological Systems

NASA Astrophysics Data System (ADS)

Hill, Steve L.; Krishnan, K.; Powell, Jay R.

1989-12-01

The infrared microsampling technique has been successfully applied to a variety of biological systems. A microtomed tissue section may be prepared to permit both visual and infrared discrimination. Infrared structural information may be obtained for a single cell, and computer-enhanced images of tissue specimens may be calculated from spectral map data sets. An analysis of a tissue section anomaly may gg suest eitherprotein compositional differences or a localized concentration of foreign matterp. Opaque biological materials such as teeth, gallstones, and kidney stones may be analyzed by microreflectance spectroscop. Absorption anomalies due to specular dispersion are corrected with the Kraymers-Kronig transformation. Corrected microreflectance spectra may contribute to compositional analysis and correlate diseased-related spectral differences to visual specimen anomalies.

Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

NASA Technical Reports Server (NTRS)

Tiwari, S. N.; Manian, S. V. S.

1976-01-01

Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

Comparison of infrared and Raman wave numbers of neat molecular liquids: Which is the correct infrared wave number to use?

NASA Astrophysics Data System (ADS)

Bertie, John E.; Michaelian, Kirk H.

1998-10-01

This paper is concerned with the peak wave number of very strong absorption bands in infrared spectra of molecular liquids. It is well known that the peak wave number can differ depending on how the spectrum is measured. It can be different, for example, in a transmission spectrum and in an attenuated total reflection spectrum. This difference can be removed by transforming both spectra to the real, n, and imaginary, k, refractive index spectra, because both spectra yield the same k spectrum. However, the n and k spectra can be transformed to spectra of any other intensity quantity, and the peak wave numbers of strong bands may differ by up to 6 cm-1 in the spectra of the different quantities. The question which then arises is "which infrared peak wave number is the correct one to use in the comparison of infrared wave numbers of molecular liquids with wave numbers in other spectra?" For example, infrared wave numbers in the gas and liquid phase are compared to observe differences between the two phases. Of equal importance, the wave numbers of peaks in infrared and Raman spectra of liquids are compared to determine whether the infrared-active and Raman-active vibrations coincide, and thus are likely to be the same, or are distinct. This question is explored in this paper by presenting the experimental facts for different intensity quantities. The intensity quantities described are macroscopic properties of the liquid, specifically the absorbance, attenuated total reflectance, imaginary refractive index, k, imaginary dielectric constant, ɛ″, and molar absorption coefficient, Em, and one microscopic property of a molecule in the liquid, specifically the imaginary molar polarizability, αm″, which is calculated under the approximation of the Lorentz local field. The main experimental observations are presented for the strongest band in the infrared spectrum of each of the liquids methanol, chlorobenzene, dichloromethane, and acetone. Particular care was paid to

INFRARED MULTIPLE-PHOTON PHOTODISSOCIATION OF GAS-PHASE GROUP II METAL-NITRATE ANIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jos Oomens; Linda Myers; Ryan Dain

2008-06-01

Infrared spectra of gas-phase metal-nitrate anions M(NO3)3-, where M=Mg2+, Ca2+, Sr2+ and Ba2+, were recorded by infrared multiple photon dissociation (IRMPD) spectroscopy. Photodissociation of each of the precursors produces NO3- through the elimination of a neutral M(NO3)2 unit. An absorption pattern characteristic of metal nitrates is observed in the IRMPD spectra, including the symmetric and antisymmetric NO3 stretches. The latter is split into high and low frequency components as a result of perturbation of the nitrate symmetry by complexation to the metal ion, and the magnitude of the splitting decreases following the trend Mg2+ > Ca2+ > Sr2+ ? Ba2+.more » The experimental spectra are in good general agreement with those obtained from density functional theory calculations.« less

Reevaluation of lunar and Martian spectra in the mid-IR region.

PubMed

Plendl, J N; Plendl, H S

1982-12-15

A reference point method has been developed to correct infrared spectra from the moon and other celestial objects for selective absorption in the earth's atmosphere. The method is applied to lunar spectra that were obtained 2.3 km above sea level within the two atmospheric IR windows. The results indicate that SiO(2) and Al(2)O(3) are major mineral constituents in the four large surface areas analyzed in agreement with the localized probings at spacecraft landing sites. In addition, IR spectra from Martian dust clouds that were observed from the Mariner 9 spacecraft are examined. The principal sources of radiation in this case appear to be Al(2)O(3) and sulfur.

A consensus least squares support vector regression (LS-SVR) for analysis of near-infrared spectra of plant samples.

PubMed

Li, Yankun; Shao, Xueguang; Cai, Wensheng

2007-04-15

Consensus modeling of combining the results of multiple independent models to produce a single prediction avoids the instability of single model. Based on the principle of consensus modeling, a consensus least squares support vector regression (LS-SVR) method for calibrating the near-infrared (NIR) spectra was proposed. In the proposed approach, NIR spectra of plant samples were firstly preprocessed using discrete wavelet transform (DWT) for filtering the spectral background and noise, then, consensus LS-SVR technique was used for building the calibration model. With an optimization of the parameters involved in the modeling, a satisfied model was achieved for predicting the content of reducing sugar in plant samples. The predicted results show that consensus LS-SVR model is more robust and reliable than the conventional partial least squares (PLS) and LS-SVR methods.

Observations of silicate reststrahlen bands in lunar infrared spectra

NASA Technical Reports Server (NTRS)

Potter, A. E., Jr.; Morgan, T. H.

1982-01-01

Thermal emission spectra of three lunar sites (Apollo 11, Descartes Formation, and Tycho central peak) are measured in the 8-14 micron spectral range. Transmission and instrument effects are accounted for by forming ratios of the Descartes and Tycho spectra to the Apollo 11 spectrum. The ratio spectra are compared with ratios of published laboratory spectra of returned lunar samples and also with ratio spectra calculated using the Aronson-Emslie (1975) model. The comparisons show pyroxene bands in the Descartes ratio spectrum and plagioclase bands in the Tycho ratio spectrum. The Tycho spectrum is found to be consistent with the existence of fine plagioclase dust (approximately 1 micron) at the rock surface and a higher-than-usual sodium content of the plagioclase.

Reassignment of the Iron (3) Absorption Bands in the Spectra of Mars

NASA Technical Reports Server (NTRS)

Sherman, D. M.

1985-01-01

Absorption features in the near-infrared and visible region reflectance spectra of Mars have been assigned to specific Fe (3+) crystal-field and o(2-) yields Fe(3+) charge transfer transitions. Recently, near-ultraviolet absorption spectra of iron oxides were obtained and the energies of o(2-) yields Fe(3+) charge-transfer (LMCT) transitions were determined from accurate SCF-X # alpha-SW molecular orbital calculations on (FeO6)(9-) and (FeO4)(5-) clusters. Both the theoretical and experimental results, together with existing data in the literature, show that some of the previous Fe(3+) band assignments in the spectra of Mars need to be revised. The theory of Fe(3+) spectra in minerals is discussed and applied to the spectrum of Mars.

Additional spectra of asteroid 1996 FG3, backup target of the ESA MarcoPolo-R mission

NASA Astrophysics Data System (ADS)

de León, J.; Lorenzi, V.; Alí-Lagoa, V.; Licandro, J.; Pinilla-Alonso, N.; Campins, H.

2013-08-01

Context. Near-Earth binary asteroid (175706) 1996 FG3 is the current backup target of the ESA MarcoPolo-R mission, selected for the study phase of ESA M3 missions. It is a primitive (C-type) asteroid that shows significant variation in its visible and near-infrared spectra. Aims: Here we present new visible and near-infrared spectra of 1996 FG3. We compare our new data with other published spectra, analysing the variation in the spectral slope. The asteroid will not be observable again over the next three years at least. Methods: We obtained visible and near-infrared spectra using DOLORES and NICS instruments, respectively, at the Telescopio Nazionale Galileo (TNG), a 3.6 m telescope located at El Roque de los Muchachos Observatory in La Palma, Spain. To compare with other published spectra of the asteroid, we computed the spectral slope S', and studied any plausible correlation of this quantity with the phase angle (α). Results: In the case of visible spectra, we find a variation in spectral slope of ΔS' = 0.15 ± 0.10%/103 Å/° for 3°<α< 18°, which is in good agreement with the values found in the literature for the phase reddening effect. In the case of the near-infrared, there seems to be a trend between the reddening of the spectra and the phase angle, excluding one point. We find a variation in the slope of ΔS' = 0.04 ± 0.08%/103 Å/° for 6° < α < 51°. Our computed variation in S' is in good agreement with the only two values found in the literature for the phase reddening in the near-infrared. Conclusions: The variation in the spectral slope of asteroid 1996 FG3 shows a trend with the phase angle at the time of the observations, both in the visible and the near-infrared. It is worth noting that, to fully explain this spectral variability we should take into account other factors, like the position of the secondary component of the binary asteroid 1999 FG3 with respect to the primary, or the spin axis orientation at the time of the observations

Cosmic Infrared Background From Population III Stars and Its Effect on Spectra of High-z Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Kashlinsky, A.

2005-01-01

We discuss the contribution of Population III stars to the near-IR (NIR) cosmic infrared background (CIB) and its effect on spectra of high-z, high-energy gamma-ray bursts (GRBs) and other sources. It is shown that if Population III is composed of massive stars, the claimed NIR CIB excess will be reproduced if only approx. 4% plus or minus 2% of all baryons went through these stars. Regardless of the precise amount of the NIR CIB due to them, they likely left enough photons to provide a large optical depth for high-energy photons from distant GRBs. Observations of such GRBs are expected following the planned launch of NASA's GLAST mission. Detecting such damping in the spectra of high-z GRBs will then provide important information on the emissions from the Population III epoch, and the location of this cutoff may serve as an indicator of the GRBs' redshifts. We also point out the difficulty of unambiguously detecting the CIB part originating from Population III in spectra of low-z blazars.

On signatures of clouds in exoplanetary transit spectra

NASA Astrophysics Data System (ADS)

Pinhas, Arazi; Madhusudhan, Nikku

2017-11-01

Transmission spectra of exoplanetary atmospheres have been used to infer the presence of clouds/hazes. Such inferences are typically based on spectral slopes in the optical deviant from gaseous Rayleigh scattering or low-amplitude spectral features in the infrared. We investigate three observable metrics that could allow constraints on cloud properties from transmission spectra, namely the optical slope, the uniformity of this slope and condensate features in the infrared. We derive these metrics using model transmission spectra considering Mie extinction from a wide range of condensate species, particle sizes and scaleheights. First, we investigate possible degeneracies among the cloud properties for an observed slope. We find, for example, that spectra with very steep optical slopes suggest sulphide clouds (e.g. MnS, ZnS, Na2S) in the atmospheres. Secondly, (non)uniformities in optical slopes provide additional constraints on cloud properties, e.g. MnS, ZnS, TiO2 and Fe2O3 have significantly non-uniform slopes. Thirdly, infrared spectra provide an additional powerful probe into cloud properties, with SiO2, Fe2O3, Mg2SiO4 and MgSiO3 bearing strong infrared features observable with James Webb Space Telescope. We investigate observed spectra of eight hot Jupiters and discuss their implications. In particular, no single or composite condensate species considered here conforms to the steep and non-uniform optical slope observed for HD 189733b. Our work highlights the importance of the three above metrics to investigate cloud properties in exoplanetary atmospheres using high-precision transmission spectra and detailed cloud models. We make our Mie scattering data for condensates publicly available to the community.

Effects induced by gamma-irradiation and thermal treatment on the infrared spectra of ferrocene in its disordered state

NASA Astrophysics Data System (ADS)

Gaffar, M. A.; Abd-Elrahman, M. I.

2004-10-01

Lattice, rotation and intramolecular vibrations of ferrocene, Fe(C5H5)(2), crystallites of the C-2h(5) factor group in the disordered phase are calculated using the correlation theorem based on group theory. The correlation between the species of the C-1 site symmetry occupied by cyclopentadienyl molecules and those of the factor group C-2h, of the crystal are calculated. The number of lattice vibrations of the cyclopentadienyl molecules is found to be 12. with active modes in Raman and infrared (IR) spectra. The same number of rotations for the cyclopentadienyl molecules is expected to be allowed in both spectra. The active number of intramolecular vibrations for the cyclopentadienyl molecules having D-5 molecular symmetry is expected to be 80 vibrations in both the Raman and the IR spectra. The effect of gamma-irradiation with different doses and heat treatment at different temperatures on the IR spectra of ferrocene in the energy range 4000-200 cm(-1) is discussed. A number of bands continuously shifted their position, and a decrease in intensity with increasing gamma-dose is observed. New bands appeared in this spectral region for different annealing temperatures and different gamma-doses. These changes are discussed in terms of intermolecular interactions between molecules within the unit cell.

Determination of rock type on Mercury and the moon through remote sensing in the thermal infrared

NASA Technical Reports Server (NTRS)

Tyler, Ann L.; Kozlowski, Richard W. H.; Lebofsky, Larry A.

1988-01-01

Thermal infrared emission spectra of the moon and Mercury have been obtained using the Si:As photoconductor and circular variable filter at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. Lunar spectra from 7.2 to 12.2 microns for two different locations in the south polar highlands have Christiansen frequency peaks at 8.1 microns and 7.9 microns, respectively. This indicates different compositions at the two locations; mafic in the first case, more felsic in the second. Emission spectra from Mercury are not as spatially localized,; however, the longitude of maximum contribution to the spectrum can be calculated from thermal models of the earth-facing disk. Results for areas centered at two longitudes have been obtained. Two locations in the intercrater plains were observed. At 40-deg longitude (very near the crater Homer), a peak at 7.9 microns indicates mafic igneous rock type. Spectra emanating from 46-deg longitude have peaks at 7.8 microns, indicating a region borderline between mafic and intermediate composition.

Infrared Spectroscopy of Anhydrous Interplanetary Dust Particles

NASA Technical Reports Server (NTRS)

Keller, L. P.; Flynn, G. J.

2003-01-01

Infrared (IR) spectroscopy is the primary means of mineralogical analysis of materials outside our solar system. The identity and properties of circumstellar grains are inferred from spectral comparisons between astronomical observations and laboratory data from natural and synthetic materials. These comparisons have been facilitated by the Infrared Space Observatory (ISO), which obtained IR spectra from numerous astrophysical objects over a wide spectral range (out to 50/cm) where crystalline silicates and other phases have distinct features. The anhydrous interplanetary dust particles (IDPs) are particularly important comparison materials because some IDPs contain carbonaceous material with non-solar D/H and N-15/N-14 ratios and amorphous and crystalline silicates with non-solar 0- isotopic ratios, demonstrating that these IDPs contain preserved interstellar material. Here, we report on micro- Fourier transform (FT) IR spectrometry of IDPs, focusing on the inorganic components of primitive IDPs (FTIR spectra from the organic/carbonacecous materials in IDPs are described elsewhere).

Spectroscopic determination of leaf traits using infrared spectra

NASA Astrophysics Data System (ADS)

Buitrago, Maria F.; Groen, Thomas A.; Hecker, Christoph A.; Skidmore, Andrew K.

2018-07-01

Leaf traits characterise and differentiate single species but can also be used for monitoring vegetation structure and function. Conventional methods to measure leaf traits, especially at the molecular level (e.g. water, lignin and cellulose content), are expensive and time-consuming. Spectroscopic methods to estimate leaf traits can provide an alternative approach. In this study, we investigated high spectral resolution (6612 bands) emissivity measurements from the short to the long wave infrared (1.4-16.0 μm) of leaves from 19 different plant species ranging from herbaceous to woody, and from temperate to tropical types. At the same time, we measured 14 leaf traits to characterise a leaf, including chemical (e.g., leaf water content, nitrogen, cellulose) and physical features (e.g., leaf area and leaf thickness). We fitted partial least squares regression (PLSR) models across the SWIR, MWIR and LWIR for each leaf trait. Then, reduced models (PLSRred) were derived by iteratively reducing the number of bands in the model (using a modified Jackknife resampling method with a Martens and Martens uncertainty test) down to a few bands (4-10 bands) that contribute the most to the variation of the trait. Most leaf traits could be determined from infrared data with a moderate accuracy (65 < Rcv2 < 77% for observed versus predicted plots) based on PLSRred models, while the accuracy using the whole infrared range (6612 bands) presented higher accuracies, 74 < Rcv2 < 90%. Using the full SWIR range (1.4-2.5 μm) shows similarly high accuracies compared to the whole infrared. Leaf thickness, leaf water content, cellulose, lignin and stomata density are the traits that could be estimated most accurately from infrared data (with Rcv2 above 0.80 for the full range models). Leaf thickness, cellulose and lignin were predicted with reasonable accuracy from a combination of single infrared bands. Nevertheless, for all leaf traits, a combination of a few bands yields moderate to

The mid-infrared transmission spectra of Antarctic ureilites

NASA Technical Reports Server (NTRS)

Sandford, Scott A.

1993-01-01

The mid-IR (4000-450/cm; 2.5-22.2 microns) transmission spectra of seven Antarctic ureilites and 10 Antarctic H-5 ordinary chondrites are presented. The ureilite spectra show a number of absorption bands, the strongest of which is a wide, complex feature centered near 1000/cm (10 microns) due to Si-O stretching vibrations in silicates. The profiles and positions of the substructure in this feature indicate that Mg-rich olivines and pyroxenes are the main silicates responsible. The relative abundances of these two minerals, as inferred from the spectra, show substantial variation from meteorite to meteorite, but generally indicate olivine is the most abundant (olivine:pyroxene = 60:40 to 95:5). Both the predominance of olivine and the variable olivine-to-pyroxene ratio are consistent with the known composition and heterogeneity of ureilites. The H-5 ordinary chondrites spanned a range of weathering classes and were used to provide a means of addressing the extent to which the ureilite spectra may have been altered by weathering processes. It was found that, while weathering of these meteorites produces some weak bands due to the formation of small amounts of carbonates and hydrates, the profile of the main silicate feature has been little affected by Antarctic exposure in the meteorites studied here. The mid-IR ureilite spectra provide an additional means of testing potential asteroidal parent bodies for the ureilites.

High temperature crystal field spectra of transition metal-bearing minerals - Relevance to remote-sensed spectra of planetary surfaces

NASA Technical Reports Server (NTRS)

Parkin, K. M.; Burns, R. G.

1980-01-01

It is pointed out that transition metal ions in silicate minerals, glasses, and crystalline and amorphous oxyhydroxides and salts contribute to the visible-near infrared spectral profiles of planetary surfaces. Investigations are conducted to obtain spectral information which might be helpful in the interpretation of the remote-sensed spectra of planetary surfaces. A description is presented of the results of high temperature crystal field spectral measurements of a variety of heated minerals containing Cr(3+), Fe(3+), Fe(++), and Mn(++) ions in different coordination symmetries, taking into account a correlation of the temperature-induced variations with those previously observed for octahedrally coordinated Fe(++)-bearing silicates. The employed experimental methods are also discussed, giving attention to the preparation of the samples, the determination of the absorption spectra, electron microprobe analyses, and the curve fitting procedure.

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.

DISCOVERY OF RUBIDIUM, CADMIUM, AND GERMANIUM EMISSION LINES IN THE NEAR-INFRARED SPECTRA OF PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sterling, N. C.; Dinerstein, Harriet L.; Kaplan, Kyle F.

We identify [Rb iv] 1.5973 and [Cd iv] 1.7204 μm emission lines in high-resolution (R = 40,000) near-infrared spectra of the planetary nebulae (PNe) NGC 7027 and IC 5117, obtained with the Immersion GRating INfrared Spectrometer (IGRINS) on the 2.7 m telescope at McDonald Observatory. We also identify [Ge vi] 2.1930 μm in NGC 7027. Alternate identifications for these features are ruled out based on the absence of other multiplet members and/or transitions with the same upper levels. Ge, Rb, and Cd can be enriched in PNe by s-process nucleosynthesis during the asymptotic giant branch stage of evolution. To determine ionic abundances, we calculate [Rb iv] collision strengthsmore » and use approximations for those of [Cd iv] and [Ge vi]. Our identification of [Rb iv] 1.5973 μm is supported by the agreement between Rb{sup 3+}/H{sup +} abundances found from this line and the 5759.55 Å feature in NGC 7027. Elemental Rb, Cd, and Ge abundances are derived with ionization corrections based on similarities in ionization potential ranges between the detected ions and O and Ne ionization states. Our analysis indicates abundances 2–4 times solar for Rb and Cd in both nebulae. Ge is subsolar in NGC 7027, but its abundance is uncertain due to the large and uncertain ionization correction. The general consistency of the measured relative s-process enrichments with predictions from models appropriate for these PNe (2.0–2.5 M{sub ⊙}, [Fe/H] = −0.37) demonstrates the potential of using PN compositions to test s-process nucleosynthesis models.« less

Dual beam photoacoustic infrared spectroscopy of solids using an external cavity quantum cascade laser.

PubMed

Dehghany, M; Michaelian, K H

2012-06-01

Quantum cascade laser-based instrumentation for dual beam photoacoustic (PA) spectroscopy is described in this article. Experimental equipment includes a 4.55 μm (2141-2265 cm(-1)) continuous wave external cavity quantum cascade laser (EC-QCL), two gas-microphone PA cells, and two lock-in amplifiers. Correction for the time and wavenumber dependence of the laser output is effected through real-time division of the PA signals derived from the sample and reference channels. Source-compensated mid-infrared absorption spectra of carbon black powder and aromatic hydrocarbon solids were obtained to confirm the reliability of the method. Absorption maxima in the EC-QCL PA spectra of hydrocarbons are better defined than those in Fourier transform infrared spectra acquired under similar conditions, enabling the detection of several previously unknown bands.

Coherent backscattering effect in spectra of icy satellites and its modeling using multi-sphere T-matrix (MSTM) code for layers of particles

NASA Astrophysics Data System (ADS)

Pitman, Karly M.; Kolokolova, Ludmilla; Verbiscer, Anne J.; Mackowski, Daniel W.; Joseph, Emily C. S.

2017-12-01

The coherent backscattering effect (CBE), the constructive interference of light scattering in particulate surfaces (e.g., regolith), manifests as a non-linear increase in reflectance, or opposition surge, and a narrow negative polarization feature at small solar phase angles. Due to a strong dependence of the amplitude and angular width of this opposition surge on the absorptive characteristics of the surface material, CBE also produces phase-angle-dependent variations in the near-infrared spectra. In this paper we present a survey of such variations in the spectra of icy satellites of Saturn obtained by the Cassini spacecraft's Visual and Infrared Mapping Spectrometer (VIMS) and in the ground-based spectra of Oberon, a satellite of Uranus, obtained with TripleSpec, a cross-dispersed near-infrared spectrometer on the Astrophysical Research Consortium 3.5-m telescope located at the Apache Point Observatory near Sunspot, New Mexico. The paper also presents computer modeling of the saturnian satellite spectra and their phase-angle variations using the most recent version of the Multi-Sphere T-Matrix (MSTM) code developed to simulate light scattering by layers of randomly distributed spherical particles. The modeling allowed us not only to reproduce the observed effects but also to estimate characteristics of the icy particles that cover the surfaces of Rhea, Dione, and Tethys.

Far Infrared Measurements of Cirrus

NASA Technical Reports Server (NTRS)

Nolt, I. G.; Vanek, M. D.; Tappan, N. D.; Minnis, P.; Alltop, J. L.; Ade, A. R.; Lee, C.; Hamilton, P. A.; Evans, K. F.; Evans, A. H.

1999-01-01

Improved techniques for remote sensing of cirrus are needed to obtain global data for assessing the effect of cirrus in climate change models. Model calculations show that the far infrared/sub-millimeter spectral region is well suited for retrieving cirrus Ice Water Path and particle size parameters. Especially useful cirrus information is obtained at frequencies below 60 cm-1 where single particle scattering dominates over thermal emission for ice particles larger than about 50 m. Earth radiance spectra have been obtained for a range of cloud conditions using an aircraft-based Fourier transform spectrometer. The Far InfraRed Sensor for Cirrus (FIRSC) is a Martin-Puplett interferometer which incorporates a polarizer for the beamsplitter and can be operated in either intensity or linear polarization measurement mode. Two detector channels span 10 to 140 cm-1 with a spectral resolution of 0.1 cm-1; achieving a Noise Equivalent Temperature of approximately 1K at 30 cm-1 in a 4 sec scan. Examples are shown of measured and modeled Earth radiance for a range of cloud conditions from 1998 and 1999 flights.

Nondestructive estimation of wood chemical composition of sections of radial wood strips by diffuse reflectance near infrared spectroscopy

Treesearch

P. David Jones; Laurence R. Schimleck; Gary F. Peter; Richard F. Daniels; Alexander Clark

2006-01-01

The use of calibrated near infrared (NIR) spectroscopy for predicting the chemical composition of Pirus taeda L. (loblolly pine) wood samples is investigated. Seventeen P. taeda radial strips, representing seven different sites were selected and NlR spectra were obtained from the radial longitudinal face of each strip. The spectra...

Salts on Europa's surface detected by Galileo's near infrared mapping spectrometer

USGS Publications Warehouse

McCord, T.B.; Hansen, G.B.; Fanale, F.P.; Carlson, R.W.; Matson, D.L.; Johnson, T.V.; Smythe, W.D.; Crowley, J.K.; Martin, P.D.; Ocampo, A.; Hibbitts, C.A.; Granahan, J.C.

1998-01-01

Reflectance spectra in the 1- to 2.5-micrometer wavelength region of the surface of Europa obtained by Galileo's Near Infrared Mapping Spectrometer exhibit distorted water absorption bands that indicate the presence of hydrated minerals. The laboratory spectra of hydrated salt minerals such as magnesium sulfates and sodium carbonates and mixtures of these minerals provide a close match to the Europa spectra. The distorted bands are only observed in the optically darker areas of Europa, including the lineaments, and may represent evaporite deposits formed by water, rich in dissolved salts, reaching the surface from a water-rich layer underlying an ice crust.

An automated baseline correction protocol for infrared spectra of atmospheric aerosols collected on polytetrafluoroethylene (Teflon) filters

NASA Astrophysics Data System (ADS)

Kuzmiakova, Adele; Dillner, Ann M.; Takahama, Satoshi

2016-06-01

A growing body of research on statistical applications for characterization of atmospheric aerosol Fourier transform infrared (FT-IR) samples collected on polytetrafluoroethylene (PTFE) filters (e.g., Russell et al., 2011; Ruthenburg et al., 2014) and a rising interest in analyzing FT-IR samples collected by air quality monitoring networks call for an automated PTFE baseline correction solution. The existing polynomial technique (Takahama et al., 2013) is not scalable to a project with a large number of aerosol samples because it contains many parameters and requires expert intervention. Therefore, the question of how to develop an automated method for baseline correcting hundreds to thousands of ambient aerosol spectra given the variability in both environmental mixture composition and PTFE baselines remains. This study approaches the question by detailing the statistical protocol, which allows for the precise definition of analyte and background subregions, applies nonparametric smoothing splines to reproduce sample-specific PTFE variations, and integrates performance metrics from atmospheric aerosol and blank samples alike in the smoothing parameter selection. Referencing 794 atmospheric aerosol samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011, we start by identifying key FT-IR signal characteristics, such as non-negative absorbance or analyte segment transformation, to capture sample-specific transitions between background and analyte. While referring to qualitative properties of PTFE background, the goal of smoothing splines interpolation is to learn the baseline structure in the background region to predict the baseline structure in the analyte region. We then validate the model by comparing smoothing splines baseline-corrected spectra with uncorrected and polynomial baseline (PB)-corrected equivalents via three statistical applications: (1) clustering analysis, (2) functional group quantification

Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances

NASA Astrophysics Data System (ADS)

Banas, Krzysztof; Banas, Agnieszka M.; Heussler, Sascha P.; Breese, Mark B. H.

2018-01-01

In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment.

Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy

PubMed Central

Xiong, Wei; Laaser, Jennifer E.; Mehlenbacher, Randy D.; Zanni, Martin T.