NASA Technical Reports Server (NTRS)
Moore, Craig E.; Cardelino, Beatriz H.; Frazier, Donald O.; Niles, Julian; Wang, Xian-Qiang
1997-01-01
Calculations were performed on the valence contribution to the static molecular third-order polarizabilities (gamma) of thirty carbon-cage fullerenes (C60, C70, five isomers of C78, and twenty-three isomers of C84). The molecular structures were obtained from B3LYP/STO-3G calculations. The values of the tensor elements and an associated numerical uncertainty were obtained using the finite-field approach and polynomial expansions of orders four to eighteen of polarization versus static electric field data. The latter information was obtained from semiempirical calculations using the AM1 hamiltonian.
NASA Technical Reports Server (NTRS)
Moore, Craig E.; Cardelino, Beatriz H.; Frazier, Donald O.; Niles, Julian; Wang, Xian-Qiang
1997-01-01
Calculations were performed on the valence contribution to the static molecular third-order polarizabilities (gamma) of thirty carbon-cage fullerenes (C60, C70, five isomers of C78, and twenty-three isomers of C84). The molecular structures were obtained from B3LYP/STO-3G calculations. The values of the tensor elements and an associated numerical uncertainty were obtained using the finite-field approach and polynomial expansions of orders four to eighteen of polarization versus static electric field data. The latter information was obtained from semiempirical calculations using the AM1 hamiltonian.
NASA Technical Reports Server (NTRS)
Moore, C. E.; Cardelino, B. H.; Frazier, D. O.; Niles, J.; Wang, X.-Q.
1998-01-01
The static third-order polarizabilities (gamma) of C60, C70, five isomers of C78 and two isomers of C84 were analyzed in terms of three properties, from a geometric point of view: symmetry, aromaticity and size. The polarizability values were based on the finite field approximation using a semiempirical Hamiltonian (AM1) and applied to molecular structures obtained from density functional theory calculations. Symmetry was characterized by the molecular group order. The selection of 6-member rings as aromatic was determined from an analysis of bond lengths. Maximum interatomic distance and surface area were the parameters considered with respect to size. Based on triple linear regression analysis, it was found that the static linear polarizability (alpha) and gamma in these molecules respond differently to geometrical properties: alpha depends almost exclusively on surface area while gamma is affected by a combination of number of aromatic rings, length and group order, in decreasing importance. In the case of alpha, valence electron contributions provide the same information as all-electron estimates. For gamma, the best correlation coefficients are obtained when all-electron estimates are used and when the dependent parameter is ln(gamma) instead of gamma.
NASA Technical Reports Server (NTRS)
Moore, C. E.; Cardelino, B. H.; Frazier, D. O.; Niles, J.; Wang, X.-Q.
1998-01-01
The static third-order polarizabilities (gamma) of C60, C70, five isomers of C78 and two isomers of C84 were analyzed in terms of three properties, from a geometric point of view: symmetry, aromaticity and size. The polarizability values were based on the finite field approximation using a semiempirical Hamiltonian (AM1) and applied to molecular structures obtained from density functional theory calculations. Symmetry was characterized by the molecular group order. The selection of 6-member rings as aromatic was determined from an analysis of bond lengths. Maximum interatomic distance and surface area were the parameters considered with respect to size. Based on triple linear regression analysis, it was found that the static linear polarizability (alpha) and gamma in these molecules respond differently to geometrical properties: alpha depends almost exclusively on surface area while gamma is affected by a combination of number of aromatic rings, length and group order, in decreasing importance. In the case of alpha, valence electron contributions provide the same information as all-electron estimates. For gamma, the best correlation coefficients are obtained when all-electron estimates are used and when the dependent parameter is ln(gamma) instead of gamma.
Neipert, Christine; Space, Brian
2006-12-14
Sum vibrational frequency spectroscopy, a second order optical process, is interface specific in the dipole approximation. At charged interfaces, there exists a static field, and as a direct consequence, the experimentally detected signal is a combination of enhanced second and static field induced third order contributions. There is significant evidence in the literature of the importance/relative magnitude of this third order contribution, but no previous molecularly detailed approach existed to separately calculate the second and third order contributions. Thus, for the first time, a molecularly detailed time correlation function theory is derived here that allows for the second and third order contributions to sum frequency vibrational spectra to be individually determined. Further, a practical, molecular dynamics based, implementation procedure for the derived correlation functions that describe the third order phenomenon is also presented. This approach includes a novel generalization of point atomic polarizability models to calculate the hyperpolarizability of a molecular system. The full system hyperpolarizability appears in the time correlation functions responsible for third order contributions in the presence of a static field.
Decomposition of Polarimetric SAR Images Based on Second- and Third-order Statics Analysis
NASA Astrophysics Data System (ADS)
Kojima, S.; Hensley, S.
2012-12-01
There are many papers concerning the research of the decomposition of polerimetric SAR imagery. Most of them are based on second-order statics analysis that Freeman and Durden [1] suggested for the reflection symmetry condition that implies that the co-polarization and cross-polarization correlations are close to zero. Since then a number of improvements and enhancements have been proposed to better understand the underlying backscattering mechanisms present in polarimetric SAR images. For example, Yamaguchi et al. [2] added the helix component into Freeman's model and developed a 4 component scattering model for the non-reflection symmetry condition. In addition, Arii et al. [3] developed an adaptive model-based decomposition method that could estimate both the mean orientation angle and a degree of randomness for the canopy scattering for each pixel in a SAR image without the reflection symmetry condition. This purpose of this research is to develop a new decomposition method based on second- and third-order statics analysis to estimate the surface, dihedral, volume and helix scattering components from polarimetric SAR images without the specific assumptions concerning the model for the volume scattering. In addition, we evaluate this method by using both simulation and real UAVSAR data and compare this method with other methods. We express the volume scattering component using the wire formula and formulate the relationship equation between backscattering echo and each component such as the surface, dihedral, volume and helix via linearization based on second- and third-order statics. In third-order statics, we calculate the correlation of the correlation coefficients for each polerimetric data and get one new relationship equation to estimate each polarization component such as HH, VV and VH for the volume. As a result, the equation for the helix component in this method is the same formula as one in Yamaguchi's method. However, the equation for the volume
NASA Technical Reports Server (NTRS)
Pan, C.-L.; She, C.-Y.; Fairbank, W. M., Jr.; Billman, K. W.
1977-01-01
Effects of quantum mechanical interferences on third-order susceptibilities in molecules are studied. First principle calculations for molecular hydrogen are presented and shown to agree with results derived from experimental stimulated Raman gain and spontaneous Raman cross-section data. 10 percent third-harmonic conversion efficiency in H2 at 1 atm without phase matching should require a 150 MW per sq cm at 4.81 microns. As little as 5.9-MW power is sufficient when the beam is properly focused. Resonance Raman scattering (RRS) is proposed for experimentally investigating the interference effects, which tend to reduce the strength of third-order nonlinear susceptibilities.
Meng, Xiangru; Song, Yinglin; Hou, Hongwei; Fan, Yaoting; Li, Gang; Zhu, Yu
2003-02-24
Three novel coordination polymers [Pb(bbbm)(2)(NO(3))(2)](n) (bbbm = 1,1'-(1,4-butanediyl)bis-1H-benzimidazole) 1, [Zn(bbbt)(NCS)(2)](n) (bbbt = 1,1'-(1,4-butanediyl)bis-1H-benzotriazole) 2, and [Zn(pbbt)(NCS)(2)](n) (pbbt = 1,1'-(1,3-propylene)bis-1H-benzotriazole) 3 were synthesized and structurally characterized. Polymer 1 exhibits a two-dimensional rhombohedral grid network structure, the dimensions of the grid are 14.274 x 14.274 A, and the diagonal-to-diagonal distances are 24.809 x 14.125 A. Polymer 2 possesses a concavo-convex chain structure different from those of the known one-dimensional polymers, which are linear chain, zigzag chain, helical chain, double-stranded chain, and ladder chain. Polymer 3 exhibits a one-dimensional zigzag chain structure, and these chains were packed as an.ABAB. layered structure. The third-order nonlinear optical (NLO) properties of polymers1, 2, and 3 were determined with a 7-ns pulsed laser at 532 nm. 1 shows strong third-order NLO absorptive and refractive properties, and its alpha(2) and n(2) values were calculated to be 5.8 x 10(-)(9) m W(-)(1) and 4.67 x 10(-)(18) m(2) W(-)(1) in a 3.4 x 10(-)(4) mol dm(-)(3) DMF solution, respectively. Both 2 and 3 exhibit weaker NLO absorption and strong refractive properties, and their n(2) values are 4.53 x 10(-)(18) m(2) W(-)(1) for 2 in a 5.2 x 10(-)(4) mol dm(-)(3) DMF solution and 3.02 x 10(-)(18) m(2) W(-)(1) for 3 in a 4.35 x 10(-)(4) mol dm(-)(3) DMF solution. The chi((3)) values of 1, 2, and 3 were calculated to be 1.67 x 10(-)(11), 1.62 x 10(-)(11), and 1.08 x 10(-)(11) esu, respectively, and the values are larger than those of the reported coordination polymers. We deduce that the valence shell structures of metal ions may have some influence on the strength of NLO properties, and discuss the relationships between the crystal structures of coordination polymers and the observed NLO properties.
Huang, Wenzhu; Zhen, Tengkun; Zhang, Wentao; Zhang, Fusheng; Li, Fang
2015-01-01
Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs). However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain demodulation algorithm for FBG-based Fabry-Perot interferometers (FBG-FPs). The Hilbert transform is proposed for changing the Gaussian distribution of the two FBG-FPs’ reflection spectra, and a cross third-order cumulant is used to use the results of the Hilbert transform and get a group of noise-vanished signals which can be used to accurately calculate the wavelength difference of the two FBG-FPs. The benefit by these processes is that Gaussian noise in the spectra can be suppressed completely in theory and a higher resolution can be reached. In order to verify the precision and flexibility of this algorithm, a detailed theory model and a simulation analysis are given, and an experiment is implemented. As a result, a static-strain resolution of 0.9 nε under laboratory environment condition is achieved, showing a higher resolution than the traditional cross-correlation method. PMID:25923938
Yoneda, Kyohei; Nakano, Masayoshi; Fukuda, Kotaro; Matsui, Hiroshi; Takamuku, Shota; Hirosaki, Yuta; Kubo, Takashi; Kamada, Kenji; Champagne, Benoît
2014-08-25
The impact of intermolecular interactions on the third-order nonlinear optical (NLO) properties of open-shell molecular aggregates has been elucidated by considering one-dimensional aggregates of π-π stacked phenalenyl radicals with different intermolecular distances and the long-range corrected spin-unrestricted density functional theory method. In the phenalenyl dimer, which can be considered as a diradicaloid system, the diradical character strongly depends on the intermolecular distance, and the larger the intermolecular distance is, the larger the diradical character becomes. Then, around the equilibrium stacking distance that corresponds to an intermediate diradical character, its second hyperpolarizability (γ) is maximized and its value per monomer exhibits about a 30-fold enhancement with respect to the isolated phenalenyl monomer. This suggests that equilibrium is an optimal compromise between localization and delocalization of the radical electron pairs in such pancake bonding. No such effect was observed for the closed-shell coronene dimer. Moreover, when going from the dimer (diradical) to the tetramer (tetraradical), the γ-enhancement ratio increases nonlinearly with the aggregate size, whereas switching from the singlet to the highest spin (quintet) state causes a significant reduction of γ. Finally, for the tetramer, another one-order enhancement of γ is achieved for the dicationic singlet relative to its singlet neutral state. These results demonstrate the key role of intermolecular π-π stacking interactions and charge in open-shell (supra)molecular systems to achieve enhanced third-order NLO properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
NASA Astrophysics Data System (ADS)
Pérez-Moreno, Javier; Clays, Koen; Kuzyk, Mark G.
2010-05-01
We present a procedure for the modeling of the dispersion of the nonlinear optical response of complex molecular structures that is based strictly on the results from experimental characterization. We show how under some general conditions, the use of the Thomas-Kuhn sum-rules leads to a successful modeling of the nonlinear response of complex molecular structures.
NASA Astrophysics Data System (ADS)
Diercksen, G. H. F.; Sadlej, A. J.
1981-08-01
The many-body perturbation theory is applied for the calculation of the second- and third-order correlation corrections to the SCF HF dipole moments and polarizabilities of FH, H2O, NH3, and CH4. All calculations are performed by using the finite-field perturbation approach. The pertinent correlation corrections follow from the numerical differentiation of the second- and third-order field-dependent correlation energies. This computational scheme corresponds to a completely self-consistent treatment of the perturbation effects. The third-order corrected dipole moments are in excellent agreement with the experimental data and the best results of other authors. A comparison of the present perturbation corrections for polarizabilities with the PNO-CI and CEPA results of Werner and Meyer reveals that some cancellation of the third- and fourth-order correlation contributions can be expected. The second-order corrected polarizabilities are as a rule better than the results of the third-order perturbation approach. It is concluded that also for polarizabilities the low-order many-body perturbation scheme is able to account for the major portion of the relevant correlation effects.
Third order mode optically pumped semiconductor laser
NASA Astrophysics Data System (ADS)
De Rossi, A.; Semaltianos, N.; Chirlias, E.; Vinter, B.; Ortiz, V.; Berger, V.
2002-06-01
Lasing action on a third order waveguide mode is demonstrated at room temperature under optical pumping, in a specifically designed quantum well laser structure. The AlGaAs heterostructure involves barriers which ensure that the third order waveguide mode has a higher overlap with the single quantum well emitter than the fundamental mode. Third order mode operation of a laser structure opens the way to modal phase matched parametric down conversion inside the semiconductor laser itself. It is a first step towards the realization of semiconductor twin photon laser sources, needed for quantum information experiments.
On third order integrable vector Hamiltonian equations
NASA Astrophysics Data System (ADS)
Meshkov, A. G.; Sokolov, V. V.
2017-03-01
A complete list of third order vector Hamiltonian equations with the Hamiltonian operator Dx having an infinite series of higher conservation laws is presented. A new vector integrable equation on the sphere is found.
Filter for third order phase locked loops
NASA Technical Reports Server (NTRS)
Crow, R. B.; Tausworthe, R. C. (Inventor)
1973-01-01
Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.
Novel third-order Lovelock wormhole solutions
NASA Astrophysics Data System (ADS)
Mehdizadeh, Mohammad Reza; Lobo, Francisco S. N.
2016-06-01
In this work, we consider wormhole geometries in third-order Lovelock gravity and investigate the possibility that these solutions satisfy the energy conditions. In this framework, by applying a specific equation of state, we obtain exact wormhole solutions, and by imposing suitable values for the parameters of the theory, we find that these geometries satisfy the weak energy condition in the vicinity of the throat, due to the presence of higher-order curvature terms. Finally, we trace out a numerical analysis, by assuming a specific redshift function, and find asymptotically flat solutions that satisfy the weak energy condition throughout the spacetime.
Linearizability for third order evolution equations
NASA Astrophysics Data System (ADS)
Basarab-Horwath, P.; Güngör, F.
2017-08-01
The problem of linearization for third order evolution equations is considered. Criteria for testing equations for linearity are presented. A class of linearizable equations depending on arbitrary functions is obtained by requiring presence of an infinite-dimensional symmetry group. Linearizing transformations for this class are found using symmetry structure and local conservation laws. A number of special cases as examples are discussed. Their transformation to equations within the same class by differential substitutions and connection with KdV and mKdV equations is also reviewed in this framework.
A pseudo third order symplectic integrator
NASA Astrophysics Data System (ADS)
Liu, Fu-Yao; Wu, Xin; Lu, Ben-Kui
2005-01-01
The symplectic integrator has been regarded as one of the optimal tools for research on qualitative secular evolution of Hamiltonian systems in solar system dynamics. An integrable and separate Hamiltonian system H = H0 + Σi=1NɛiHi (ɛi ≪ 1) forms a pseudo third order symplectic integrator, whose accuracy is approximately equal to that of the first order corrector of the Wisdom-Holman second order symplectic integrator or that of the Forest-Ruth fourth order symplectic integrator. In addition, the symplectic algorithm with force gradients is also suited to the treatment of the Hamiltonian system H = H0(q,p) + ɛH1(q), with accuracy better than that of the original symplectic integrator but not superior to that of the corresponding pseudo higher order symplectic integrator.
Green, Anthony J; Space, Brian
2015-07-23
Sum frequency vibrational spectroscopy (SFVS), a second-order optical process, is interface-specific in the dipole approximation [Perry, A.; Neipert, C.; Moore, P.; Space, B. Chem. Rev. 2006, 106, 1234-1258; Richmond, G. L. Chem. Rev. 2002, 102, 2693-2724; Byrnes, S. J.; Geissler, P. L.; Shen, Y. R. Chem. Phys. Lett. 2011, 516, 115-124]. At charged interfaces, the experimentally detected signal is a combination of enhanced second-order and static-field-induced third-order contributions due to the existence of a static field. Evidence of the importance/relative magnitude of this third-order contribution is seen in the literature [Ong, S.; Zhao, X.; Eisenthal, K. B. Chem. Phys. Lett. 1992, 191, 327-335; Zhao, X.; Ong, S.; Eisenthal, K. B. Chem. Phys. Lett. 1993, 202, 513-520; Shen, Y. R. Appl. Phys. B: Laser Opt. 1999, 68, 295-300], but a molecularly detailed approach to separately calculating the second- and third-order contributions is difficult to construct. Recent work presented a novel molecular dynamics (MD)-based theory that provides a direct means to calculate the third-order contributions to SFVS spectra at charged interfaces [Neipert, C.; Space, B. J. Chem. Phys. 2006, 125, 224706], and a hyperpolarizability model for water was developed as a prerequisite to practical implementation [Neipert, C.; Space, B. Comput. Lett. 2007, 3, 431-440]. Here, these methods are applied to a highly abstracted/idealized silica/water interface, and the results are compared to experimental data for water at a fused quartz surface. The results suggest that such spectra have some quite general spectral features.
NASA Technical Reports Server (NTRS)
Langhoff, S. R.; Scott, W. R.; Suzuki, N.; Chong, D. P.
1979-01-01
Ordinary Rayleigh-Schroudinger perturbation theory with Moller-Plesset (RSMP) partitioning is used to calculate second- and third-order correlation corrections to the CHF polarizability and dipole moment of the water molecule by a finite-field procedure. Pade approximants are found to be useful in accelerating the convergence of the property perturbation expansions. Field-induced polarization functions suitable for polarizability calculations are determined. The average polarizability calculated, neglecting vibrational averaging, with Dunning's (9s5p/4s-4s2p/2s) contracted GTO basis set augmented by field-induced lslp2d/lp polarization functions is within 3 per cent of the experimental result. Correlation corrections to the dipole moment and polarizability of the water molecule calculated by the finite-field RSMP and single + double excitation CI(SDCI) methods for the same basis set are found to be in close agreement. The RSMP approach has the advantages of being size-consistent and of being capable of greater efficiency than the SCDI method. Comparative calculations carried out using Epstein-Nesbet partitioning show that through third order RSEN correlation perturbation expansions for the dipole moment and polarizability are less rapidly convergent than RSMP expansions. However, reasonable accord with RSMP results can be achieved by using Pade approximants to accelerate the convergence of RSEN energy perturbation expansions. The convergence of RSMP property correlation expansions based on the zeroth-order uncoupled-Hartree-Fock (UCHF) and coupled-Hartree-Fock (CHF) approximations are compared through third order. Whereas the CHF + RSMP expansions are for practical purposes fully converged, the UCHF + RSMP expansions are not adequately converged.
Is there a third order phase transition for supercritical fluids?
Zhu, Jinglong; Zhang, Pingwen; Wang, Han; Site, Luigi Delle
2014-01-07
We prove that according to Molecular Dynamics (MD) simulations of liquid mixtures of Lennard-Jones (L-J) particles, there is no third order phase transition in the supercritical regime beyond Andrew's critical point. This result is in open contrast with recent theoretical studies and experiments which instead suggest not only its existence but also its universality regarding the chemical nature of the fluid. We argue that our results are solid enough to go beyond the limitations of MD and the generic character of L-J models, thus suggesting a rather smooth liquid-vapor thermodynamic behavior of fluids in supercritical regime.
Is there a third order phase transition for supercritical fluids?
Zhu, Jinglong; Zhang, Pingwen; Wang, Han Site, Luigi Delle
2014-01-07
We prove that according to Molecular Dynamics (MD) simulations of liquid mixtures of Lennard-Jones (L-J) particles, there is no third order phase transition in the supercritical regime beyond Andrew's critical point. This result is in open contrast with recent theoretical studies and experiments which instead suggest not only its existence but also its universality regarding the chemical nature of the fluid. We argue that our results are solid enough to go beyond the limitations of MD and the generic character of L-J models, thus suggesting a rather smooth liquid-vapor thermodynamic behavior of fluids in supercritical regime.
NASA Astrophysics Data System (ADS)
Maidur, Shivaraj R.; Patil, Parutagouda Shankaragouda; Ekbote, Anusha; Chia, Tze Shyang; Quah, Ching Kheng
2017-09-01
In the present work, the title chalcone, (2E)-3-(4-fluorophenyl)-1-(4-{[(1E)-(4-fluorophenyl) methylene]amino}phenyl)prop-2-en-1-one (abbreviated as FAMFC), was synthesized and structurally characterized by single-crystal X-ray diffraction. The compound is crystallized in the monoclinic system with non-centrosymmetric space group P21 and hence it satisfies the essential condition for materials to exhibit second-order nonlinear optical properties. The molecular structure was further confirmed by using FT-IR and 1H NMR spectroscopic techniques. The title crystal is transparent in the Vis-NIR region and has a direct band gap. The third-order nonlinear optical properties were investigated in solution (0.01 M) by Z-scan technique using a continuous wave (CW) DPSS laser at the wavelength of 532 nm. The title chalcone exhibited significant two-photon absorption (β = 35.8 × 10- 5 cm W- 1), negative nonlinear refraction (n2 = - 0.18 × 10- 8 cm2 W- 1) and optical limiting (OL threshold = 2.73 kJ cm- 2) under the CW regime. In support of the experimental results, a comprehensive theoretical study was carried out on the molecule of FAMFC using density functional theory (DFT). The optimized geometries and frontier molecular orbitals were calculated by employing B3LYP/6-31 + G level of theory. The optimized molecular structure was confirmed computationally by IR vibrational and 1H NMR spectral analysis. The experimental UV-Vis-NIR spectrum was interpreted using computational chemistry under time-dependent DFT. The static and dynamic NLO properties such as dipole moments (μ), polarizability (α), and first hyperpolarizabilities (β) were computed by using finite field method. The obtained dynamic first hyperpolarizability β(- 2ω;ω,ω) at input frequency ω = 0.04282 a.u. is predicted to be 161 times higher than urea standard. The electronic excitation energies and HOMO-LUMO band gap for FAMFC were also evaluated by DFT. The experimental and theoretical results are in good
Maidur, Shivaraj R; Patil, Parutagouda Shankaragouda; Ekbote, Anusha; Chia, Tze Shyang; Quah, Ching Kheng
2017-09-05
In the present work, the title chalcone, (2E)-3-(4-fluorophenyl)-1-(4-{[(1E)-(4-fluorophenyl) methylene]amino}phenyl)prop-2-en-1-one (abbreviated as FAMFC), was synthesized and structurally characterized by single-crystal X-ray diffraction. The compound is crystallized in the monoclinic system with non-centrosymmetric space group P21 and hence it satisfies the essential condition for materials to exhibit second-order nonlinear optical properties. The molecular structure was further confirmed by using FT-IR and (1)H NMR spectroscopic techniques. The title crystal is transparent in the Vis-NIR region and has a direct band gap. The third-order nonlinear optical properties were investigated in solution (0.01M) by Z-scan technique using a continuous wave (CW) DPSS laser at the wavelength of 532nm. The title chalcone exhibited significant two-photon absorption (β=35.8×10(-5)cmW(-1)), negative nonlinear refraction (n2=-0.18×10(-8)cm(2)W(-1)) and optical limiting (OL threshold=2.73kJcm(-2)) under the CW regime. In support of the experimental results, a comprehensive theoretical study was carried out on the molecule of FAMFC using density functional theory (DFT). The optimized geometries and frontier molecular orbitals were calculated by employing B3LYP/6-31+G level of theory. The optimized molecular structure was confirmed computationally by IR vibrational and (1)H NMR spectral analysis. The experimental UV-Vis-NIR spectrum was interpreted using computational chemistry under time-dependent DFT. The static and dynamic NLO properties such as dipole moments (μ), polarizability (α), and first hyperpolarizabilities (β) were computed by using finite field method. The obtained dynamic first hyperpolarizability β(-2ω;ω,ω) at input frequency ω=0.04282a.u. is predicted to be 161 times higher than urea standard. The electronic excitation energies and HOMO-LUMO band gap for FAMFC were also evaluated by DFT. The experimental and theoretical results are in good agreement, and
Brown, Karl
1998-10-28
TRANSPORT has been in existence in various evolutionary versions since 1963. The present version of TRANSPORT is a first-, second-, and third-order matrix multiplication computer program intended for the design of static-magnetic beam transport systems.
NASA Astrophysics Data System (ADS)
Renaud, Guillaume; Talmant, Maryline; Marrelec, Guillaume
2016-10-01
The nonlinear elasticity of solids at the microstrain level has been recently studied by applying dynamic acousto-elastic testing. It is the analog of conventional quasi-static acousto-elastic experiments but the strain-dependence (or stress-dependence) of ultrasonic wave-speed is measured with an applied strain ranging from 10-7 to 10-5 and produced by a stationary elastic wave. In conventional quasi-static acousto-elastic experiments, the strain is applied in a quasi-static manner; it exceeds 10-4 and can reach 10-2. In this work, we apply dynamic acousto-elastic testing to measure the third-order elastic constants of two isotropic materials: polymethyl methacrylate and dry Berea sandstone. The peak amplitude of the dynamic applied strain is 8 × 10-6. The method is shown to be particularly suitable for materials exhibiting large elastic nonlinearity like sandstones, since the measurement is performed in the domain of validity of the third-order hyperelastic model. In contrast, conventional quasi-static acousto-elastic experiments in such materials are often performed outside the domain of validity of the third-order hyperelastic model and the stress-dependence of the ultrasonic wave-speed must be extrapolated at zero stress, leading to approximate values of the third-order elastic constants. The uncertainty of the evaluation of the third-order elastic constants is assessed by repeating multiple times the measurements and with Monte-Carlo simulations. The obtained values of the Murnaghan third-order elastic constants are l = -73 GPa ± 9%, m = -34 GPa ± 9%, and n = -61 GPa ± 10% for polymethyl methacrylate, and l = -17 000 GPa ± 20%, m = -11 000 GPa ± 10%, and n = -30 000 GPa ± 20% for dry Berea sandstone.
Photoassociation dynamics driven by second- and third-order phase-modulated laser fields
NASA Astrophysics Data System (ADS)
Wang, Meng; Chen, Mao-Du; Hu, Xue-Jin; Li, Jing-Lun; Cong, Shu-Lin
2016-05-01
We investigate theoretically the photoassociation dynamics of ultracold 85Rb atoms driven by second- and third-order phase-modulated laser fields. The interplay between the second-order and third-order terms of the phase-modulated pulse has an obvious influence on photoassociation dynamics. The different combinations of the second-order and third-order phase coefficients lead to different pulse shapes. Most of the molecular population in the excited electronic state driven only by the third-order phase pulses can be distributed in a single vibrational level. The second-order term of the phase-modulated pulse can change the instantaneous frequency, and therefore the final population is distributed on several resonant vibrational levels, instead of concentrating on a single level. Although the second- and third-order phase-modulated pulse covers more resonant vibrational levels, the total population on the resonant vibrational levels is much smaller than that controlled only by the third-order phase pulse. In particular, the third-order term of the phase-modulated pulse can weaken the ‘multiple interaction’ to some degree.
Yesudas, Kada
2013-11-28
A systematic study is carried out to find the exact crossover point from symmetric to asymmetric configurations (symmetry-breaking) in a series of cationic cyanine dyes. Hybrid density functional with varying exact-exchange admixture has been used to understand the impact of HF exchange both in the gas phase and in the presence of dielectric medium. This approach provides a basis for understanding the electronic structure and photophysical properties of cyanine dyes. The crossover points predicted using this method are in good agreement with the experiment. The SAC-CI method is used to evaluate the lowest S0 → S1 transition energies in the gas phase. These transitions are preferably dominated by the promotion of an electron from HOMO → LUMO. The average static third-order polarizabilities, [γ], are obtained within the three-state model approximation. The analysis showed that for symmetric cyanines, the calculated [γ] values are large and negative, mainly originated from the large S0 → S1 transition moments and small S0 → S1 transition energies. For asymmetric cyanines, the [γ] values are positive and mainly originate from the large change in the ground and first excited state dipole moments. However, both configurations do not include contributions from the two-photon absorption. Further, the localization of charge densities in the HOMO and LUMO indicates that the symmetric and asymmetric cyanines act as promising materials for molecular wires and molecular switches which are fundamental building blocks for molecular electronic devices.
NASA Astrophysics Data System (ADS)
Altürk, Sümeyye; Avci, Davut; Tamer, Ömer; Atalay, Yusuf
2016-03-01
It is well known that the practical applications of second-order and third-order nonlinear optical (NLO) materials have been reported in modern technology, such as optical data processing, transmission and storage, etc. In this respect, the linear and nonlinear optical parameters (the molecular static polarizability (α), and the first-order static hyperpolarizability (β0), the second-order static hyperpolarizability (γ)), UV-vis spectra and HOMO and LUMO energies of 2-(1'-(4'''-Methoxyphenyl)-5'-(thien-2″-yl)pyrrol-2'-yl)-1,3-benzothiazole were investigated by using the HSEh1PBE/6-311G(d,p) level of density functional theory. The UV-vis spectra were simulated using TD/HSEh1PBE/6- 311G(d,p) level, and the major contributions to the electronic transitions were obtained. The molecular hardness (η) and electronegativity (χ) parameters were also obtained by using molecular frontier orbital energies. The NLO parameters of the title compound were calculated, and obtained data were compared with that of para-Nitroaniline (pNA) which is a typical NLO material and the corresponding experimental data. Obtained data of the chromosphere display significant molecular second-and third-nonlinearity.
Third-order chromatic dispersion stabilizes Kerr frequency combs.
Parra-Rivas, Pedro; Gomila, Damià; Leo, François; Coen, Stéphane; Gelens, Lendert
2014-05-15
Using numerical simulations of an extended Lugiato-Lefever equation we analyze the stability and nonlinear dynamics of Kerr frequency combs generated in microresonators and fiber resonators, taking into account third-order dispersion effects. We show that cavity solitons underlying Kerr frequency combs, normally sensitive to oscillatory and chaotic instabilities, are stabilized in a wide range of parameter space by third-order dispersion. Moreover, we demonstrate how the snaking structure organizing compound states of multiple cavity solitons is qualitatively changed by third-order dispersion, promoting an increased stability of Kerr combs underlined by a single cavity soliton.
Third order TRANSPORT with MAD (Methodical Accelerator Design) input
Carey, D.C.
1988-09-20
This paper describes computer-aided design codes for particle accelerators. Among the topics discussed are: input beam description; parameters and algebraic expressions; the physical elements; beam lines; operations; and third-order transfer matrix. (LSP)
A third order Runge-Kutta algorithm on a manifold
NASA Technical Reports Server (NTRS)
Crouch, P. E.; Grossman, R. G.; Yan, Y.
1992-01-01
A third order Runge-Kutta type algorithm is described with the property that it preserves certain geometric structures. In particular, if the algorithm is initialized on a Lie group, then the resulting iterates remain on the Lie group.
Third order transport coefficients for electrons and positrons in gases
NASA Astrophysics Data System (ADS)
Dujko, Sasa; Simonovic, Ilija; White, Ronald; Petrovic, Zoran
2016-09-01
Third order transport coefficients (the skewness tensor) of the electron and positron swarms, in atomic and molecular gases, are investigated. The knowledge of the skewness tensor is necessary for the conversion of the hydrodynamic transport coefficients to the arrival time and steady-state Townsend transport data as well as for the determination of the deviations of the spatial density profiles from an ideal Gaussian. In this work, we investigate the structure and symmetries along individual elements of the skewness tensor by the group projector method. Individual components of the skewness tensor are calculated using a Monte Carlo simulation technique and multi term theory for solving the Boltzmann equation. Results obtained by these two methods are in excellent agreement. We extend previous studies by considering the sensitivity of the skewness components to explicit and implicit effects of non-conservative collisions, post-ionization energy partitioning, and inelastic collisions. The errors of the two term approximation for solving the Boltzmann equation are highlighted. We also investigate the influence of a magnetic field on the skewness tensor in varying configurations of electric and magnetic fields. Among many interesting points, we have observed a strong correlation between the skewness and diffusion.
Dynamics of platicons due to third-order dispersion
NASA Astrophysics Data System (ADS)
Lobanov, Valery E.; Cherenkov, Artem V.; Shitikov, Artem E.; Bilenko, Igor A.; Gorodetsky, Michael L.
2017-07-01
Dynamics of platicons caused by the third-order dispersion is studied. It is shown that under the influence of the third-order dispersion platicons obtain angular velocity depending both on dispersion and on detuning value. A method of tuning of platicon associated optical frequency comb repetition rate is proposed. Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.
Holographic charged fluid dual to third order Lovelock gravity
NASA Astrophysics Data System (ADS)
Zou, De-Cheng; Zhang, Shao-Jun; Wang, Bin
2013-04-01
We study the dual fluid on a finite cutoff surface outside the black brane horizon in the third order Lovelock gravity. Using nonrelativistic long-wavelength expansion, we obtain the incompressible Navier-Stokes equations of dual fluid with external force density on the finite cutoff surface. The viscosity to entropy density ratio η/s is independent of the cutoff surface and does not get modification from the third order Lovelock gravity influence. The obtained ratio agrees with the results obtained by using other methods, such as the Kubo formula at the AdS boundary and the membrane paradigm at the horizon in the third order Lovelock gravity. These results can be related by Wilson renormalization group flow. However the kinematic viscosity receives correction from the third order Lovelock term. We show that the equivalence between the isentropic flow of the fluid and the radial component of the gravitational equation observed in the Einstein and Gauss-Bonnet gravities also holds in the third order Lovelock gravity. This generalization brings more understanding of relating the gravity theory to the dual fluid.
Higher-dimensional thin-shell wormholes in third-order Lovelock gravity
NASA Astrophysics Data System (ADS)
Mehdizadeh, Mohammad Reza; Zangeneh, Mahdi Kord; Lobo, Francisco S. N.
2015-08-01
In this paper, we explore asymptotically flat charged thin-shell wormholes of third order Lovelock gravity in higher dimensions, taking into account the cut-and-paste technique. Using the generalized junction conditions, we determine the energy-momentum tensor of these solutions on the shell, and explore the issue of the energy conditions and the amount of normal matter that supports these thin-shell wormholes. Our analysis shows that for negative second-order and positive third-order Lovelock coefficients, there are thin-shell wormhole solutions that respect the weak energy condition. In this case, the amount of normal matter increases as the third-order Lovelock coefficient decreases. We also find novel solutions which possess specific regions where the energy conditions are satisfied for the case of a positive second-order and negative third-order Lovelock coefficients. Finally, a linear stability analysis in higher dimensions around the static solutions is carried out. Considering a specific cold equation of state, we find a wide range of stability regions.
Achromatic phase matching at third orders of dispersion
Richman, Bruce
2003-10-21
Achromatic phase-matching (APM) is used for efficiently multiplying the frequency of broad bandwidth light by using a nonlinear optical medium comprising a second-harmonic generation (SHG) crystal and stationary optical elements whose configuration, properties, and arrangement have been optimized to match the angular dispersion characteristics of the SHG crystal to at least the third order. These elements include prisms and diffraction gratings for directing an input light beam onto the SHG crystal such that each ray wavelength is aligned to match the phase-matching angle for the crystal at each wavelength of light to at least the third order and such that every ray wavelength overlap within the crystal.
Superintegrability with second- and third-order integrals of motion
Winternitz, P.
2009-05-15
Superintegrable systems in two-dimensional Euclidean space E{sub 2} with scalar potentials and integrals of motion that are second- or third-order polynomials in the momenta are discussed. We review old results, obtained in collaboration with Ya.A. Smorodinsky more than 40 years ago and present new ones that are their continuation.
Third-order phase-locked loop receiver
NASA Technical Reports Server (NTRS)
Crow, R. B.; Tausworthe, R. C.
1974-01-01
Third-order extension to present second-order systems extends their Doppler tracking capabilities. It widens receiver pull-in range, decreases pull-in time, lowers voltage-controlled oscillator (VCO) noise (determining when no signal is present), and lessens susceptibility to VCO drift.
The third-order nonlinear optical properties in polymer ferroelectrics
NASA Astrophysics Data System (ADS)
Verkhovskaya, K. A.; Grishina, A. D.; Krivenko, T. V.; Savel'ev, V. V.; Laryushkin, A. S.; Vannikov, A. V.
2017-04-01
The third-order susceptibility of vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymer are analyzed by using the z-scan technique with a nanosecond laser as an excitation source. It is established that optical transmittance of the VDF-TrFE samples decreases after their polarization in an electric field.
Third-Order Family of Methods in Banach Spaces
2011-01-24
8. [13] J.-S. Kou , Y .-T. Li, Modified Chebyshev’s method free from second derivative for non-linear equations, Appl. Math. Comp. 187 (2007), 1027–1032...14] J.-S. Kou , Y .-T. Li, X.-H. Wang, A modification of Newton method with third-order conver- gence, Appl. Math. Comput. 181 (2006), 1106–1111. [15
NASA Astrophysics Data System (ADS)
Senthil, K.; Kalainathan, S.; Kondo, Y.; Hamada, F.; Yamada, M.
2017-05-01
Organic 2-[2-(4-Ethoxy-phenyl)-vinyl]-1-ethyl-stilbazolium iodide (EESI), a derivative of the stilbazolium family single crystal was synthesized by condensation method. Nearly perfect as-gown single crystals of EESI structure was confirmed by single-crystal X-ray diffraction studies. The crystal has a triclinic system with the space group P-1, the molecule consists of one pyridinium cation, one iodide anion, and 0·5H2O molecules. The nature of charge transfer, molecular properties, electrostatic potential map, and HOMO-LUMO energy gap of EESI have been theoretically investigated by Sparton'10 V1.0.1 program. The optical transparency of EESI was studied by Uv-Visible spectral analysis. The growth features were observed during the etching studies using a Carl Zeiss optical microscope (50X magnification). The mechanical behavior of the crystal was estimated by Vickers microhardness test, which shows reverse indentation size effect (RISE) with good mechanical stability. Both the dielectric constant and dielectric loss increases with the increasing temperature and attain almost constant at higher frequencies, which justify the crystal quality and essential parameter for electro-optic device applications. The complex impedance analysis explains the electrical property of EESI. TGA and DTA measurements determined the thermal stability of the grown crystal. Laser-induced damage threshold energy measurements exhibit that the excellent resistance with good threshold energy up to 2.08 GW/cm2 that was found to be more than that of some known organic and inorganic NLO crystals. Photoconductivity of EESI crystal confirms that the positive photoconductivity nature. Also, the third-order nonlinear optical (NLO) properties of EESI were investigated by using the single beam Z-scan technique under the Visible light (632.8 nm) region. The results show that EESI has effective third-order nonlinear optical property with the nonlinear refractive index n2 =1.787×10-11m2/W, third-order
Mark, J. Abraham Hudson Peter, A. John
2014-04-24
Third order susceptibility of third order harmonic generation is investigated in a Zn{sub 0.1}Mg{sub 0.9}Se/Zn{sub 0.8}Mg{sub 0.2}Se/Zn{sub 0.1}Mg{sub 0.9}Se quantum well in the presence of magnetic field strength. The confinement potential is considered as the addition of energy offsets of the conduction band (or valence band) and the strain-induced potential in our calculations. The material dependent effective mass is followed throughout the computation because it has a high influence on the electron energy levels in low dimensional semiconductor systems.
NASA Astrophysics Data System (ADS)
Mark, J. Abraham Hudson; Peter, A. John
2014-04-01
Third order susceptibility of third order harmonic generation is investigated in a Zn0.1Mg0.9Se/Zn0.8Mg0.2Se/Zn0.1Mg0.9Se quantum well in the presence of magnetic field strength. The confinement potential is considered as the addition of energy offsets of the conduction band (or valence band) and the strain-induced potential in our calculations. The material dependent effective mass is followed throughout the computation because it has a high influence on the electron energy levels in low dimensional semiconductor systems.
Thermodynamics of asymptotically flat charged black holes in third order Lovelock gravity
Dehghani, M.H.; Shamirzaie, M.
2005-12-15
We present a new class of asymptotically flat charge static solutions in third order Lovelock gravity. These solutions present black hole solutions with two inner and outer event horizons, extreme black holes, or naked singularities provided the parameters of the solutions are chosen suitable. We find that the uncharged asymptotically flat solutions can present black holes with two inner and outer horizons. This kind of solution does not exist in Einstein or Gauss-Bonnet gravity, and it is a special effect in third order Lovelock gravity. We compute temperature, entropy, charge, electric potential, and mass of the black hole solutions, and find that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis by computing the determinant of the Hessian matrix of the mass with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles, and show that there exists only an intermediate stable phase.
NASA Astrophysics Data System (ADS)
Karakaş, Aslı; Ünver, Hüseyin; Elmali, Ayhan
2008-04-01
N-(3-Hydroxybenzalidene)4-bromoaniline has been synthesized. Its crystal structure has been determined by X-ray diffraction analysis. To investigate microscopic third-order nonlinear optical (NLO) behavior of the title compound, we have computed both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities ( α) and second hyperpolarizabilities ( γ) at λ = 825-1125 nm and 1050-1600 nm wavelength areas using time-dependent Hartree-Fock (TDHF) method. The one-photon absorption (OPA) characterization has been theoretically obtained by means of configuration interaction (CI) method. The maximum OPA wavelengths are estimated in the UV region to be shorter than 450 nm, showing good optical transparency to the visible light. According to ab-initio calculation results on (hyper)polarizabilities, the synthesized molecule exhibits second hyperpolarizabilities with non-zero values, and it might have microscopic third-order NLO behavior.
Constructing higher-order hydrodynamics: The third order
NASA Astrophysics Data System (ADS)
Grozdanov, Sašo; Kaplis, Nikolaos
2016-03-01
Hydrodynamics can be formulated as the gradient expansion of conserved currents in terms of the fundamental fields describing the near-equilibrium fluid flow. In the relativistic case, the Navier-Stokes equations follow from the conservation of the stress-energy tensor to first order in derivatives. In this paper, we go beyond the presently understood second-order hydrodynamics and discuss the systematization of obtaining the hydrodynamic expansion to an arbitrarily high order. As an example of the algorithm that we present, we fully classify the gradient expansion at third order for neutral fluids in four dimensions, thus finding the most general next-to-leading-order corrections to the relativistic Navier-Stokes equations in curved space-time. In doing so, we list 20 new transport coefficient candidates in the conformal case and 68 in the nonconformal case. As we do not consider any constraints that could potentially arise from the local entropy current analysis, this is the maximal possible set of neutral third-order transport coefficients. To investigate the physical implications of these new transport coefficients, we obtain the third-order corrections to the linear dispersion relations that describe the propagation of diffusion and sound waves in relativistic fluids. We also compute the corrections to the scalar (spin-2) two-point correlation function of the third-order stress-energy tensor. Furthermore, as an example of a nonlinear hydrodynamic flow, we calculate the third-order corrections to the energy density of a boost-invariant Bjorken flow. Finally, we apply our field theoretic results to the N =4 supersymmetric Yang-Mills fluid at infinite 't Hooft coupling and an infinite number of colors to find the values of five new linear combinations of the conformal transport coefficients.
Resonance scattering at third-order exceptional points
NASA Astrophysics Data System (ADS)
Heiss, W. D.; Wunner, G.
2015-08-01
We analyze scattering cross sections at and near third-order exceptional points (EP3), i.e., points in physical parameter space where three energies and eigenfunctions coincide. At an EP3, the Green’s function contains a pole of third order, in addition to poles of second and first order. We show that the interference of the three pole terms produces a rich variety of line shapes at the exceptional point and in its neighbourhood. This is demonstrated by extending previous work on two harmonic oscillators to a system of three driven coupled damped oscillators. We also discuss the similarities and the differences in the behaviour of the amplitudes in the classical problem and the scattering cross sections in the quantum mechanical problem at the EP3.
Growth and characterization of third order nonlinear optical material: Isatin
NASA Astrophysics Data System (ADS)
Thirumalaiselvam, B.; Kanagadurai, R.; Jayaraman, D.; Natarajan, V.
2013-10-01
Isatin, an indole derivative, is a bioactive and nonlinear active material with broad range of applications in synthetic, biological and clinical activity and optoelectronics and photonics. Isatin single crystals were grown by the solution growth method. The grown crystals were characterized by single crystal XRD, UV-vis-NIR, FTIR spectral analysis, dielectric and thermal studies. Kurtz and Perry powder technique reveals the absence of second harmonic generation. The estimations of third order non-linear optical properties like non-linear absorption co-efficient (β), non-linear refractive index (n2) and susceptibility [χ(3)] using Z-scan technique confirm the third order NLO behaviour of the material and these results indicate that the crystal exhibits saturation absorption and self-focusing performance.
Third-order solution of an artificial-satellite theory
NASA Technical Reports Server (NTRS)
Kinoshita, H.
1977-01-01
A third-order solution was developed for the motions of artificial satellites moving in the gravitational field of the earth, whose potential includes the second-, third-, and fourth-order zonal harmonics. Third-order periodic perturbations with fourth-order secular perturbations were derived by the Hori perturbation method. All quantities were expanded into power series of the eccentricity, but the solution was obtained so as to be closed with respect to the inclination. A comparison with the results of numerical integration of the equations of motion indicates that the solution can predict the position of a close-earth, small-eccentricity satellite with an accuracy of better than one cm over a period of one month.
Efficiency-enhanced third-order grating coupler.
Ura, S; Fujii, T; Suhara, T; Nishihara, H
1999-05-10
A third-order grating coupler with a grating period 3 times that of a first-order grating is discussed in terms of efficiency enhancement. A reflection film is integrated between the optical buffer layer and the substrate beneath the grating-guiding core. The power-distribution ratio for each diffracted wave depends on the optical buffer layer's thickness because of interference effects. The thickness is determined to suppress first- and second-order diffraction and to enhance the power distribution to the output air-radiation wave generated by third-order diffraction. A demonstrator was designed and examined at a wavelength of 0.82 microm. The measured output coupling efficiency was 40%, whereas the theoretical prediction was 60%.
Third order equations of motion and the Ostrogradsky instability
NASA Astrophysics Data System (ADS)
Motohashi, Hayato; Suyama, Teruaki
2015-04-01
It is known that any nondegenerate Lagrangian containing time derivative terms higher than first order suffers from the Ostrogradsky instability, pathological excitation of positive and negative energy degrees of freedom. We show that, within the framework of analytical mechanics of point particles, any Lagrangian for third order equations of motion, which evades the nondegeneracy condition, still leads to the Ostrogradsky instability. Extension to the case of higher odd order equations of motion is also considered.
Third-order TRANSPORT: A computer program for designing charged particle beam transport systems
Carey, D.C.; Brown, K.L.; Rothacker, F.
1995-05-01
TRANSPORT has been in existence in various evolutionary versions since 1963. The present version of TRANSPORT is a first-, second-, and third-order matrix multiplication computer program intended for the design of static-magnetic beam transport systems. This report discusses the following topics on TRANSPORT: Mathematical formulation of TRANSPORT; input format for TRANSPORT; summaries of TRANSPORT elements; preliminary specifications; description of the beam; physical elements; other transformations; assembling beam lines; operations; variation of parameters for fitting; and available constraints -- the FIT command.
D'silva, E.D.; Podagatlapalli, G. Krishna; Venugopal Rao, S.; Dharmaprakash, S.M.
2012-11-15
Graphical abstract: Photograph and schematic representation of Z-scan experimental setup used to investigate third order nonlinear properties of the chalcone materials. Highlights: ► Br and NO{sub 2} substituted chalcone derivatives were exposed to picosecond laser pulses. ► Third-order nonlinear optical (NLO) properties were investigated. ► Compounds show promising third-order and optical limiting properties. ► These materials found suitable for electrical and optical applications. -- Abstract: In this paper we present results from the experimental study of third-order nonlinear optical (NLO) properties of three molecules of Br and NO{sub 2} substituted chalcone derivatives namely (2E)-1-(4-bromophenyl)-3-[4(methylsulfanyl)phenyl]prop-2-en-1-one (4Br4MSP), (2E)-1-(3-bromophenyl)-3-[4-(methylsulfanyl) phenyl]prop-2-en-1-one (3Br4MSP) and (2E)-3[4(methylsulfanyl) phenyl]-1-(4-nitrophenyl)prop-2-en-1-one (4N4MSP). The NLO properties have been investigated by Z-scan technique using 2 ps laser pulses at 800 nm. The nonlinear refractive indices, nonlinear absorption coefficient, and the magnitude of third-order susceptibility have been determined. The values obtained are of the order of 10{sup −7} cm{sup 2}/GW, 10{sup −3} cm/GW and 10{sup −14} esu respectively. The molecular second hyperpolarizability for the chalcone derivatives is of the order of 10{sup −32} esu. The coupling factor, excited state cross section, ground state cross section etc. were determined. The optical limiting (OL) property was studied. The results suggest that the nonlinear properties investigated for present chalcones are comparable with some of the reported chalcone derivatives and can be desirable for NLO applications.
Multifield cosmological perturbations at third order and the ekpyrotic trispectrum
Lehners, Jean-Luc; Renaux-Petel, Sebastien
2009-09-15
Using the covariant formalism, we derive the equations of motion for adiabatic and entropy perturbations at third order in perturbation theory for cosmological models involving two scalar fields. We use these equations to calculate the trispectrum of ekpyrotic and cyclic models in which the density perturbations are generated via the entropic mechanism. In these models, the conversion of entropy into curvature perturbations occurs just before the big bang, either during the ekpyrotic phase or during the subsequent kinetic energy dominated phase. In both cases, we find that the nonlinearity parameters f{sub NL} and g{sub NL} combine to leave a very distinct observational imprint.
Third-order nonlinear polarizabilities of a homologous series of symmetric cyanines
NASA Astrophysics Data System (ADS)
Johr, T.; Werncke, W.; Pfeiffer, M.; Lau, A.; Dähne, L.
1995-12-01
Third-order nonlinear polarizabilities of the homologous series of bis(dimethylamino)methine dyes (mono-, tri-, penta-, hepta- and non-amethine) were derived in the static frequency limit from dispersion curves measured by four-wave mixing techniques. Positive signs of the hyperpolarizabilities are obtained for mono- and trimethine: They are caused by positive contributions from δ electrons dominating the negative π electron contributions in the short chains. In the longer chains the hyperpolarizabilities exhibit negative signs and a strong enhancement (≈ - N11) with increasing chain lengths due to the growing number ( N) of contributing π electrons. A static hyperpolarizability of ≈ -1 × 10 -33 esu which is obtained for the nonamethine, is the largest off-resonant experimental value reported for a polymethine dye.
Third order nonlinear optical properties of bismuth zinc borate glasses
Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.
2013-12-28
Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.
Asymptotically flat radiating solutions in third order Lovelock gravity
Dehghani, M. H.; Farhangkhah, N.
2008-09-15
In this paper, we present an exact spherically symmetric solution of third order Lovelock gravity in n dimensions which describes the gravitational collapse of a null dust fluid. This solution is asymptotically (anti-)de Sitter or flat depending on the choice of the cosmological constant. Using the asymptotically flat solution for n{>=}7 with a power-law form of the mass as a function of the null coordinate, we present a model for a gravitational collapse in which a null dust fluid radially injects into an initially flat and empty region. It is found that a naked singularity is inevitably formed whose strength is different for the n=7 and n{>=}8 cases. In the n=7 case, the limiting focusing condition for the strength of curvature singularity is satisfied. But for n{>=}8, the strength of curvature singularity depends on the rate of increase of mass of the spacetime. These considerations show that the third order Lovelock term weakens the strength of the curvature singularity.
Third-order intermodulation distortion in graphene resonant channel transistors
NASA Astrophysics Data System (ADS)
Lekas, Michael; Lee, Sunwoo; Cha, Wujoon; Hone, James; Shepard, Kenneth
2015-02-01
Third-order intermodulation distortion (IM3) is an important metric for electromechanical resonators used in radio frequency signal processing applications since it characterizes the nonlinearity of the device, and the amount of in-band interference it generates when subject to unwanted, out-of-band signals. In this letter, we measure and model IM3 in a strain-engineered graphene mechanical resonator operated as a graphene resonant channel transistor (G-RCT). The device analyzed in this work has a voltage third-order intercept point (VIIP3) of 69.5 dBm V at a gate-to-source DC bias (Vgs) of 2.5 V, which drops to 52.1 dBm V at Vgs = 4.5 V when driven with two out-of-band input tones spaced 5 and 10 MHz from the resonant frequency. The decrease in the VIIP3 with Vgs coincides with an increase in the transmission response (S21) of the device, illustrating a trade-off between transduction efficiency and linearity. In addition, we find that conventional micro-electro-mechanical systems theory for IM3 calculation does not accurately describe our measurement data. To resolve this discrepancy, we develop a model for IM3 in G-RCTs that takes into account all of the output current terms present in the embedded transistor structure, as well as an effective Duffing parameter (αeff).
Driven similarity renormalization group: Third-order multireference perturbation theory
NASA Astrophysics Data System (ADS)
Li, Chenyang; Evangelista, Francesco A.
2017-03-01
A third-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT3) approach is presented. The DSRG-MRPT3 method has several appealing features: (a) it is intruder free, (b) it is size consistent, (c) it leads to a non-iterative algorithm with O (N6) scaling, and (d) it includes reference relaxation effects. The DSRG-MRPT3 scheme is benchmarked on the potential energy curves of F2, H2O2 , C2H6 , and N2 along the F-F, O-O, C-C, and N-N bond dissociation coordinates, respectively. The nonparallelism errors of DSRG-MRPT3 are consistent with those of complete active space third-order perturbation theory and multireference configuration interaction with singles and doubles and show significant improvements over those obtained from DSRG second-order multireference perturbation theory. Our efficient implementation of the DSRG-MRPT3 based on factorized electron repulsion integrals enables studies of medium-sized open-shell organic compounds. This point is demonstrated with computations of the singlet-triplet splitting (ΔST=ET-ES ) of 9,10-anthracyne. At the DSRG-MRPT3 level of theory, our best estimate of the adiabatic ΔST is 3.9 kcal mol-1, a value that is within 0.1 kcal mol-1 from multireference coupled cluster results.
Driven similarity renormalization group: Third-order multireference perturbation theory
Li, Chenyang; Evangelista, Francesco A.
2017-03-28
Here, a third-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT3) approach is presented. The DSRG-MRPT3 method has several appealing features: (a) it is intruder free, (b) it is size consistent, (c) it leads to a non-iterative algorithm with O(N6) scaling, and (d) it includes reference relaxation effects. The DSRG-MRPT3 scheme is benchmarked on the potential energy curves of F2, H2O2, C2H6, and N2 along the F–F, O–O, C–C, and N–N bond dissociation coordinates, respectively. The nonparallelism errors of DSRG-MRPT3 are consistent with those of complete active space third-order perturbation theory and multireference configuration interaction with singlesmore » and doubles and show significant improvements over those obtained from DSRG second-order multireference perturbation theory. Our efficient implementation of the DSRG-MRPT3 based on factorized electron repulsion integrals enables studies of medium-sized open-shell organic compounds. This point is demonstrated with computations of the singlet-triplet splitting (ΔST = ET–ES) of 9,10-anthracyne. At the DSRG-MRPT3 level of theory, our best estimate of the adiabatic ΔST is 3.9 kcal mol–1, a value that is within 0.1 kcal mol–1 from multireference coupled cluster results.« less
Measurement of third order nonlinear susceptibilities by surface plasmons
NASA Astrophysics Data System (ADS)
Chen, Y. J.; Carter, G. M.
1982-08-01
A simple technique of measuring both the magnitude and the sign of the degenerate third order nonlinear susceptibility is demonstrated. It is pointed out that since the nonlinear interaction takes place at the interface, the technique can be used to study both bulk and thin film materials, in particular those of technological importance (such as epilayers and thin-film materials overcoated on the metal grating surface). What is more, the Si results demonstrate that the technique can be used in the wavelength region where the nonlinear medium is absorbing. This suggests the possibility of using this technique to study the resonant enhancement of the third-order nonlinear susceptibility near an absorption edge. It is pointed out that although the experiments described here use only a single laser beam, it is possible to explore the nondegenerate chi-3 (omega-1, omega-2, omega-3) by this technique using laser beams at different frequencies. It is also noted that, in principle, this nonlinear coupling effect could also be observed in a similar fashion in waveguide systems.
Driven similarity renormalization group: Third-order multireference perturbation theory.
Li, Chenyang; Evangelista, Francesco A
2017-03-28
A third-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT3) approach is presented. The DSRG-MRPT3 method has several appealing features: (a) it is intruder free, (b) it is size consistent, (c) it leads to a non-iterative algorithm with O(N(6)) scaling, and (d) it includes reference relaxation effects. The DSRG-MRPT3 scheme is benchmarked on the potential energy curves of F2, H2O2, C2H6, and N2 along the F-F, O-O, C-C, and N-N bond dissociation coordinates, respectively. The nonparallelism errors of DSRG-MRPT3 are consistent with those of complete active space third-order perturbation theory and multireference configuration interaction with singles and doubles and show significant improvements over those obtained from DSRG second-order multireference perturbation theory. Our efficient implementation of the DSRG-MRPT3 based on factorized electron repulsion integrals enables studies of medium-sized open-shell organic compounds. This point is demonstrated with computations of the singlet-triplet splitting (ΔST=ET-ES) of 9,10-anthracyne. At the DSRG-MRPT3 level of theory, our best estimate of the adiabatic ΔST is 3.9 kcal mol(-1), a value that is within 0.1 kcal mol(-1) from multireference coupled cluster results.
Maxwell's second- and third-order equations of transfer for non-Maxwellian gases
NASA Technical Reports Server (NTRS)
Baganoff, D.
1992-01-01
Condensed algebraic forms for Maxwell's second- and third-order equations of transfer are developed for the case of molecules described by either elastic hard spheres, inverse-power potentials, or by Bird's variable hard-sphere model. These hardly reduced, yet exact, equations provide a new point of origin, when using the moment method, in seeking approximate solutions in the kinetic theory of gases for molecular models that are physically more realistic than that provided by the Maxwell model. An important by-product of the analysis when using these second- and third-order relations is that a clear mathematical connection develops between Bird's variable hard-sphere model and that for the inverse-power potential.
Optical transmission through generalized third-order Fibonacci multilayers
NASA Astrophysics Data System (ADS)
Hu, Xubo; Yang, Xiangbo; Liu, Songhao
2014-06-01
In this paper, by means of three kinds of methods we study the transmission properties of the light through the quasiperiodic multilayers vertically following the generalized third-order Fibonacci (GTOF) sequences. By means of the decomposition-substitution (DS) method we predict that the GTOF systems possess an interesting four-cycle transmissive characteristic at the central wavelength. Based on the electromagnetic wave theory, we then deduce the formulae of propagation matrices and transmission coefficients analytically at the central wavelength and obtain the numerical simulation results at the same time. The results obtained by three kinds of methods accord with each other and three kinds of methods are complementary. The cyclic transmissive characteristics may be useful for the designing of some optical memories, optical logical gates, and other optical controlling devices.
Testing quantum mechanics using third-order correlations
NASA Astrophysics Data System (ADS)
Kinsler, Paul
1996-04-01
Semiclassical theories similar to stochastic electrodynamics are widely used in optics. The distinguishing feature of such theories is that the quantum uncertainty is represented by random statistical fluctuations. They can successfully predict some quantum-mechanical phenomena; for example, the squeezing of the quantum uncertainty in the parametric oscillator. However, since such theories are not equivalent to quantum mechanics, they will not always be useful. Complex number representations can be used to exactly model the quantum uncertainty, but care has to be taken that approximations do not reduce the description to a hidden variable one. This paper helps show the limitations of ``semiclassical theories,'' and helps show where a true quantum-mechanical treatment needs to be used. Third-order correlations are a test that provides a clear distinction between quantum and hidden variable theories in a way analogous to that provided by the ``all or nothing'' Greenberger-Horne-Zeilinger test of local hidden variable theories.
Photographic evidence for the third-order rainbow.
Grossmann, Michael; Schmidt, Elmar; Haussmann, Alexander
2011-10-01
The first likely photographic observation of the tertiary rainbow caused by sunlight in the open air is reported and analyzed. Whereas primary and secondary rainbows are rather common and easily seen phenomena in atmospheric optics, the tertiary rainbow appears in the sunward side of the sky and is thus largely masked by forward scattered light. Up to now, only a few visual reports and no reliable photographs of the tertiary rainbow are known. Evidence of a third-order rainbow has been obtained by using image processing techniques on a digital photograph that contains no obvious indication of such a rainbow. To rule out any misinterpretation of artifacts, we carefully calibrated the image in order to compare the observed bow's angular position and dispersion with those predicted by theory.
Third order LPF type compensator for flexible rotor suspension
NASA Technical Reports Server (NTRS)
Matsushita, Osami; Takahashi, Naohiko; Takagi, Michiyuki
1994-01-01
The tuning job of the compensator for levitating flexible rotors supported by active magnetic bearings (AMB) concerns providing a good damping effect to the critical speed modes while avoiding the spillover problem on the instability of higher bending modes. In this paper, an idea for design of the control law of the compensator based on utilizing a third order low pass filter (LPF) is proposed to essentially enable elimination of the spillover instability. According to the proposed design method, good damping effects for the critical speeds are obtained by the usual phase lead/lag function. Stabilization for all of higher bending modes is completed by the additional function of the 3rd order LPF due to its phase lag approaching about -270 degrees in the high frequency domain. This idea is made clear by experiments and simulations.
Einstein-Weyl spaces and third-order differential equations
NASA Astrophysics Data System (ADS)
Tod, K. P.
2000-08-01
The three-dimensional null-surface formalism of Tanimoto [M. Tanimoto, "On the null surface formalism," Report No. gr-qc/9703003 (1997)] and Forni et al. [Forni et al., "Null surfaces formation in 3D," J. Math Phys. (submitted)] are extended to describe Einstein-Weyl spaces, following Cartan [E. Cartan, "Les espaces généralisées et l'integration de certaines classes d'equations différentielles," C. R. Acad. Sci. 206, 1425-1429 (1938); "La geometria de las ecuaciones diferenciales de tercer order," Rev. Mat. Hispano-Am. 4, 1-31 (1941)]. In the resulting formalism, Einstein-Weyl spaces are obtained from a particular class of third-order differential equations. Some examples of the construction which include some new Einstein-Weyl spaces are given.
Third-order optical nonlinearities of PVP/Pd nanohybrids
NASA Astrophysics Data System (ADS)
Papagiannouli, I.; Potamianos, D.; Krasia-Christoforou, T.; Couris, S.
2017-10-01
Pd nanoparticles stabilized by polyvinylpyrrolidone were synthesized following mild reduction of palladium ion complexes. Their morphology and optical properties were characterized using Transmission Electron Microscopy, Dynamic Light Scattering and UV-Vis absorption spectroscopy to confirm the existence of monodispersed, low-dimensional single nanoparticles. Furthermore, their third-order nonlinear optical properties were investigated by means of the Z-scan technique, using 35 ps and 4 ns laser pulses, both in the visible (532 nm) and in the infrared (1064 nm). These results denote that the surface plasmon resonance is not significantly contributing to the nonlinear optical response of Pd nanoparticles. In contrast, a two photon absorption process was found to contribute to the observed response. The present results are discussed and compared with previous literature findings.
Ultrafast third-order nonlinear optical response of pyrene derivatives
NASA Astrophysics Data System (ADS)
Shi, Yufang; Li, Zhongguo; Fang, Yu; Sun, Jinyu; Zhao, Minggen; Song, Yinglin
2017-05-01
Two mono-substituted pyrene derivatives with delocalized electron system 1-(pyren-1-yl)-3-(4-Methyl thiophene-2-yl) acrylic ketone (13#) and 1-(pyren-1-yl)-3-(4-bromo thiophene-2-yl) acrylic ketone (15#) were successfully synthesized. The resultant compounds were characterized by nuclear magnetic resonance (NMR), infrared spectroscopy (IR), high resolution mass spectrum (HR-MS), and UV-vis spectra. The third-order nonlinear optical properties of the compounds were investigated using Z-scan technique with femtosecond laser pulses at 500 nm and 700 nm, respectively. Both of the compounds showed a decrease in transmittance about the focus, which are typical of two-photon absorption. It was found that the two-photon absorption behavior of the pyrene derivatives were modified by substituents on thiophene ring. These results indicate that both compounds can be promising candidates for future optoelectronic and bio-imaging applications.
New Third-Order Moments for the PBL
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Cheng, Y.; Howard, A.; Hansen, James E. (Technical Monitor)
2000-01-01
Turbulent convection is inherently non-local and a primary condition for a successful treatment of the PBL is a reliable model of non-locality. In the dynamic equations governing the convective flux, turbulent kinetic energy, etc, non-locality enters through the third-order moments, TOMs. Since the simplest form, the so-called down gradient approximation (DGA , severely underestimates the TOMs (by up to an order of magnitude), a more physical model is needed. In 1994, an analytical model was presented which was derived directly from the dynamical equations for the TOMs. It considerably improved the DGA but was a bit cumbersome to use. Here, we present a new analytic expression for the TOMs which is considerably simpler than the 1994 expression and which at the same time yields a much better fit to the LES data.
On smoothness property of third-order differential operator
NASA Astrophysics Data System (ADS)
Ospanov, Kordan N.; Yeskabylova, Zhuldyz B.
2017-09-01
In the Hilbert space, we consider the minimal third order degenerate differential operator L0 with unbounded second order intermediate coefficient r. L0 is not the semibounded operator: its domain is not subspace of some Sobolev space. L0 type operators appear in the physics of the solid and atmosphere and in the electrohydrodynamics. In addition, this operator describes the propagation of a radial pulse wave and processes occurring in an environment capable of keeping information, and it is found in some spectral problems. We assume that |r| strongly increases at infinity and weakly oscillates. Using method of separability theory and the weighted Hardy type inequalities, we find the sufficient conditions to r, under which L0 is closable, and its closure L is the bounded invertible and separable operator.
Third-order phase transition in random tilings
NASA Astrophysics Data System (ADS)
Colomo, F.; Pronko, A. G.
2013-10-01
We consider the domino tilings of an Aztec diamond with a cut-off corner of macroscopic square shape and given size and address the bulk properties of tilings as the size is varied. We observe that the free energy exhibits a third-order phase transition when the cut-off square, increasing in size, reaches the arctic ellipse—the phase separation curve of the original (unmodified) Aztec diamond. We obtain this result by studying the thermodynamic limit of a certain nonlocal correlation function of the underlying six-vertex model with domain wall boundary conditions, the so-called emptiness formation probability (EFP). We consider EFP in two different representations: as a τ function for Toda chains and as a random matrix model integral. The latter has a discrete measure and a linear potential with hard walls; the observed phase transition shares properties with both Gross-Witten-Wadia and Douglas-Kazakov phase transitions.
Third-order elastic solution of the stress field around a wellbore
Elata, D.
1996-04-01
Within a certain range of strain, consolidated granular materials may be characterized as nonlinear elastic solids. The nonlinearity can be easily observed by examining the effect of stress on the acoustical properties of the material. Ignoring damage evolution and failure that occur in higher strains and the hysteretic behavior due to intercyranular friction, the material can be modeled as a nonlinear hyperelastic solid. A simple example of such a model is formulating the strain energy as a third-order polynomial of the strain invariants. This model is limited in the sense that the material is assumed to be isotropic with respect to the stress free state, and that the mechanical response of the material is described by only five material constants. Nevertheless, this model is appealing because it naturally exhibits stress dependent stiffness and stress induced anisotropy, and it allows a different mechanical response to positive and negative volume changes. In this work, this model is used to calculate the stress field around a wellbore. Many well logging tools use acoustics (e.g., tube, surface, torsion, and flexural waves) to detect pore fluids and ore in the surrounding granular rock. By modeling the rock as an isotropic third-order elastic material the effects of the inhomogeneous stiffness and the stress induced anisotropy may be examined. Analysis of the tangential stress around a wellbore in an isotropic third-order elastic (TOE) material yields different results than the same analysis in the related isotropic linear elastic (LE) material (i.e., both materials have the same stiffness tensor at the stress free state). This difference modifies the far-field stress that is interpreted of from hydraulic fracturing data. The analysis in the present work is static and pore fluid effects are ignored.
Third-Order Optical Nonlinear Properties of Polymers.
NASA Astrophysics Data System (ADS)
Yang, Lina
The development of polymers as nonlinear optical materials coincide with a renewed interest in the field of nonlinear optics, and its applications for the future photonic devices. Large nonresonant susceptibilities, fast electronic responses, and ease of processing make polymers one of the best candidates for the applications. This thesis describes the study of the third order optical nonlinear properties in polymers. The studies have been focused on two classes of conjugated polymers: the pi-electron system and the sigma-electron system. Important parameters which fully characterize the nonlinearities of materials, such as magnitude, response time, and the sign of chi^{(3)} have been measured. Various mechanisms responsible for the observed nonlinearities have also been investigated. The thesis consists of twelve chapters. The first two chapters provide an overview of the fundamental aspects of nonlinear optics, optical properties of polymers, and the experimental techniques, apparatus which can be used to investigate the third order optical nonlinearities of polymers, such as the degenerate four wave mixing and the single beam Z-scan technique. The pi-electron polymer systems are studied in Chapters III to VII. We have investigated the nonlinearities in polyacetylene, polydiacetylene, as well as in a relatively new material-polythiophenes. Most of the work has been concentrated on polythiophenes. For the first time, the spectrum of the nonlinear coefficient chi^3 covering the single photon transition band has been measured in polythiophene. The experimental results show that chi^3 is large (>10^{ -9}esu) and fast (<15ps) above gap. The real part of chi^3 has also been found to be negative at both 532 and 1064 nm. The single photon resonance is responsible for the negative chi^3 at 532 nm, while two photon resonant absorption is responsible for the negative chi^3 at 1064 nm. For the first time, the enhancement of chi ^{(3)} was observed about photoinduced
Transmission Measurement of the Third-Order Susceptibility of Gold
NASA Technical Reports Server (NTRS)
Smith, David D.; Yoon, Youngkwon; Boyd, Robert W.; Crooks, Richard M.; George, Michael
1999-01-01
Gold nanoparticle composites are known to display large optical nonlinearities. In order to assess the validity of generalized effective medium theories (EMT's) for describing the linear and nonlinear optical properties of metal nanoparticle composites, knowledge of the linear and nonlinear susceptibilities of the constituent materials is a prerequisite. In this study the inherent nonlinearity of the metal is measured directly (rather than deduced from a suitable EMT) using a very thin gold film. Specifically, we have used the z-scan technique at a wavelength near the transmission window of bulk gold to measure the third-order susceptibility of a continuous thin gold film deposited on a quartz substrate surface-modified with a self-assembled monolayer to promote adhesion and uniformity without affecting the optical properties. We compare our results with predictions which ascribe the nonlinear response to a Fermi-smearing mechanism. Further, we note that the sign of the nonlinear susceptibility is reversed from that of gold nanoparticle composites.
Transmission Measurement of the Third-Order Susceptibility of Gold
NASA Technical Reports Server (NTRS)
Smith, David D.; Yoon, Youngkwon; Boyd, Robert W.; Crooks, Richard M.; George, Michael
1999-01-01
Gold nanoparticle composites are known to display large optical nonlinearities. In order to assess the validity of generalized effective medium theories (EMT's) for describing the linear and nonlinear optical properties of metal nanoparticle composites, knowledge of the linear and nonlinear susceptibilities of the constituent materials is a prerequisite. In this study the inherent nonlinearity of the metal is measured directly (rather than deduced from a suitable EMT) using a very thin gold film. Specifically, we have used the z-scan technique at a wavelength near the transmission window of bulk gold to measure the third-order susceptibility of a continuous thin gold film deposited on a quartz substrate surface-modified with a self-assembled monolayer to promote adhesion and uniformity without affecting the optical properties. We compare our results with predictions which ascribe the nonlinear response to a Fermi-smearing mechanism. Further, we note that the sign of the nonlinear susceptibility is reversed from that of gold nanoparticle composites.
Effect of vorticity on second- and third-order statistics of passive scalar gradients.
Gonzalez, Michel
2002-05-01
The influence of vorticity on second- and third-order moments of the spatial derivatives of a forced, passive scalar field has been studied in the framework of a simplified problem; the analysis is restricted to dominating rotation and molecular diffusion is represented by a linear model. The results reveal that, in the case of a passive scalar experiencing forcing in an isotropic medium, both vorticity and diffusion counteract anisotropy imposed on the scalar field. Anisotropy at the level of second-order moments appears to be destroyed essentially by the action of vorticity.
Second and third order nonlinear optical properties of conjugated molecules and polymers
NASA Technical Reports Server (NTRS)
Perry, Joseph W.; Stiegman, Albert E.; Marder, Seth R.; Coulter, Daniel R.; Beratan, David N.; Brinza, David E.
1988-01-01
Second- and third-order nonlinear optical properties of some newly synthesized organic molecules and polymers are reported. Powder second-harmonic-generation efficiencies of up to 200 times urea have been realized for asymmetric donor-acceptor acetylenes. Third harmonic generation chi(3)s have been determined for a series of small conjugated molecules in solution. THG chi(3)s have also been determined for a series of soluble conjugated copolymers prepared using ring-opening metathesis polymerization. The results are discussed in terms of relevant molecular and/or macroscopic structural features of these conjugated organic materials.
NASA Astrophysics Data System (ADS)
Werncke, W.; Pfeiffer, M.; Johr, T.; Lau, A.; Grahn, W.; Johannes, H.-H.; Dähne, L.
1997-04-01
The chain length dependencies of the static third order hyperpolarizabilities γSTAT for the homologous series of benzthiacyanine dyes and of simple bis(dimethylamino)methine dyes were extrapolated from nondegenerate four wave mixing dispersion measurements and compared with theoretical values. Up to the heptamethine the π-electron contributions γSTATπ of both homologous series show a similar increase with the growing number of π-electrons ( N) of the chain ( γSTATπ ˜ - N8 ± 2). However, the absolute values of the benzthiacyanines are considerable higher than of the corresponding bis(dimethylamino)methines. Negative valued hyperpolarizabilities γSTATπ in the homologous series increasing up to γSTATπ = - 850 × 10 -36 esu were determined. For the first time a saturation of the nonlinearity could be observed experimentally in the series of benzthiacyanines for the longest chain (benzthicyanine nonamethine).
Effects of third-order torque on frictional force of self-ligating brackets.
Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Ahluwalia, Karamdeep S; Kohda, Naohisa; Mizoguchi, Itaru
2014-11-01
To investigate the effects of third-order torque on frictional properties of self-ligating brackets (SLBs). Three SLBs (two passive and one active) and three archwires (0.016 × 0.022-inch nickel-titanium, and 0.017 × 0.025-inch and 0.019 × 0.025-inch stainless steel) were used. Static friction was measured by drawing archwires though bracket slots with four torque levels (0°, 10°, 20°, 30°), using a mechanical testing machine (n = 10). A conventional stainless-steel bracket was used for comparison. RESULTS were subjected to Kruskal-Wallis and Mann-Whitney U-tests. Contact between the bracket and wire was studied using a scanning electron microscope. In most bracket-wire combinations, increasing the torque produced a significant increase in static friction. Most SLB-wire combinations at all torques produced less friction than that from the conventional bracket. Active-type SLB-wire combinations showed higher friction than that from passive-type SLB-wire combinations in most conditions. When increasing the torque, more contact between the wall of a bracket slot and the edge of a wire was observed for all bracket types. Increasing torque when using SLBs causes an increase in friction, since contact between the bracket slot wall and the wire edge becomes greater; the design of brackets influences static friction.
NASA Astrophysics Data System (ADS)
Altürk, Sümeyye; Avcı, Davut; Tamer, Ömer; Atalay, Yusuf; Şahin, Onur
2016-11-01
A cobalt(II) complex of 6-methylpicolinic acid, [Co(6-Mepic)2(H2O)2]·2H2O, was prepared and fully determined by single crystal X-ray crystal structure analysis as well as FT-IR, FT-Raman. UV-vis spectra were recorded within different solvents, to illustrate electronic transitions and molecular charge transfer within complex 1. The coordination sphere of complex 1 is a distorted octahedron according to single crystal X-ray results. Moreover, DFT (density functional theory) calculations with HSEH1PBE/6-311 G(d,p) level were carried out to back up the experimental results, and form base for future work in advanced level. Hyperconjugative interactions, intramolecular charge transfer (ICT), molecular stability and bond strength were researched by the using natural bond orbital (NBO) analysis. X-ray and NBO analysis results demonsrate that O-H···O hydrogen bonds between the water molecules and carboxylate oxygen atoms form a 2D supramolecular network, and also adjacent 2D networks connected by C-H···π and π···π interactions to form a 3D supramolecular network. Additionally, the second- and third-order nonlinear optical parameters of complex 1 were computed at DFT/HSEH1PBE/6-311 G(d,p) level. The refractive index (n) was calculated by using the Lorentz-Lorenz equation in order to investigate polarization behavior of complex 1 in different solvent polarities. The first-order static hyperpolarizability (β) value is found to be lower than pNA value because of the inversion symmetry around Co (II). But the second-order static hyperpolarizability (γ) value is 2.45 times greater than pNA value (15×10-30 esu). According to these results, Co(II) complex can be considered as a candidate to NLO material. Lastly molecular electrostatic potential (MEP), frontier molecular orbital energies and related molecular parameters for complex 1 were evaluated.
Static longitudinal dielectric function of model molecular fluids
NASA Astrophysics Data System (ADS)
Raineri, Fernando O.; Resat, Haluk; Friedman, Harold L.
1992-02-01
The static longitudinal dielectric function ɛL(k) is calculated for several polar interaction site model (ISM) fluids for comparison with related models having arbitrary short-range interactions and a set of one or more lower-order multipole moments at the centers (ΩM models). The requisite averages over the ISM fluids are calculated by the extended reference interaction site method (XRISM) using site-site hypernetted chain (HNC)-like closures modified to reproduce the correct long-range behavior of the site-site pair correlation functions. They are compared with averages over the ΩM models under the RHNC theory taken from the literature or calculated under the mean spherical approximation. We find for fluids of strong enough polarity that ɛL(k) is negative over a finite range of k, the low end being in agreement with recent computer simulation studies of both ISM and ΩM polar fluids. However, we confirm that the expected large-k behavior ɛL(k)=1 governs the ISMs, but not the ΩM models. Based on an adaptation of the color charge-color field techniques of molecular dynamics, we develop the concept of the color longitudinal dielectric function; it provides useful information about the role of the spatial extent of the molecular charge distribution on the behavior of ɛL(k). The ISM fluids we have analyzed include dipolar dumbbells over a wide range of bond length and polarity as well as realistic interaction site models for water and methanol. For the methanol model, we compare our ɛL(k) with recent computer simulation results and find substantial agreement.
NASA Astrophysics Data System (ADS)
Wang, Chao; Yuan, Yizhong; Tian, Xiaohui; Sun, Jinyu; Shao, Hongjuan; Sun, Zhenrong
2013-09-01
The linear and third-order nonlinear optical properties of four polymethine cyanines (PC-1-PC-4) were investigated by UV-visible absorption spectroscopy and degenerate four-wave mixing (DFWM) technique. The second-order hyperpolarizabilities γ of the four chromophores achieve 10-31 esu. The dependence of their third-order optical nonlinearities on the molecular structure was discussed based on density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. The calculated second-order hyperpolarizabilities γ well-reproduce the experimental trends. The results show that the third-order optical nonlinearities of the chromophores can be drastically enhanced by bulky heteroatom (such as selenium) with low electro-negativity, or extended π-conjugated terminal group.
Interplay between Graph Topology and Correlations of Third Order in Spiking Neuronal Networks.
Jovanović, Stojan; Rotter, Stefan
2016-06-01
The study of processes evolving on networks has recently become a very popular research field, not only because of the rich mathematical theory that underpins it, but also because of its many possible applications, a number of them in the field of biology. Indeed, molecular signaling pathways, gene regulation, predator-prey interactions and the communication between neurons in the brain can be seen as examples of networks with complex dynamics. The properties of such dynamics depend largely on the topology of the underlying network graph. In this work, we want to answer the following question: Knowing network connectivity, what can be said about the level of third-order correlations that will characterize the network dynamics? We consider a linear point process as a model for pulse-coded, or spiking activity in a neuronal network. Using recent results from theory of such processes, we study third-order correlations between spike trains in such a system and explain which features of the network graph (i.e. which topological motifs) are responsible for their emergence. Comparing two different models of network topology-random networks of Erdős-Rényi type and networks with highly interconnected hubs-we find that, in random networks, the average measure of third-order correlations does not depend on the local connectivity properties, but rather on global parameters, such as the connection probability. This, however, ceases to be the case in networks with a geometric out-degree distribution, where topological specificities have a strong impact on average correlations.
Nakano, Masayoshi; Kishi, Ryohei; Yoneda, Kyohei; Inoue, Yudai; Inui, Tomoya; Shigeta, Yasuteru; Kubo, Takashi; Champagne, Benoît
2011-08-11
The third-order nonlinear optical (NLO) properties, at the molecular level, the static second hyperpolarizabilities, γ, of supermolecular systems composed of phenalenyl and pyrene rings linked by acetylene units are investigated by employing the long-range corrected spin-unrestricted density functional theory, LC-UBLYP, method. The phenalenyl based superethylene, superallyl, and superbutadiene in their lowest spin states have intermediate diradical characters and exhibit larger γ values than the closed-shell pyrene based superpolyene systems. The introduction of a positive charge into the phenalenyl based superallyl radical changes the sign of γ and enhances its amplitude by a factor of 35. Although such sign inversion is also observed in the allyl radical and cation systems in their ground state equilibrium geometries, the relative amplitude of γ is much different, that is, |γ(regular allyl cation)/γ(regular allyl radical)| = 0.61 versus |γ(phenalenyl based superallyl cation)/γ(phenalenyl based superallyl radical)| = 35. In contrast, the model ethylene, allyl radical/cation, and butadiene systems with stretched carbon-carbon bond lengths (2.0 Å), having intermediate diradical characters, exhibit similar γ features to those of the phenalenyl based superpolyene systems. This exemplifies that the size dependence of γ as well as its sign change by introducing a positive charge on the phenalenyl based superpolyene systems originate from their intermediate diradical characters. In addition, the change from the lowest to the highest π-electron spin states significantly reduces the γ amplitudes of the neutral phenalenyl based superpolyene systems. For phenalenyl based superallyl cation, the sign inversion of γ (from negative to positive) is observed upon switching between the singlet and triplet states, which is predicted to be associated with a modification of the balance between the positive and negative contributions to γ. The present study paves the way
A digital-to-analog conversion circuit using third-order polynomial interpolation
NASA Technical Reports Server (NTRS)
Dotson, W. P., Jr.; Wilson, J. H.
1972-01-01
Zero- and third-order digital-to-analog conversion techniques are described, and the theoretical error performances are compared. The design equations and procedures for constructing a third-order digital-to-analog converter by using analog design elements are presented. Both a zero- and a third-order digital-to-analog converter were built, and the performances are compared with various signal inputs.
Quadrupole contribution to the third-order optical activity spectroscopy
NASA Astrophysics Data System (ADS)
Choi, Jun-Ho; Cho, Minhaeng
2007-07-01
Time-resolved nonlinear optical activity measurement spectroscopy can be a useful tool for studying biomolecular and chemical reaction dynamics of chiral molecules. Only recently, the two-dimensional (2D) circularly polarized photon echo (CP-PE) spectroscopy of polypeptides and a photosynthetic light-harvesting complex were discussed, where the beam configuration was specifically controlled in such a way to eliminate the quadrupole contribution to the CP-PE signal. In this paper, we generalize the CP-PE spectroscopy by including the transition quadrupole contributions from peptide amide I vibrational transition and chlorophyll electronic transition. By using a density functional theory calculation method, the corresponding amide I vibrational and chlorophyll Qy electronic transition quadrupole tensor elements are determined. Amplitude of nonlinear optical transition pathway involving a quadrupole transition is found to be comparable to those of magnetic dipole terms for two different cases considered, i.e., dipeptides and photosynthetic antenna complex. However, due to the rotational averaging factors, the overall quadrupole contribution is an order of magnitude smaller than the magnetic dipole contribution. This suggests that the conventional 2D photon echo method and experimental scheme can be directly used to measure the 2D CP-PE signal from proteins and molecular complexes and that the 2D CP-PE signal is mainly dictated by the magnetic dipole contribution.
Quadrupole contribution to the third-order optical activity spectroscopy.
Choi, Jun-Ho; Cho, Minhaeng
2007-07-14
Time-resolved nonlinear optical activity measurement spectroscopy can be a useful tool for studying biomolecular and chemical reaction dynamics of chiral molecules. Only recently, the two-dimensional (2D) circularly polarized photon echo (CP-PE) spectroscopy of polypeptides and a photosynthetic light-harvesting complex were discussed, where the beam configuration was specifically controlled in such a way to eliminate the quadrupole contribution to the CP-PE signal. In this paper, we generalize the CP-PE spectroscopy by including the transition quadrupole contributions from peptide amide I vibrational transition and chlorophyll electronic transition. By using a density functional theory calculation method, the corresponding amide I vibrational and chlorophyll Q(y) electronic transition quadrupole tensor elements are determined. Amplitude of nonlinear optical transition pathway involving a quadrupole transition is found to be comparable to those of magnetic dipole terms for two different cases considered, i.e., dipeptides and photosynthetic antenna complex. However, due to the rotational averaging factors, the overall quadrupole contribution is an order of magnitude smaller than the magnetic dipole contribution. This suggests that the conventional 2D photon echo method and experimental scheme can be directly used to measure the 2D CP-PE signal from proteins and molecular complexes and that the 2D CP-PE signal is mainly dictated by the magnetic dipole contribution.
Phase-dependent ultrafast third-order optical nonlinearities in metallophthalocyanine thin films
NASA Astrophysics Data System (ADS)
Kumar, Samir; Anil Kumar, K. V.; Dharmaprakash, S. M.; Das, Ritwick
2016-09-01
We present a comprehensive study on the impact of phase transformations of metallophthalocyanine thin films on their third-order nonlinear optical (NLO) properties. The metallophthalocyanine thin films are prepared by thermally evaporating the commercially available Copper(II)2,9,16,23-Tetra-tert-butyl-29H,31H-phthalocyanine (CuPc) and Zinc(II) 2,9,16,23-Tetra-tert-butyl-29H,31H-phthalocyanine (ZnPc) powder on glass substrate. Thermal annealing causes a phase transformation which has a distinct signature in powder X-ray diffraction and UV-Vis-NIR spectroscopy. The NLO characteristics which include nonlinear refractive index n2, as well as nonlinear absorption coefficient (βeff), were measured by using a single beam Z-scan technique. An ultrashort pulsed fiber laser emitting femtosecond pulses (Δτ ≈ 250 fs) at 1064 nm central wavelength is used as a source for the Z-scan experiment. The βeff values in as prepared thin films were ascertained to be smaller as compared to the annealed one due to the smaller value of saturation intensity (Is) which, in turn, is a consequence of ground-state bleaching in the thermally unstable amorphous state of the molecule. Interestingly, the nonlinear refractive indices bear opposite sign for CuPc and ZnPc. The variations in the third-order nonlinearity in CuPc and ZnPc are discussed in terms of molecular packing and geometries of metallophthalocyanine molecules.
NASA Astrophysics Data System (ADS)
Castro, Adailton N.; Almeida, Leonardo R.; Anjos, Murilo M.; Oliveira, Guilherme R.; Napolitano, Hamilton B.; Valverde, Clodoaldo; Baseia, Basílio
2016-06-01
Coumarin derivatives exist widely in nature and show a wide range of biological activities such as anti-inflammatory, anti-oxidative and anti-cancer. The structure of C11H7BrO3 has been redetermined using 3330 measured reflections with 1666 unique [Rint = 0.0088] with final indices R1 = 0.0128 [I > 2σ(I)] and wR2 = 0.0347 (all data). The bromocoumarin molecule is almost planar and has three planar dimers stabilized by interaction of type Csbnd H⋯Br and Csbnd H⋯O, which form parallel layers connected via several π-π interactions [centroid-centroid distances = 3.958(1) Å]. To provide a view of the non-linear optical behavior of third order of the crystal bromocoumarin in both cases static and dynamic, we calculate the linear polarizability (α) and the second hyperpolarizability (γ) using a new supermolecule approach combined with an iterative electrostatic scheme where the neighboring molecules are represented by point charges. The results of calculations of the HOMO and LUMO energies show the occurrence of charge transfer inside the molecule. The computational results of the second (static and dynamics) hyperpolarizabilities show the molecule exhibiting second hyperpolarizability with values different of zero, which implies a third order microscopic behavior.
Static and shock compressibility of TATB molecular crystal
NASA Astrophysics Data System (ADS)
Degtyarev, A. A.; Smirnov, E. B.; Kostitsin, O. V.; Stankevich, A. V.; Muzyrya, A. K.; Ten, K. A.; Pruuel, E. R.; Kashkarov, A. O.; Batretdinova, L. H.
2016-11-01
The paper presents analysis of experimental data on hydrostatic and shock-wave compression of TATB energy-saturated material. The semi-empirical Mie-Grüneisen equation of state was used to describe thermodynamic properties of metastable molecular crystals without considering phase transitions. The equation of state describes experimental data on isothermal compression of a molecular crystal, and this data are obtained using the powder diffraction method. The Hugoniot curve expression plausibly describes shock-compression data on the studied material having various initial porosities.
OTRA based second and third order sinusoidal oscillators and their phase noise performance
NASA Astrophysics Data System (ADS)
Komanapalli, Gurumurthy; Pandey, Neeta; Pandey, Rajeshwari
2017-07-01
In this paper operational transresistance amplifier (OTRA) based second and third order sinusoidal oscillators are proposed. The proposed second order oscillator is designed using single OTRA based Sallen Key low pass filter structure and third order oscillator is obtained by cascading three low pass filters and placing in a loop. The non-ideality and phase noise analyses of the circuits are also presented with necessary mathematical formulations. Workability of the proposed oscillators are verified through PSPICE simulations using 0.18µm AGILENT CMOS process parameters. The total harmonic distortion (THD) for proposed second order and third order oscillators are found as 3.27% and 0.631% respectively.
Green synthesis and third-order nonlinear optical properties of 6-(9H-carbazol-9-yl) hexyl acetate
NASA Astrophysics Data System (ADS)
Chen, Baili; Geng, Feng; Luo, Xuan; Zhong, Quanjie; Zhang, Qingjun; Fang, Yu; Huang, Chuanqun; Yang, Ruizhuang; Shao, Ting; Chen, Shufan
2016-10-01
An extremely simple and green approach for the synthesis of photoelectric material 6-(9H-carbazol-9-yl) hexy-acetate (CHA) has been described in detail. The molecular structure of CHA was identified with Fourier transform infrared (FT-IR) spectra and 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy. The optical absorption of CHA was recorded using ultraviolet-visible (UV-vis) spectrum. Notably, the reaction was accomplished in water medium instead of traditional toxic solvents (e.g., benzene and chloroform). The yield of CHA is up to 99%, which is increased by 13% compared with the traditional method. The approach developed by us makes it possible to achieve commercial production of CHA. Moreover, the thermal stability of CHA was studied with thermogravimetric (TG) and derivative thermogravimetric (DTG) method. The third-order nonlinear optical (NLO) properties of CHAn (obtained by new method) and CHAt (obtained by traditional method) have been studied by a Z-scan technique at 440 nm. The thermal decomposition temperature is above 200 °C. The third-order NLO of CHAn and CHAt are the same. The third-order NLO susceptibility χ (3) and two photon Figures of Merit (FOMs) of CHA are 1.58 × 10-8 (esu) and 4.55, respectively. The results reveal that CHA may be a promising candidate for all-optical switching application.
Resonant-type third-order optical nonlinearity and optical bandgap in multicomponent oxide glasses
El-Diasty, Fouad; Abdel-Baki, Manal; Bakry, Assem M.
2009-05-01
Optical nonlinearity or the nonlinear hyperpolarizability of amorphous materials (e.g., glasses) is related directly to the complex third-order susceptibility. The imaginary part of third-order susceptibility affects negatively the maximum data rate in telecommunication systems. In addition, many transition metals containing glasses have bandgaps with semiconductor-like behavior. So, due to the necessity of operation near the absorption band edge, the study of optical nonlinearity and band structure in glasses is very essential. In this work, we investigated the relationship between the imaginary third-order nonlinear susceptibility and the bandgap of some different series of prepared oxide glasses. A universal empirical formula is given to correlate the imaginary part of the third-order nonlinear susceptibility of the glasses and their optical bandgaps. The obtained nonlinearity is discussed in view of available theories and mechanisms.
Resonant-type third-order optical nonlinearity and optical bandgap in multicomponent oxide glasses.
el-Diasty, Fouad; Abdel-Baki, Manal; Bakry, Assem M
2009-05-01
Optical nonlinearity or the nonlinear hyperpolarizability of amorphous materials (e.g., glasses) is related directly to the complex third-order susceptibility. The imaginary part of third-order susceptibility affects negatively the maximum data rate in telecommunication systems. In addition, many transition metals containing glasses have bandgaps with semiconductor-like behavior. So, due to the necessity of operation near the absorption band edge, the study of optical nonlinearity and band structure in glasses is very essential. In this work, we investigated the relationship between the imaginary third-order nonlinear susceptibility and the bandgap of some different series of prepared oxide glasses. A universal empirical formula is given to correlate the imaginary part of the third-order nonlinear susceptibility of the glasses and their optical bandgaps. The obtained nonlinearity is discussed in view of available theories and mechanisms.
Z-scan: A simple technique for determination of third-order optical nonlinearity
Singh, Vijender; Aghamkar, Praveen
2015-08-28
Z-scan is a simple experimental technique to measure intensity dependent nonlinear susceptibilities of third-order nonlinear optical materials. This technique is used to measure the sign and magnitude of both real and imaginary part of the third order nonlinear susceptibility (χ{sup (3)}) of nonlinear optical materials. In this paper, we investigate third-order nonlinear optical properties of Ag-polymer composite film by using single beam z-scan technique with Q-switched, frequency doubled Nd: YAG laser (λ=532 nm) at 5 ns pulse. The values of nonlinear absorption coefficient (β), nonlinear refractive index (n{sub 2}) and third-order nonlinear optical susceptibility (χ{sup (3)}) of permethylazine were found to be 9.64 × 10{sup −7} cm/W, 8.55 × 10{sup −12} cm{sup 2}/W and 5.48 × 10{sup −10} esu, respectively.
Role of intensity fluctuations in third-order correlation double-slit interference of thermal light.
Chen, Xi-Hao; Chen, Wen; Meng, Shao-Ying; Wu, Wei; Wu, Ling-An; Zhai, Guang-Jie
2013-07-01
A third-order double-slit interference experiment with a pseudothermal light source in the high-intensity limit has been performed by actually recording the intensities in three optical paths. It is shown that not only can the visibility be dramatically enhanced compared to the second-order case as previously theoretically predicted and shown experimentally, but also that the higher visibility is a consequence of the contribution of third-order correlation interaction terms, which is equal to the sum of all contributions from second-order correlation. It is interesting that, when the two reference detectors are scanned in opposite directions, negative values for the third-order correlation term of the intensity fluctuations may appear. The phenomenon can be completely explained by the theory of classical statistical optics and is the first concrete demonstration of the influence of the third-order correlation terms.
Numerical algorithm for the third-order partial differential equation with local boundary conditions
NASA Astrophysics Data System (ADS)
Ashyralyev, Allaberen; Belakroum, Kheireddine; Guezane-Lakoud, Assia
2017-09-01
Three-step difference schemes generated by Taylor's decomposition on four points for the approximate solution of the local boundary-value problems for a third order partial differential equation are presented. Results of numerical experiments are provided.
Improving signal-to-noise ratio of fetal magnetocardiograph by third order flux transformer
NASA Astrophysics Data System (ADS)
Bachir, Wesam; Dunajski, Zbigniew
2003-10-01
The application of SQUIDS and superconducting radiometers in clinical biomagnetic instrumentation for fetal magnetocardiography is presented. The paper focuses on the characteristics and performance of the third order flux transformer for fetal magnetocardiography with a good signal to noise ratio. An optimum figure of merit of the third order flux transformer was determined. The optimal signal-to-noise ratio (SNR) was used as the optimization criterion.
Properties of solutions of third-order trinomial difference equations with deviating arguments
NASA Astrophysics Data System (ADS)
Gleska, Alina; Migda, Małgorzata
2017-07-01
The third-order nonlinear trinomial difference equation of the form Δ3xn+pnΔ xn +1+qnf (xσ (n ))=0 is studied. Rewriting this equation as a binomial third-order difference equation we establish a classification of all nonoscillatory solutions, criteria for oscillation of bounded solutions and sufficient conditions for the existence of certain types of nonoscillatory solutions of the above equation.
Ho, H. C.; Johnson, W. R.; Blundell, S. A.; Safronova, M. S.
2006-08-15
Third-order relativistic many-body perturbation theory (MBPT) is applied to obtain energies of ions with two valence electrons in the no virtual-pair approximation (NVPA). A total of 302 third-order Goldstone diagrams are organized into 12 one-body and 23 two-body terms. Only third-order two-body terms and diagrams are presented in this paper, owing to the fact that the one-body terms are identical to the previously studied third-order terms in monovalent ions. Dominant classes of diagrams are identified. The model potential is the Dirac-Hartree-Fock potential V{sup N-2}, and B-spline basis functions in a cavity of finite radius are employed in the numerical calculations. The Breit interaction is taken into account through the second order of perturbation theory, and the lowest-order Lamb shift is also evaluated. Sample calculations are performed for berylliumlike ions with Z=4-7, and for the magnesiumlike ion P IV. The third-order excitation energies are in excellent agreement with measurement with an accuracy at 0.2% level for the cases considered. Comparisons are made with second-order MBPT results, and with other calculations. The third-order energy correction is shown to be significant, improving the previous second-order calculations by an order of magnitude.
Using Static and Dynamic Visuals to Represent Chemical Change at Molecular Level
ERIC Educational Resources Information Center
Ardac, Dilek; Akaygun, Sevil
2005-01-01
The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty-two eighth graders (age range 14-15 years) participated in one of the…
Using Static and Dynamic Visuals to Represent Chemical Change at Molecular Level
ERIC Educational Resources Information Center
Ardac, Dilek; Akaygun, Sevil
2005-01-01
The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty-two eighth graders (age range 14-15 years) participated in one of the…
Li, Hai-ning; Zhang, Li-ping; Wu, Hong; Li, Xian; Ding, Liang-en
2008-06-01
The authors observed the spectrum of third-order harmonic (TH) emission of the plasma channel in atmosphere by focused ultra-short laser pulses under various conditions. The authors used pulsed Ti: sapphire chirped pulse amplification (CPA) femtosecond laser system, with the central wavelength at 795 nm, repetition rate of 10 Hz, pulse duration of 30 fs and the pulse energy of 12 mJ, focused by a concave mirror with the focal length of 0.5 m, which can generate about 10(13) W x cm(-2) of power intensity. Under this condition, the dynamic balance between nonlinear Kerr self-focusing and plasma defocusing can support a long plasma channel in the interaction of the high intense laser pulses and gaseous media, and the interaction length between the laser pulse and air is greatly elongated, which is helpful to generating third-order harmonic emission. The full width at half maximum (FWHM) of the generated third-order harmonic spectrum is 15 nm with the central wavelength at 265 nm in the forward direction. The spectra of third-order harmonic emission red shift when the laser pulse is positive chirped. On the contrary, the spectra of third-order harmonic emission blue shift when the laser pulse is negative chirped. Proper dispersion can increase the intensity of third-order harmonic spectrum peak and sharped the spectrum peak. With the group velocity dispersion (GVD) of the pulses equal to +1.3 x 10(5) fs2, the peak of third-order harmonic spectrum red shifts and the group velocity dispersion of laser pulses equals to zero fs2. The experiment shows that the rising wing of pulses can obtain higher third-order harmonic conversion efficiency than the falling edge of the pulses. In addition, acoustic-optic programmable dispersive filter (AOPDF) in the laser system can control the spectrum shape of the laser. Changing the hole position of acoustic-optic programmable dispersive filter can also shift the spectrum shape of third-order harmonic emission in a certain range
NASA Astrophysics Data System (ADS)
Toonen, Ryan C.; Cole, M. W.
2012-05-01
Using microwave reflection spectroscopy, the complex permittivities of etch defined, 240 nm thick, (Ba0.6Sr0.4)TiO3, thin films have been measured over the frequency range of (1 to 4) GHz. Anomalous electric-field-induced electro-acoustic resonances were observed and characterized as a function of extrinsic electric field magnitude, ambient temperature, and sample diameter. The real and imaginary parts of the measured permittivities were fit to frequency-dependent functions derived from the Lorentz oscillator model. From these functions, extracted static dielectric constants were found to display excellent agreement with a closed-form expression derived by calculating third-order nonlinear susceptibility from the Landau-Devonshire-Ginzberg model.
Third-order analysis of pseudopotential lattice Boltzmann model for multiphase flow
NASA Astrophysics Data System (ADS)
Huang, Rongzong; Wu, Huiying
2016-12-01
In this work, a third-order Chapman-Enskog analysis of the multiple-relaxation-time (MRT) pseudopotential lattice Boltzmann (LB) model for multiphase flow is performed for the first time. The leading terms on the interaction force, consisting of an anisotropic and an isotropic term, are successfully identified in the third-order macroscopic equation recovered by the lattice Boltzmann equation (LBE), and then new mathematical insights into the pseudopotential LB model are provided. For the third-order anisotropic term, numerical tests show that it can cause the stationary droplet to become out-of-round, which suggests the isotropic property of the LBE needs to be seriously considered in the pseudopotential LB model. By adopting the classical equilibrium moment or setting the so-called "magic" parameter to 1/12, the anisotropic term can be eliminated, which is found from the present third-order analysis and also validated numerically. As for the third-order isotropic term, when and only when it is considered, accurate continuum form pressure tensor can be definitely obtained, by which the predicted coexistence densities always agree well with the numerical results. Compared with this continuum form pressure tensor, the classical discrete form pressure tensor is accurate only when the isotropic term is a specific one. At last, in the framework of the present third-order analysis, a consistent scheme for third-order additional term is proposed, which can be used to independently adjust the coexistence densities and surface tension. Numerical tests are subsequently carried out to validate the present scheme.
Gain control of synaptic transfer from second- to third-order neurons of cockroach ocelli
1996-01-01
Synaptic transmission from second- to third-order neurons of cockroach ocelli occurs in an exponentially rising part of the overall sigmoidal characteristic curve relating pre- and postsynaptic voltage. Because of the nonlinear nature of the synapse, linear responses of second-order neurons to changes in ligh intensity are half-wave rectified, i.e., the response to a decrement in light is amplified whereas that to an increment in light is compressed. Here I report that the gain of synaptic transmission from second- to third-order neurons changes by ambient light levels and by wind stimulation applied to the cerci. Transfer characteristics of the synapse were studied by simultaneous intracellular recordings of second- and third-order neurons. Potential changes were evoked in second-order neurons by a sinusoidally modulated light with various mean luminances. With a decrease in the mean luminance (a) the mean membrane potential of second-order neurons was depolarized, (b) the synapse between the second- and third-order neurons operated in a steeper range of the exponential characteristic curve, where the gain to transmit modulatory signals was higher, and (c) the gain of third-order neurons to detect a decrement in light increased. Second-order neurons were depolarized when a wind or tactile stimulus was applied to various parts of the body including the cerci. During a wind-evoked depolarization, the synapse operated in a steeper range of the characteristic curve, which resulted in an increased gain of third-order neurons to detect light decrements. I conclude that the nonlinear nature of the synapse between the second- and third-order neurons provides an opportunity for an adjustment of gain to transmit signals of intensity change. The possibility that a similar gain control occurs in other visual systems and underlies a more advanced visual function, i.e., detection of motion, is discussed. PMID:8741734
Third-Order Memristive Morris-Lecar Model of Barnacle Muscle Fiber
NASA Astrophysics Data System (ADS)
Rajamani, Vetriveeran; Sah, Maheshwar Pd.; Mannan, Zubaer Ibna; Kim, Hyongsuk; Chua, Leon
This paper presents a detailed analysis of various oscillatory behaviors observed in relation to the calcium and potassium ions in the third-order Morris-Lecar model of giant barnacle muscle fiber. Since, both the calcium and potassium ions exhibit all of the characteristics of memristor fingerprints, we claim that the time-varying calcium and potassium ions in the third-order Morris-Lecar model are actually time-invariant calcium and potassium memristors in the third-order memristive Morris-Lecar model. We confirmed the existence of a small unstable limit cycle oscillation in both the second-order and the third-order Morris-Lecar model by numerically calculating the basin of attraction of the asymptotically stable equilibrium point associated with two subcritical Hopf bifurcation points. We also describe a comprehensive analysis of the generation of oscillations in third-order memristive Morris-Lecar model via small-signal circuit analysis and a subcritical Hopf bifurcation phenomenon.
Hong, Seung Do; Ha, Man Yeong; Balachandar, S
2009-11-01
The present study investigates the variation of static contact angle of a water droplet in equilibrium with a solid surface in the absence of a body force and the dynamic contact angles of water droplet moving on a solid surface for different characteristic energies using the molecular dynamics simulation. With increasing characteristic energy, the static contact angle in equilibrium with a solid surface in the absence of a body force decreases because the hydrophobic surface changes its characteristics to the hydrophilic surface. In order to consider the effect of moving water droplet on the dynamic contact angles, we apply the constant acceleration to an individual oxygen and hydrogen atom. In the presence of a body force, the water droplet changes its shape with larger advancing contact angle than the receding angle. The dynamic contact angles are compared with the static contact angle in order to see the effect of the presence of a body force.
Third-order terahertz response of gapped, nearly-metallic armchair graphene nanoribbons
NASA Astrophysics Data System (ADS)
Wang, Yichao; Andersen, David R.
2016-11-01
We use time dependent perturbation theory to study the terahertz nonlinear response of gapped intrinsic and extrinsic nearly-metallic armchair graphene nanoribbons of finite length under an applied electric field. Generally, the nonlinear conductances exhibit contributions due to single-photon, two-photon, and three-photon processes. The interference between each of these processes results in remarkably complex behavior for the third-order conductances, including quantum dot signatures that should be measurable with a relatively simple experimental configuration. Notably, we observe sharp resonances in the isotropic third-order response due to the Van Hove singularities in the density of states at one-, two-, and three-photon resonances. However, these resonances are absent in the anisotropic third-order response; a result of the overall symmetry of the system.
Third order effect of rotation on stellar oscillations of a β-Cephei star
NASA Astrophysics Data System (ADS)
Karami, K.
2009-01-01
Here the effect of rotation up to third order in the angular velocity of a star on the p, f and g modes is investigated. To do this, the third-order perturbation formalism presented by Soufi et al. (Astron. Astrophys. 334:911, 1998) and revised by Karami (Chin. J. Astron. Astrophys. 8:285, 2008), was used. I quantify by numerical calculations the effect of rotation on the oscillation frequencies of a uniformly rotating β-Cephei star with 12 M ⊙. For an equatorial velocity of 90 km s-1, it is found that the second- and third-order corrections for ( l, m)=(5,-4), for instance, are of order of 0.07% of the frequency for radial order n=-3 and reaches up to 0.6% for n=-20.
Solving nonlinear system of third-order boundary value problems using block method
NASA Astrophysics Data System (ADS)
See, Phang Pei; Majid, Zanariah Abdul; Suleiman, Mohamed; Ismail, Fudziah Bt; Othman, Khairil Iskandar
2015-05-01
In this paper, we propose an algorithm of two-point block method to solve the nonlinear system of third-order boundary value problems directly. The proposed method is presented in a simple form of Adams type and two approximate solutions will be obtained simultaneously with the block method using variable step size strategy. The method will be implemented with the multiple shooting technique via the three-step iterative method to generate the missing initial value. Most of the existence method will reduce the third-order boundary value problems to a system of first order equations where the systems of six equations need to be solved. The method we proposed in this paper will solve the third-order boundary value problems directly. Two numerical examples are given to illustrate the efficiency of the proposed method.
Third-order nonlinear optical properties of thin sputtered gold films
NASA Astrophysics Data System (ADS)
Xenogiannopoulou, E.; Aloukos, P.; Couris, S.; Kaminska, E.; Piotrowska, A.; Dynowska, E.
2007-07-01
Au films of thickness ranging between 5 and 52 nm were prepared by sputtering on quartz substrates and their third-order nonlinear optical response was investigated by Optical Kerr effect (OKE) and Z-scan techniques using 532 nm, 35 ps laser pulses. All prepared films were characterized by XRD, AFM and UV-VIS-NIR spectrophotometry while their third-order susceptibility χ(3) was measured and found to be of the order of 10 -9 esu. The real and imaginary parts of the third-order susceptibility were found in very good agreement with experimental results and theoretical predictions reported by Smith et al. [D.D. Smith, Y. Yoon, R.W. Boyd, Y.K. Cambell, L.A. Baker, R.M. Crooks, M. George, J. Appl. Phys. 86 (1999) 6200].
Mixed convection peristaltic flow of third order nanofluid with an induced magnetic field.
Noreen, Saima
2013-01-01
This research is concerned with the peristaltic flow of third order nanofluid in an asymmetric channel. The governing equations of third order nanofluid are modelled in wave frame of reference. Effect of induced magnetic field is considered. Long wavelength and low Reynolds number situation is tackled. Numerical solutions of the governing problem are computed and analyzed. The effects of Brownian motion and thermophoretic diffusion of nano particles are particularly emphasized. Physical quantities such as velocity, pressure rise, temperature, induced magnetic field and concentration distributions are discussed.
Ultra-high speed optical signal processing through third-order fiber nonlinearity (Invited Paper)
NASA Astrophysics Data System (ADS)
Kikuchi, Kazuro
2005-04-01
Third-order optical nonlinearity in optical fibers has many attractive applications to all-optical signal processing that will be employed in future large-capacity photonic networks. After reviewing the third-order nonlinear optical property of optical fibers, we describe our recent experimental results on all-optical signal processing functions such as wideband wavelength conversion, ultrafast gate switching, and ultrafast pulse reshaping. These functions are based on self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) in nonlinear fibers.
Mixed Convection Peristaltic Flow of Third Order Nanofluid with an Induced Magnetic Field
Noreen, Saima
2013-01-01
This research is concerned with the peristaltic flow of third order nanofluid in an asymmetric channel. The governing equations of third order nanofluid are modelled in wave frame of reference. Effect of induced magnetic field is considered. Long wavelength and low Reynolds number situation is tackled. Numerical solutions of the governing problem are computed and analyzed. The effects of Brownian motion and thermophoretic diffusion of nano particles are particularly emphasized. Physical quantities such as velocity, pressure rise, temperature, induced magnetic field and concentration distributions are discussed. PMID:24260130
Third order nonlinear optical response exhibited by mono- and few-layers of WS2
Torres-Torres, Carlos; Perea-López, Néstor; Elías, Ana Laura; ...
2016-04-13
In this work, strong third order nonlinear optical properties exhibited by WS2 layers are presented. Optical Kerr effect was identified as the dominant physical mechanism responsible for these third order optical nonlinearities. An extraordinary nonlinear refractive index together with an important contribution of a saturated absorptive response was observed to depend on the atomic layer stacking. Comparative experiments performed in mono- and few-layer samples of WS2 revealed that this material is potentially capable of modulating nonlinear optical processes by selective near resonant induced birefringence. In conclusion, we envision applications for developing all-optical bidimensional nonlinear optical devices.
A note on the nonlocal boundary value problem for a third order partial differential equation
NASA Astrophysics Data System (ADS)
Belakroum, Kheireddine; Ashyralyev, Allaberen; Guezane-Lakoud, Assia
2016-08-01
The nonlocal boundary-value problem for a third order partial differential equation d/3u (t ) d t3 +A d/u (t ) d t =f (t ), 0
An Analytical Model for the Three-Point Third-Order Velocity Correlation in Isotropic Turbulence
NASA Astrophysics Data System (ADS)
Chang, Henry; Moser, Robert
2006-11-01
In turbulent flows, the three-point third-order velocity correlation Tijk(r,r') =
Liu, Zhi-Bo; Yan, Xiao-Qing; Tian, Jian-Guo; Zhou, Wen-Yuan; Zang, Wei-Ping
2007-10-01
We present a method that combines the Z-scan technique with nonlinear ellipse rotation (NER) to measure third-order nonlinear susceptibility components. The experimental details are demonstrated, and a comprehensive theoretical analysis is given. The validity of this method is verified by the measurements of the nonlinear susceptibility tensor of a well-characterized liquid, CS2.
Rana, Anup; Lee, Sangsu; Kim, Dongho; Panda, Pradeepta K
2015-05-04
A novel electron deficient β-octakis(methylthio)porphycene, along with its Zn(ii) and Ni(ii) derivatives, was synthesized for the first time. The macrocyclic structure exhibits core ruffling with a largely red shifted absorption band (∼750 nm) and also a large enhancement in the third order nonlinear optical response.
Third-order many-body perturbation theory calculations for low-lying states in beryllium
NASA Astrophysics Data System (ADS)
Ho, Hung-Cheuk
2005-05-01
A detailed breakdown of many-body perturbation theory (MBPT) contributions through third order is presented for energies of the ten (2l ,l') states of beryllium. A total of 84 one-body and 578 two-body terms contribute to the third-order energy. Third-order MBPT calculations for monovalent atoms were carried out fifteen years ago by Blundell et al.[1] Second-order calculations for ions of the berylliumlike isoelectronic sequence were also reported six years later[2]. In that paper, only 4 one-body and 20 two-body terms contribute to the second-order energy of neutral Be. The agreement with experimental energies was at 5% level. Our study aims to present complete third-order MBPT formulas, and apply them to the simplest two-valence particles system beryllium to improve the agreement with experiment.^1 S.A. Blundell, W.R. Johnson and J. Sapirstein, Phys. Rev. A 42, 3751 (1990).^2 M.S. Safronova, W.R. Johnson and U.I. Safronova, Phys. Rev. A 53, 4036 (1996).
A Re-Averaged WENO Reconstruction and a Third Order CWENO Scheme for Hyperbolic Conservation Laws
2013-08-01
applying (L0)−1, and the time evolution of the scheme continues for the nonlinear system (56), as described above in Section 3. 6.1. Example 5, Riemann ...It is third order accurate for smooth problems. It also gives good results for non-smooth problems, including Riemann problems for the Burgers
NASA Astrophysics Data System (ADS)
Karakas, Asli; Ünver, Hüseyin
2010-05-01
( E)- N-(4-Nitrobenzylidene)-2,6-dimethylaniline ( 1) and ( E)- N-(4-nitrobenzylidene)-2,3-dimethylaniline ( 2) have been synthesized. The crystal structures of both compounds have been defined by X-ray diffraction analysis. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450 nm, showing good optical transparency to the visible light. To provide an insight into the microscopic third-order nonlinear optical (NLO) properties of the investigated molecules, both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities ( α) and second hyperpolarizabilities ( γ) at λ = 825-1125 nm and 1050-1600 nm wavelength areas have been computed using time-dependent Hartree-Fock (TDHF) method. According to the ab initio calculation results, the title molecules exhibit second hyperpolarizabilities with non-zero values, implying microscopic third-order NLO behavior.
Molecular Engineering of Supramolecular Scaffold Coatings that Can Reduce Static Platelet Adhesion
Kumar, Aryavarta M. S.; Sivakova, Sona; Fox, Justin D.; Green, Jennifer E.; Marchant, Roger E.; Rowan, Stuart J.
2008-01-01
Novel supramolecular coatings that make use of low molecular weight ditopic monomers with guanine end groups are studied using fluid tapping AFM. These molecules assemble on highly oriented pyrolytic graphite (HOPG) from aqueous solutions to form nano-sized banding structures whose sizes can be systematically tuned at the nano-scale by tailoring the molecular structure of the monomers. The nature of the self-assembly in these systems has been studied through a combination of the self-assembly of structural derivatives and molecular modeling. Furthermore, we introduce the concept of using these molecular assemblies as scaffolds to organize functional groups on the surface. As a first demonstrationof this concept, scaffold monomers that contain a monomethyl triethyleneglycol branch were used to organize these “functional” units on a HOPG surface. These supramolecular grafted assemblies have been shown to be stable in biologically-relevant environments and even have the ability to significantly reduce static platelet adhesion. PMID:18177047
Measuring the growth of matter fluctuations with third-order galaxy correlations
NASA Astrophysics Data System (ADS)
Hoffmann, K.; Bel, J.; Gaztañaga, E.; Crocce, M.; Fosalba, P.; Castander, F. J.
2015-02-01
Measurements of the linear growth factor D at different redshifts z are key to distinguish among cosmological models. One can estimate the derivative dD(z)/dln (1 + z) from redshift space measurements of the 3D anisotropic galaxy two-point correlation ξ(z), but the degeneracy of its transverse (or projected) component with galaxy bias b, i.e. ξ⊥(z) ∝ D2(z)b2(z), introduces large errors in the growth measurement. Here, we present a comparison between two methods which breaks this degeneracy by combining second- and third-order statistics. One uses the shape of the reduced three-point correlation and the other a combination of third-order one- and two-point cumulants. These methods use the fact that, for Gaussian initial conditions and scales larger than 20 h-1 Mpc, the reduced third-order matter correlations are independent of redshift (and therefore of the growth factor), while the third-order galaxy correlations depend on b. We use matter and halo catalogues from the MICE-GC simulation to test how well we can recover b(z) and therefore D(z) with these methods in 3D real space. We also present a new approach, which enables us to measure D directly from the redshift evolution of the second- and third-order galaxy correlations without the need of modelling matter correlations. For haloes with masses lower than 1014 h-1 M⊙, we find 10 per cent deviations between the different estimates of D, which are comparable to current observational errors. At higher masses, we find larger differences that can probably be attributed to the breakdown of the bias model and non-Poissonian shot noise.
NASA Astrophysics Data System (ADS)
Li, Zhong-Yu; Xu, Song; Chen, Zi-Hui; Zhang, Fu-Shi; Kasatani, Kazuo
2011-08-01
Third-order optical nonlinearities of two squarylium dyes with benzothiazole donor groups (BSQ1 and BSQ2) in chloroform solution are measured by a picosecond Z-scan technique at 532 nm. It is found that the two compounds show the saturation absorption and nonlinear self-focus refraction effect. The molecular second hyperpolarizabilities are calculated to be 7.46 × 10-31 esu and 5.01 × 10-30 esu for BSQ1 and BSQ2, respectively. The large optical nonlinearities of squarylium dyes can be attributed to their rigid and intramolecular charge transfer structure. The difference in γ values is attributed to the chloro group of benzene rings of BSQ2 and the one-photon resonance effect. It is found that the third-order nonlinear susceptibilities of two squarylium dyes are mainly determined by the real parts of χ(3), and the large optical nonlinearities of studied squarylium dyes can be attributed to the nonlinear refraction.
Mi, Yongsheng; Liang, Pengxia; Yang, Zhou; Wang, Dong; Cao, Hui; He, Wanli; Yang, Huai; Yu, Lian
2016-02-01
Recently, third-order nonlinear properties of porphyrins and porphyrin polymers and coordination compounds have been extensively studied in relation to their use in photomedicine and molecular photonics. A new functionalized porphyrin dye containing electron-rich alkynes was synthesized and further modified by formal [2+2] click reactions with click reagents tetracyanoethylene (TCNE) and 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ). The photophysical properties of these porphyrin dyes, as well as the click reaction, were studied by UV/Vis spectroscopy. In particular, third-order nonlinear optical properties of the dyes, which showed typical d-π-A structures, were characterized by Z-scan techniques. In addition, the self-assembly properties were investigated through the phase-exchange method, and highly organized morphologies were observed by scanning electron microscopy (SEM). The effects of the click post-functionalization on the properties of the porphyrins were studied, and these functionalized porphyrin dyes represent an interesting set of candidates for optoelectronic device components.
Ingram, Jani Cheri; Lehman, Richard Michael; Bauer, William Francis; O'Connell, Sean Patrick; Colwell, Frederick Scott; Shaw, Andrew D.
2003-06-01
We report the use of a surface analysis approach, static secondary ion mass spectrometry (SIMS) equipped with a molecular (ReO4-) ion primary beam, to analyze the surface of intact microbial cells. SIMS spectra of 28 microorganisms were compared to fatty acid profiles determined by gas chromatographic analysis of transesterfied fatty acids extracted from the same organisms. The results indicate that surface bombardment using the molecular primary beam cleaved the ester linkage characteristic of bacteria at the glycerophosphate backbone of the phospholipid components of the cell membrane. This cleavage enables direct detection of the fatty acid conjugate base of intact microorganisms by static SIMS. The limit of detection for this approach is approximately 107 bacterial cells/cm2. Multivariate statistical methods were applied in a graded approach to the SIMS microbial data. The results showed that the full data set could initially be statistically grouped based upon major differences in biochemical composition of the cell wall. The gram-positive bacteria were further statistically analyzed, followed by final analysis of a specific bacterial genus that was successfully grouped by species. Additionally, the use of SIMS to detect microbes on mineral surfaces is demonstrated by an analysis of Shewanella oneidensis on crushed hematite. The results of this study provide evidence for the potential of static SIMS to rapidly detect bacterial species based on ion fragments originating from cell membrane lipids directly from sample surfaces.
Prediction of static contact angles on the basis of molecular forces and adsorption data
NASA Astrophysics Data System (ADS)
Diaz, M. Elena; Savage, Michael D.; Cerro, Ramon L.
2016-08-01
At a three-phase contact line, a liquid bulk phase is in contact with and coexists with a very thin layer of adsorbed molecules. This adsorbed film in the immediate vicinity of a liquid wedge modifies the balance of forces between the liquid and solid phases such that, when included in the balance of forces, a quantitative relationship emerges between the adsorbed film thickness and the static contact angle. This relationship permits the prediction of static contact angles from molecular forces and equilibrium adsorption data by means of quantities that are physically meaningful and measurable. For n-alkanes on polytetrafluoroethylene, for which there are experimental data available on adsorption and contact angles, our computations show remarkable agreement with the data. The results obtained are an improvement on previously published calculations—particularly for alkanes with a low number of carbon atoms, for which adsorption is significant.
Finot, Eric; Fabre, Arnaud; Passian, Ali; Thundat, Thomas
2014-03-01
Mechanical resonators shaped like microcantilevers have been demonstrated as a platform for very sensitive detection of chemical and biological analytes. However, its use as an analytical tool will require fundamental understanding of the molecular absorption-induced effects in the static and dynamic sensor response. The effect of absorption-induced surface stress on the microcantilever response is here investigated using palladium hydride formation. It is shown that the resonance and deformation states of the cantilever monitored simultaneously exhibit excellent correlation with the phase of the hydride formation. However, the associated frequency shifts and quasistatic bending are observed to be independent during solid solution phase. Importantly, absorption-induced changes in the elastic parameters of the palladium film are found to play a dominant role in the static and dynamic response. The presented results help in discerning the parameters that control the cantilever response as well as the relationships between these parameters.
Prediction of static contact angles on the basis of molecular forces and adsorption data.
Diaz, M Elena; Savage, Michael D; Cerro, Ramon L
2016-08-01
At a three-phase contact line, a liquid bulk phase is in contact with and coexists with a very thin layer of adsorbed molecules. This adsorbed film in the immediate vicinity of a liquid wedge modifies the balance of forces between the liquid and solid phases such that, when included in the balance of forces, a quantitative relationship emerges between the adsorbed film thickness and the static contact angle. This relationship permits the prediction of static contact angles from molecular forces and equilibrium adsorption data by means of quantities that are physically meaningful and measurable. For n-alkanes on polytetrafluoroethylene, for which there are experimental data available on adsorption and contact angles, our computations show remarkable agreement with the data. The results obtained are an improvement on previously published calculations-particularly for alkanes with a low number of carbon atoms, for which adsorption is significant.
Second-order closure PBL model with new third-order moments: Comparison with LES data
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Minotti, F.; Ronchi, C.; Ypma, R. M.; Zeman, O.
1994-01-01
This paper contains two parts. In the first part, a new set of diagnostic equations is derived for the third-order moments for a buoyancy-driven flow, by exact inversion of the prognostic equations for the third-order moment equations in the stationary case. The third-order moments exhibit a universal structure: they all are a linear combination of the derivatives of all the second-order moments, bar-w(exp 2), bar-w theta, bar-theta(exp 2), and bar-q(exp 2). Each term of the sum contains a turbulent diffusivity D(sub t), which also exhibits a universal structure of the form D(sub t) = a nu(sub t) + b bar-w theta. Since the sign of the convective flux changes depending on stable or unstable stratification, D(sub t) varies according to the type of stratification. Here nu(sub t) approximately equal to wl (l is a mixing length and w is an rms velocity) represents the 'mechanical' part, while the 'buoyancy' part is represented by the convective flux bar-w theta. The quantities a and b are functions of the variable N(sub tau)(exp 2), where N(exp 2) = g alpha derivative of Theta with respect to z and tau is the turbulence time scale. The new expressions for the third-order moments generalize those of Zeman and Lumley, which were subsequently adopted by Sun and Ogura, Chen and Cotton, and Finger and Schmidt in their treatments of the convective boundary layer. In the second part, the new expressions for the third-order moments are used to solve the ensemble average equations describing a purely convective boundary laye r heated from below at a constant rate. The computed second- and third-order moments are then compared with the corresponding Large Eddy Simulation (LES) results, most of which are obtained by running a new LES code, and part of which are taken from published results. The ensemble average results compare favorably with the LES data.
Second-order closure PBL model with new third-order moments: Comparison with LES data
NASA Technical Reports Server (NTRS)
Canuto, V. M.; Minotti, F.; Ronchi, C.; Ypma, R. M.; Zeman, O.
1994-01-01
This paper contains two parts. In the first part, a new set of diagnostic equations is derived for the third-order moments for a buoyancy-driven flow, by exact inversion of the prognostic equations for the third-order moment equations in the stationary case. The third-order moments exhibit a universal structure: they all are a linear combination of the derivatives of all the second-order moments, bar-w(exp 2), bar-w theta, bar-theta(exp 2), and bar-q(exp 2). Each term of the sum contains a turbulent diffusivity D(sub t), which also exhibits a universal structure of the form D(sub t) = a nu(sub t) + b bar-w theta. Since the sign of the convective flux changes depending on stable or unstable stratification, D(sub t) varies according to the type of stratification. Here nu(sub t) approximately equal to wl (l is a mixing length and w is an rms velocity) represents the 'mechanical' part, while the 'buoyancy' part is represented by the convective flux bar-w theta. The quantities a and b are functions of the variable N(sub tau)(exp 2), where N(exp 2) = g alpha derivative of Theta with respect to z and tau is the turbulence time scale. The new expressions for the third-order moments generalize those of Zeman and Lumley, which were subsequently adopted by Sun and Ogura, Chen and Cotton, and Finger and Schmidt in their treatments of the convective boundary layer. In the second part, the new expressions for the third-order moments are used to solve the ensemble average equations describing a purely convective boundary laye r heated from below at a constant rate. The computed second- and third-order moments are then compared with the corresponding Large Eddy Simulation (LES) results, most of which are obtained by running a new LES code, and part of which are taken from published results. The ensemble average results compare favorably with the LES data.
NASA Astrophysics Data System (ADS)
Sudharsana, N.; Nagalakshmi, R.; Krishnakumar, V.; Sharma, A.; Fausto, R.; Row, T. N. Guru; Pal, Rumpa
2012-06-01
Single crystals of hydroxyethylammonium picrate (C8 H10N4O8; HEAP) have been grown for the first time by slow evaporation solution growth technique at room temperature, using ethanol as solvent. FT-IR and Raman spectra were recorded for HEAP at room temperature. The main vibrational bands related to NH3+ and CO- (picrate) groups, involved in charge transfer, are discussed. Second-order hyperpolarizability(γ) for the single crystal was evaluated theoretically to be 3.48×10-28 e.s.u. A Z-scan study of HEAP showed that the relative third-order nonlinear refractive index is -9.2×10-5cm2/W. The measured third-order nonlinear properties confirm the suitability of the crystal for optical limiting and switching applications.
Gillman, A.; Amadio, G.; Matouš, K.; Jackson, T. L.
2015-01-01
Obtaining an accurate higher order statistical description of heterogeneous materials and using this information to predict effective material behaviour with high fidelity has remained an outstanding problem for many years. In a recent letter, Gillman & Matouš (2014 Phys. Lett. A 378, 3070–3073. ()) accurately evaluated the three-point microstructural parameter that arises in third-order theories and predicted with high accuracy the effective thermal conductivity of highly packed material systems. Expanding this work here, we predict for the first time effective thermo-mechanical properties of granular Platonic solid packs using third-order statistical micromechanics. Systems of impenetrable and penetrable spheres are considered to verify adaptive methods for computing n-point probability functions directly from three-dimensional microstructures, and excellent agreement is shown with simulation. Moreover, a significant shape effect is discovered for the effective thermal conductivity of highly packed composites, whereas a moderate shape effect is exhibited for the elastic constants. PMID:27547103
NASA Astrophysics Data System (ADS)
Pandian, Muthu Senthil; Karuppasamy, P.; Ramasamy, P.
2017-05-01
The semi-organic nonlinear optical single crystals of potassium 3,5-dinitrobenzoate (KDNB) were grown by slow evaporation solution technique (SEST). The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. The optical transmittance, cut-off wavelength and band gap of the KDNB crystal were obtained by UV-Vis NIR spectrum analysis. Vickers microhardness analysis was carried out to identify mechanical stability and work hardening co-efficient of the grown crystal. The crystalline perfection of the grown crystal was identified by chemical etching study using water as etchant. The third-order nonlinear optical properties such as nonlinear refractive index (n2), nonlinear absorption co-efficient (β) and third order nonlinear susceptibility (χ(3)) of KDNB crystal were evaluated using Z-scan technique at the wavelength of 632.8 nm.
Axion as a cold dark matter candidate: analysis to third order perturbation for classical axion
Noh, Hyerim; Hwang, Jai-chan; Park, Chan-Gyung E-mail: jchan@knu.ac.kr
2015-12-01
We investigate aspects of axion as a coherently oscillating massive classical scalar field by analyzing third order perturbations in Einstein's gravity in the axion-comoving gauge. The axion fluid has its characteristic pressure term leading to an axion Jeans scale which is cosmologically negligible for a canonical axion mass. Our classically derived axion pressure term in Einstein's gravity is identical to the one derived in the non-relativistic quantum mechanical context in the literature. We present the general relativistic continuity and Euler equations for an axion fluid valid up to third order perturbation. Equations for axion are exactly the same as that of a zero-pressure fluid in Einstein's gravity except for an axion pressure term in the Euler equation. Our analysis includes the cosmological constant.
Mohanasubha, R; Chandrasekar, V K; Senthilvelan, M; Lakshmanan, M
2015-04-08
We unearth the interconnection between various analytical methods which are widely used in the current literature to identify integrable nonlinear dynamical systems described by third-order nonlinear ODEs. We establish an important interconnection between the extended Prelle-Singer procedure and λ-symmetries approach applicable to third-order ODEs to bring out the various linkages associated with these different techniques. By establishing this interconnection we demonstrate that given any one of the quantities as a starting point in the family consisting of Jacobi last multipliers, Darboux polynomials, Lie point symmetries, adjoint-symmetries, λ-symmetries, integrating factors and null forms one can derive the rest of the quantities in this family in a straightforward and unambiguous manner. We also illustrate our findings with three specific examples.
NASA Technical Reports Server (NTRS)
Sanghadasa, Mohan; Shin, In-Seek; Barr, Thomas A.; Clark, Ronald D.; Guo, Huai-Song; Martinez, Angela; Penn, Benjamin G.
1998-01-01
In recent years, there has been a growing interest in the development of passive optical power limiters for the protection of the human eye and solid-state sensors from damage caused by energetic light pulses and also for other switching applications. One of the key issues involved is the search for appropriate materials that show effective reverse saturable absorption. Phthalocyanines seem to be good candidates for such applications because of their higher third order nonlinearity and the unique electronic absorption characteristics. A series of 1,4,8,11,15, 18,22,25-octa-alkoxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, cobalt and nickel were characterized for their third order nonlinearity and for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers.
Observation of Third-order Nonlinearities in Graphene Oxide Film at Telecommunication Wavelengths.
Xu, Xiaochuan; Zheng, Xiaorui; He, Feng; Wang, Zheng; Subbaraman, Harish; Wang, Yaguo; Jia, Baohua; Chen, Ray T
2017-08-29
All-optical switches have been considered as a promising solution to overcome the fundamental speed limit of the current electronic switches. However, the lack of a suitable third-order nonlinear material greatly hinders the development of this technology. Here we report the observation of ultrahigh third-order nonlinearity about 0.45 cm(2)/GW in graphene oxide thin films at the telecommunication wavelength region, which is four orders of magnitude higher than that of single crystalline silicon. Besides, graphene oxide is water soluble and thus easy to process due to the existence of oxygen containing groups. These unique properties can potentially significantly advance the performance of all-optical switches.
Exact relationship for third-order structure functions in helical flows
Gomez; Politano; Pouquet
2000-05-01
An exact law for turbulent flows is written for third-order structure functions taking into account the invariance of helicity, a law akin to the so-called "4/5 law" of Kolmogorov. Here, the flow is assumed to be homogeneous, incompressible and isotropic but not invariant under reflectional symmetry. Our result is consistent with the derivation by O. Chkhetiani [JETP Lett. 10, 808, (1996)] of the von Karman-Howarth equation in the helical case, leading to a linear scaling relation for the third-order velocity correlation function. The alternative relation of the Kolmogorov type we derive here is written in terms of mixed structure functions involving combinations of differences of all components for both the velocity and vorticity fields. This relationship could prove to be a stringent test for the measuring of vorticity in the laboratory, and provide a supplementary tool for the study of the properties of helical flows.
NASA Astrophysics Data System (ADS)
Surekha, R.; Sagayaraj, P.; Ambujam, K.
2014-03-01
Optical quality bis glycine hydrobromide (BGHB) single crystal was grown by slow evaporation technique. The third order nonlinear refractive index and nonlinear absorption coefficient of the grown crystal were measured by Z-scan studies. The third order nonlinear susceptibility was found to be 9.612 × 10-4 esu which is fairly higher than the other glycine compounds. The Photoluminescence spectra reveal the emission bands for BGHB crystals. The band gap energy was calculated to be 3.1 eV. The Photoconductivity studies were employed to determine the dependence of photocurrent on the applied electric field. Negative photoconductivity was exhibited by the sample. The d.c. conductivity of the grown crystal was measured by the complex impedance analysis wherein the obtained plot in the form of semicircle finds application in Debye relaxation for materials having large dc conductivity.
Strong-continuation, contrast-invariant inpainting with a third-order optimal PDE.
Bertalmío, Marcelo
2006-07-01
PDE-based image inpainting has become a very active area of research after the pioneering works of Masnou and Morel, Bertalmío et al., and Ballester et al. In this paper, we take a different approach, inspired by the excellent work of Caselles et al. We view the inpainting problem as a particular case of image interpolation in which we intend to propagate level lines. Expressing this in terms of local neighborhoods and using a Taylor expansion we derive a third-order PDE that performs inpainting. This PDE is optimal in the sense that it is the most accurate third-order PDE which can ensure continuation of level lines. The continuation is strong, allowing the restoration of thin structures occluded by a wide gap. The result is also contrast invariant. This is a novel PDE, which, in both its accuracy and contrast invariance, outperforms the approaches cited above.
NASA Technical Reports Server (NTRS)
Sanghadasa, Mohan; Shin, In-Seek; Barr, Thomas A.; Clark, Ronald D.; Guo, Huai-Song; Martinez, Angela; Penn, Benjamin G.
1998-01-01
In recent years, there has been a growing interest in the development of passive optical power limiters for the protection of the human eye and solid-state sensors from damage caused by energetic light pulses and also for other switching applications. One of the key issues involved is the search for appropriate materials that show effective reverse saturable absorption. Phthalocyanines seem to be good candidates for such applications because of their higher third order nonlinearity and the unique electronic absorption characteristics. A series of 1,4,8,11,15, 18,22,25-octa-alkoxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, cobalt and nickel were characterized for their third order nonlinearity and for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers.
Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite
Sharma, Mamta; Tripathi, S. K. E-mail: surya-tr@yahoo.com
2015-06-24
CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n{sub 2}) and nonlinear susceptibility (χ{sup 3}) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n{sub 2} and β and is found to be of the order of 10{sup −7} – 10{sup −8} m{sup 2}/V{sup 2}. The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect.
Modal theory of slow light enhanced third-order nonlinear effects in photonic crystal waveguides.
Chen, Tao; Sun, Junqiang; Li, Linsen
2012-08-27
In this paper, we derive the couple-mode equations for third-order nonlinear effects in photonic crystal waveguides by employing the modal theory. These nonlinear interactions include self-phase modulation, cross-phase modulation and degenerate four-wave mixing. The equations similar to that in nonlinear fiber optics could be expanded and applied for third-order nonlinear processes in other periodic waveguides. Based on the equations, we systematically analyze the group-velocity dispersion, optical propagation loss, effective interaction area, slow light enhanced factor and phase mismatch for a slow light engineered silicon photonic crystal waveguide. Considering the two-photon and free-carrier absorptions, the wavelength conversion efficiencies in two low-dispersion regions are numerically simulated by utilizing finite difference method. Finally, we investigate the influence of slow light enhanced multiple four-wave-mixing process on the conversion efficiency.
Accuracy-preserving source term quadrature for third-order edge-based discretization
NASA Astrophysics Data System (ADS)
Nishikawa, Hiroaki; Liu, Yi
2017-09-01
In this paper, we derive a family of source term quadrature formulas for preserving third-order accuracy of the node-centered edge-based discretization for conservation laws with source terms on arbitrary simplex grids. A three-parameter family of source term quadrature formulas is derived, and as a subset, a one-parameter family of economical formulas is identified that does not require second derivatives of the source term. Among the economical formulas, a unique formula is then derived that does not require gradients of the source term at neighbor nodes, thus leading to a significantly smaller discretization stencil for source terms. All the formulas derived in this paper do not require a boundary closure, and therefore can be directly applied at boundary nodes. Numerical results are presented to demonstrate third-order accuracy at interior and boundary nodes for one-dimensional grids and linear triangular/tetrahedral grids over straight and curved geometries.
The determination of third order linear models from a seventh order nonlinear jet engine model
NASA Technical Reports Server (NTRS)
Lalonde, Rick J.; Hartley, Tom T.; De Abreu-Garcia, J. Alex
1989-01-01
Results are presented that demonstrate how good reduced-order models can be obtained directly by recursive parameter identification using input/output (I/O) data of high-order nonlinear systems. Three different methods of obtaining a third-order linear model from a seventh-order nonlinear turbojet engine model are compared. The first method is to obtain a linear model from the original model and then reduce the linear model by standard reduction techniques such as residualization and balancing. The second method is to identify directly a third-order linear model by recursive least-squares parameter estimation using I/O data of the original model. The third method is to obtain a reduced-order model from the original model and then linearize the reduced model. Frequency responses are used as the performance measure to evaluate the reduced models. The reduced-order models along with their Bode plots are presented for comparison purposes.
Third-order leader-following consensus with circumstance noise under impulsive and switching control
NASA Astrophysics Data System (ADS)
Sun, Mei; Han, Dun; Li, Dandan; Jia, Qiang; Wang, Yaqi
2014-02-01
This research is aimed at investigating the leader-follower problem of third-order multi-agent with noise perturbation over fixed network under impulsive and switching control. Based on stochastic differential equation theory and hybrid control theory, effective impulsive and switching controllers are proposed, and the sufficient conditions for reaching multi-agent leader-following consensus are acquired. Numerical simulations verify the validity of the theoretical research results.
Third-order coma-free point in two-mirror telescopes by a vector approach.
Ren, Baichuan; Jin, Guang; Zhong, Xing
2011-07-20
In this paper, two-mirror telescopes having the secondary mirror decentered and/or tilted are considered. Equations for third-order coma are derived by a vector approach. Coma-free condition to remove misalignment-induced coma was obtained. The coma-free point in two-mirror telescopes is found as a conclusion of our coma-free condition, which is in better agreement with the result solved by Wilson using Schiefspiegler theory.
Nonlinear Viscoelastic Analysis of Orthotropic Beams Using a General Third-Order Theory
2012-06-20
continuous functions for all the primary variables, thus simplifying the implementation . A two-point recur- rence scheme is developed such that history from...Keywords: Finite element model Spectral/hp approximations General third-order beam theory Viscoelastic behavior von Kármán nonlinearity a b s t r a c t...The fully discretized finite element equations are obtained by approximating the convolution integrals using a trapezoidal rule. A two-point recurrence
Chaotic attractors based on unstable dissipative systems via third-order differential equation
NASA Astrophysics Data System (ADS)
Campos-Cantón, E.
2016-07-01
In this paper, we present an approach how to yield 1D, 2D and 3D-grid multi-scroll chaotic systems in R3 based on unstable dissipative systems via third-order differential equation. This class of systems is constructed by a switching control law(SCL) changing the equilibrium point of an unstable dissipative system. The switching control law that governs the position of the equilibrium point varies according to the number of scrolls displayed in the attractor.
Large Enhancement of Third-Order Nonlinear Effects with a Resonant All-Dielectric Metasurface
2016-09-12
Large Enhancement of Third-Order Nonlinear Effects with a Resonant All -Dielectric Metasurface Samad Jafar-Zanjani,1, a) Jierong Cheng,1 Vladimir...September 2016) A novel low-profile nonlinear metasurface, consisting of a single-layer of all -dielectric material, is proposed and numerically investigated...with an unpatterend film. The proposed all -dielectric metasurface in this work is ultrathin and easy to fabricate. We envision a number of applications
Organometallic Compounds and Polymers with Second and Third Order Nonlinear Optical Properties
1993-05-06
Nonlinear Optical Properties of Inorganic Coordination Polymers . William Chiang, Mark E. Thompson, Donna Van Engen , "Organic Materials for Nonlinear...Organometallic Compounds and Polymers with Second and Third Order Nonlinear Optical Pro. -c.AUTHOR(S) 61102F 2303 All Mark E. Thompson, PI 7. PERFORMING...scale Sc -Cr $5 Fe > Co. Polar coordination polymers were prepared in which excellent polar order was found in the polyermic chains. however, the
Third-order nonlinear properties of [PbPc (CP) 4] at 600nm wavelength
NASA Astrophysics Data System (ADS)
Zhang, Xiumei; Shui, Min; Li, Changwei; Song, Yinglin
2009-07-01
Several heavy mental substituted phthalocyanines are effective materials for optical limiters in the visible and near IR. Lead-tetrakis (cumplphenoxy) phthalocyanine [PbPc (CP)4] was identified as especially attractive for optical limiting applications. In the paper, we investigate the third-order optical nonlinearities of [PbPc (CP) 4] at 600nm by a nonlinear-imaging technique with a phase object (NIT-PO). The theoretical simulation fit well with experimental results.
Non-local bias contribution to third-order galaxy correlations
NASA Astrophysics Data System (ADS)
Bel, J.; Hoffmann, K.; Gaztañaga, E.
2015-10-01
We study halo clustering bias with second- and third-order statistics of halo and matter density fields in the Marenostrum Institut de Ciències de l'Espai (MICE) Grand Challenge simulation. We verify that two-point correlations deliver reliable estimates of the linear bias parameters at large scales, while estimations from the variance can be significantly affected by non-linear and possibly non-local contributions to the bias function. Combining three-point auto- and cross-correlations we find, for the first time in configuration space, evidence for the presence of such non-local contributions. These contributions are consistent with predicted second-order non-local effects on the bias functions originating from the dark matter tidal field. Samples of massive haloes show indications of bias (local or non-local) beyond second order. Ignoring non-local bias causes 20-30 and 5-10 per cent overestimation of the linear bias from three-point auto- and cross-correlations, respectively. We study two third-order bias estimators that are not affected by second-order non-local contributions. One is a combination of three-point auto- and cross-correlations. The other is a combination of third-order one- and two-point cumulants. Both methods deliver accurate estimations of the linear bias. Ignoring non-local bias causes higher values of the second-order bias from three-point correlations. Our results demonstrate that third-order statistics can be employed for breaking the growth-bias degeneracy.
Scale and modify for the second and third order BDF methods
NASA Astrophysics Data System (ADS)
Heard, Allison
2010-03-01
This paper investigates a ‘scale and modify' technique used with variable stepsize BDF methods. When the stepsize is changed using the usual scaling procedure for Nordsieck methods, there can be adverse affects on the stability unless a severe restriction is placed on the allowable stepsize ratios. However, a modification to this scaling procedure may extend the range of permissible stepsize ratios. Results for the Nordsieck form of the second and third order methods indicate that this may be possible.
Third-order aberration analysis of an off-axial optical system
NASA Astrophysics Data System (ADS)
Wakazono, Tsuyoshi; Yatagai, Toyohiko; Araki, Keisuke
2016-02-01
The aberration theory applied to co-axial optical systems is extended to off-axial systems, for which third-order aberration coefficients are considered. The derived aberrations are analyzed using three-dimensional ray bundles, spot diagrams, and image charts, and classified in relation to the system symmetry. This theory is very useful for optical designers, allowing them to clarify the relationship between the structures of off-axial optical systems and the corresponding off-axial aberrations.
NASA Astrophysics Data System (ADS)
Gariel, J.; Marcilhacy, G.; Santos, N. O.
2008-02-01
We extend the method of separation of variables, studied by Léauté and Marcilhacy [Ann. Inst. Henri Poincare, Sect. A 331, 363 (1979)], to obtain transcendent solutions of the field equations for stationary axisymmetric systems. These solutions depend on transcendent functions satisfying a third order differential equation. For some solutions this equation satisfies the necessary conditions, but not sufficient, to have fixed critical points.
1981-05-01
between atoms. iw 2 Several physical properties of solids result from, or depend upon, the presence of the anharmonic terms in the strain energy density...experimental techniques have been used to measure third-order elastic constants of various solids . Measurement of the dependence of the second-order...constants are measured by an ultrasonic harmonic generation technique, As an initially sinusoidal wave propagates through a solid , higher harmonics are
Third-order integrable difference equations generated by a pair of second-order equations
NASA Astrophysics Data System (ADS)
Matsukidaira, Junta; Takahashi, Daisuke
2006-02-01
We show that the third-order difference equations proposed by Hirota, Kimura and Yahagi are generated by a pair of second-order difference equations. In some cases, the pair of the second-order equations are equivalent to the Quispel-Robert-Thomson (QRT) system, but in the other cases, they are irrelevant to the QRT system. We also discuss an ultradiscretization of the equations.
Investigation of a Third Order Baro-Damped Vertical Channel of INS.
1982-12-01
vertical channel for a vehicle carrying out a TERCOM -update in light of disturbance and noise inputs. This project was sponsored by the Navigation Branch of...induced altitude error and a disturbance of known magnitude. For a vehicle carrying out a TERCOM -update immediately following a vertical descent, and being...performance improvement over the classical gains for a vehicle carrying out the TERCOM -update. viii INVESTIGATION OF A THIRD-ORDER BARO-DAMPED VERTICAL
NASA Astrophysics Data System (ADS)
Endres, F.; Steinmann, P.
2014-12-01
Molecular dynamics (MD) simulations of ferroelectric materials have improved tremendously over the last few decades. Specifically, the core-shell model has been commonly used for the simulation of ferroelectric materials such as barium titanate. However, due to the computational costs of MD, the calculation of ferroelectric hysteresis behaviour, and especially the stress-strain relation, has been a computationally intense task. In this work a molecular statics algorithm, similar to a finite element method for nonlinear trusses, has been implemented. From this, an algorithm to calculate the stress dependent continuum deformation of a discrete particle system, such as a ferroelectric crystal, has been devised. Molecular statics algorithms for the atomistic simulation of ferroelectric materials have been previously described. However, in contrast to the prior literature the algorithm proposed in this work is also capable of effectively computing the macroscopic ferroelectric butterfly hysteresis behaviour. Therefore the advocated algorithm is able to calculate the piezoelectric effect as well as the converse piezoelectric effect simultaneously on atomistic and continuum length scales. Barium titanate has been simulated using the core-shell model to validate the developed algorithm.
Tsutsui, Yushi; Hayakawa, Tomokatsu; Kawamura, Go; Nogami, Masayuki
2011-07-08
In order to elucidate the relationship for third-order nonlinear optical properties of anisotropic metal nanoparticles between the incident laser wavelength and surface plasmon resonance (SPR) wavelength, gold nanorods (GNRs) with a tuned longitudinal SPR mode in frequency were prepared by seed-mediated methods with two different surfactants, cetyltrimethylammonium bromide (CTAB) and benzyldimethylammonium chloride (BDAC). The real and imaginary parts of the third-order nonlinear optical susceptibilities χ(3) were examined by near-infrared (800 nm) femtosecond Z-scan and I-scan techniques for various gold sols with SPR wavelengths of 530 nm (spheres), 800 nm (nanorods) and 1000 nm (nanorods), named as 530GNSs, 800GNRs and 1000GNRs, respectively. All the samples showed intrinsically third-order nonlinear optical refractive responses. However, as for the real part of χ(3) for one particle, 800GNRs whose plasmon peak was tuned to the incident laser wavelength exhibited a Reχ(3) value 45 times stronger than 530GNSs. More interestingly, the imaginary part of χ(3) was more greatly influenced at the tuned SPR wavelength. Here we first demonstrate that 800GNRs showed plasmon-enhanced saturable absorption (SA) due to a longitudinal SPR tuned to the incident laser wavelength.
NASA Astrophysics Data System (ADS)
Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing
2016-06-01
The symplectic integration method is popular in high-accuracy numerical simulations when discretizing temporal derivatives; however, it still suffers from time-dispersion error when the temporal interval is coarse, especially for long-term simulations and large-scale models. We employ the inverse time dispersion transform (ITDT) to the third-order symplectic integration method to reduce the time-dispersion error. First, we adopt the pseudospectral algorithm for the spatial discretization and the third-order symplectic integration method for the temporal discretization. Then, we apply the ITDT to eliminate time-dispersion error from the synthetic data. As a post-processing method, the ITDT can be easily cascaded in traditional numerical simulations. We implement the ITDT in one typical exiting third-order symplectic scheme and compare its performances with the performances of the conventional second-order scheme and the rapid expansion method. Theoretical analyses and numerical experiments show that the ITDT can significantly reduce the time-dispersion error, especially for long travel times. The implementation of the ITDT requires some additional computations on correcting the time-dispersion error, but it allows us to use the maximum temporal interval under stability conditions; thus, its final computational efficiency would be higher than that of the traditional symplectic integration method for long-term simulations. With the aid of the ITDT, we can obtain much more accurate simulation results but with a lower computational cost.
Critical damping conditions for third order muscle models: implications for force control.
Piovesan, Davide; Pierobon, Alberto; Mussa Ivaldi, Ferdinando A
2013-10-01
Experimental results presented in the literature suggest that humans use a position control strategy to indirectly control force rather than direct force control. Modeling the muscle-tendon system as a third-order linear model, we provide an explanation of why an indirect force control strategy is preferred. We analyzed a third-order muscle system and verified that it is required for a faithful representation of muscle-tendon mechanics, especially when investigating critical damping conditions. We provided numerical examples using biomechanical properties of muscles and tendons reported in the literature. We demonstrated that at maximum isotonic contraction, for muscle and tendon stiffness within physiologically compatible ranges, a third-order muscle-tendon system can be under-damped. Over-damping occurs for values of the damping coefficient included within a finite interval defined by two separate critical limits (such interval is a semi-infinite region in second-order models). An increase in damping beyond the larger critical value would lead the system to mechanical instability. We proved the existence of a theoretical threshold for the ratio between tendon and muscle stiffness above which critical damping can never be achieved; thus resulting in an oscillatory free response of the system, independently of the value of the damping. Under such condition, combined with high muscle activation, oscillation of the system can be compensated only by active control.
Ab initio Molecular Dynamics Simulations of Water Under Static and Shock Compressed Conditions
Goldman, N; Fried, L E; Mundy, C J; Kuo, I W; Curioni, A; Reed, E
2007-07-25
We report herein a series of ab initio simulations of water under both static and shocked conditions. We have calculated the coherent x-ray scattering intensity of several phases of water under high pressure, using ab initio Density Functional Theory (DFT). We provide new atomic scattering form factors for water at extreme conditions, which take into account frequently neglected changes in ionic charge and electron delocalization. We have also simulated liquid water undergoing shock loading of velocities from 5-11 km/s using the Multi-Scale Shock Technique (MSST). We show that Density Functional Theory (DFT) molecular dynamics results compare extremely well to experiments on the water shock Hugoniot.
Taghizadeh, Ata; Favis, Basil D
2013-02-15
Starch gelatinization in the presence of high molecular weight polyol plasticizers and water was studied under static and dynamic conditions and was compared to a glycerol reference. For static gelatinization, glycerol, sorbitol, diglycerol and polyglycerol were examined using polarized light microscopy and differential scanning calorimetry. A wide range of starch/water/plasticizer compositions were prepared to explore the gelatinization regime for each plasticizer. The plasticizers show that the onset and conclusion temperatures for sorbitol and glycerol are in the same range and are lower than the other two plasticizers. On the other hand, polyglycerol shows a higher gelatinization temperature than diglycerol because of its higher molecular weight and viscosity. The results indicate that in the case of all plasticizers, increasing the water content tends to decrease the gelatinization temperature and, except for polyglycerol, increasing the plasticizer content increases the gelatinization temperature. In the case of polyglycerol, however, increasing the plasticizer content had the opposite effect and this was found to be related to the borderline solubility of polyglycerol in water. When the polyglycerol/water solubility was increased by increasing the temperature of the water/plasticizer/starch slurry, the gelatinization temperature dependence was found to be similar to the other polyols. A rheological technique was developed to study the dynamic gelatinization process by tracking the influence of shear on the complex viscosity in a couette flow system. Glycerol, diglycerol and sorbitol were subjected to different dynamic gelatinization treatments and the results were compared with static gelatinization. It is quantitatively shown that shear has a major effect on the gelatinization process. The conclusion temperature of gelatinization is significantly diminished (up to 21 °C) in the presence of shear whereas the onset temperature of gelatinization remains
Static and animated molecular views of a tumorigenic chemical bound to DNA
Broyde, S.; Xu, Rong ); Hingerty, B.E. ); O'Handley, S.F.; Krugh, T.R. . Dept. of Chemistry)
1991-01-01
Static and dynamic molecular views of a short segment of DNA modified by the tumorigenic aromatic amine 2-acetylaminofluorene (AAF) have been realized by a combination of high resolution nuclear magnetic resonance (NMR) studies in solution and molecular mechanics and molecular dynamics simulations carried out on supercomputers. Thus, the effect of AAF on the structure of the Watson-Crick B-DNA double helix has been elucidated, after two decades of intense interest, via a powerful synergy between state-of-the-art supercomputing NMR investigations. The AAF is situated in the minor groove of a B-DNA double helix which flexes and bends, and the carcinogen moves between positions where it is stacked with adjacent DNA base and positions where it protrudes further into the groove. The AAF modified DNA base, guanine, is displaced from its normal situation paired with partner cytosine. Also, a base pair adjacent to the modification becomes more mobile. These molecular views offer some possible insight on the early molecular events that may implicate AAF in tumor initiation. 16 refs., 3 figs.
NASA Astrophysics Data System (ADS)
Toonen, Ryan; Will Cole, Melanie; Ivill, Mathew; Hirsch, S.; Integrated Electromagnetic Materials Team Team
2013-03-01
Using microwave reflection spectroscopy, the complex permittivities of etch-defined, 240 nm thick, [Ba(0.6)Sr(0.4)]TiO(3), thin films were measured over the frequency range of (1 to 4) GHz. The observed electro-acoustic resonances were characterized as a function of extrinsic electric field magnitude, ambient temperature, and sample diameter. The real and imaginary parts of the measured permittivities were fit to frequency-dependent functions derived from the Lorentz oscillator model. From these functions, extracted static dielectric constants were found to display excellent agreement with a closed-form expression derived by calculating third-order nonlinear susceptibility from the Landau-Devonshire-Ginzberg model [R. C. Toonen and M. W. Cole, Appl. Phys. Lett. 100, 222908 (2012)]. By investigating the behavior of these loss mechanisms in response to external stimuli, we have gained insight with respect to how such effects can be reduced or even eliminated. It is also possible that these loss mechanisms could be exploited for the purpose of engineering micro-/nano-electro-mechanical resonators and super-compact high-quality-factor frequency-selective filters. Funding for these efforts was provided by an award from the ARL Director's Research Initiative (FY10-WMR-27).
NASA Astrophysics Data System (ADS)
Ganguly, Jayanta; Saha, Surajit; Pal, Suvajit; Ghosh, Manas
2016-03-01
We perform a meticulous analysis of profiles of third-order nonlinear optical susceptibility (TONOS) of impurity doped quantum dots (QDs) in the presence and absence of noise. We have invoked Gaussian white noise in the present study and noise has been introduced to the system additively and multiplicatively. The QD is doped with a Gaussian impurity. A magnetic field applied perpendicularly serves as a confinement source and the doped system has been exposed to a static external electric field. The TONOS profiles have been monitored against a continuous variation of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, Al concentration, dopant potential, relaxation time, anisotropy, and noise strength assume different values. Moreover, the influence of mode of introduction of noise (additive/multiplicative) on the TONOS profiles has also been addressed. The said profiles are found to be consisting of interesting observations such as shift of TONOS peak position and maximization/minimization of TONOS peak intensity. The presence of noise alters the features of TONOS profiles and sometimes enhances the TONOS peak intensity from that of noise-free state. Furthermore, the mode of application of noise also often tailors the TONOS profiles in diverse fashions. The observations accentuate the possibility of tuning the TONOS of doped QD systems in the presence of noise.
Atchison, D A; Smith, G
1998-11-01
To investigate the feasibility of using gradient index media in contact lenses, we developed simple methods which we used to derive the power and aberrations associated with the contact lenses. In one method, we assume that the height of a ray does not change as it passes through the lens. We describe a second method in which the ray is assumed to follow a parabolic path as it passes through the lens. We use sophisticated third-order theory and finite raytracing for comparison with these methods. The methods are compared for contact lenses with parabolic radial gradient index media. Without the gradient index, these lenses would have zero power. The formula for power which assumes no change in ray height gives errors of approximally 0.8 and 1.5% for lenses of thicknesses 0.18 and 0.36 mm. However, the formula for third-order spherical aberration which uses the same assumption gives poor estimations. The method for calculating power using the parabolic ray path is very accurate. The sophisticated third-order aberration theory was reasonably accurate out to 2.5 mm ray height. The contact lenses with the gradient index media have much smaller aberration in air than do conventional contact lenses of the same powers, with the sign of the aberration being reversed. Our simple procedures give good estimations of powers of contact lenses with gradient index media. The approximate method, which assumes that the height of a ray does not change as it passes through the lens, should not be used for finding the spherical aberration of such a lens. Contact lenses with gradient index media have potential for minimizing spherical aberration.
Beyond pairs: definition and interpretation of third-order structure in spatial point patterns.
Kaito, Chiho; Dieckmann, Ulf; Sasaki, Akira; Takasu, Fugo
2015-05-07
Spatial distributions of biological species are an important source of information for understanding local interactions at the scale of individuals. Technological advances have made it easier to measure these distributions as spatial point patterns, specifying the locations of individuals. Extensive attention has been devoted to analyzing the second-order structure of such point patterns by focusing on pairs of individuals, and it is well known that the local crowdedness of individuals can thus be quantified. Statistical measures such as a point pattern׳s pair correlation function or Ripley׳s K function show whether a given point pattern is clustered (excess of short-distance pairs) or overdispersed (shortage of short-distance pairs). These notions are naturally defined in comparison with control patterns exhibiting complete spatial randomness, i.e., an absence of any spatial structure. However, there is no rational reason why the analysis of point patterns should stop at the second order. In this paper, we focus on triplets of individuals in an attempt to quantify and interpret the third-order structure of a point pattern. We demonstrate that point patterns with "bandedness", in which individuals are primarily distributed within bands, can be detected by an excess of thinner triplets at a characteristic spatial scale linked to the band׳s width. In this context, we show how the generation of control patterns as a reference for gauging a test pattern׳s triplet frequencies is critical for defining and interpreting the third-order structure of point patterns. Since perfect information on a point pattern׳s second-order structure typically suffices for its unique reconstruction (up to translation, rotation, and reflection), we conjecture that it is essential to minimally coarse-grain such second-order information before using it to generate control patterns for identifying a point pattern׳s third-order structure. We recommend the further exploration of this
Quantum theory of the third-order nonlinear electrodynamic effects of graphene
NASA Astrophysics Data System (ADS)
Mikhailov, S. A.
2016-02-01
The linear energy dispersion of graphene electrons leads to a strongly nonlinear electromagnetic response of this material. We develop a general quantum theory of the third-order nonlinear local dynamic conductivity of graphene σα β γ δ(ω1,ω2,ω3) , which describes its nonlinear response to a uniform electromagnetic field. The derived analytical formulas describe a large number of different nonlinear phenomena such as the third-harmonic generation, the four-wave mixing, the saturable absorption, the second-harmonic generation stimulated by a dc electric current, etc., which may be used in different terahertz and optoelectronic devices.
X-ray plane-wave diffraction effects in a crystal with third-order nonlinearity
NASA Astrophysics Data System (ADS)
Balyan, M. K.
2016-12-01
The two-wave dynamical diffraction in the Laue geometry has been theoretically considered for a plane X-ray wave in a crystal with a third-order nonlinear response to the external field. An analytical solution to the problem stated is found for certain diffraction conditions. A nonlinear pendulum effect is analyzed. The nonlinear extinction length is found to depend on the incident-wave intensity. A pendulum effect of a new type is revealed: the intensities of the transmitted and diffracted waves periodically depend on the incidentwave intensity at a fixed crystal thickness. The rocking curves and Borrmann nonlinear effect are numerically calculated.
Third-order aberrations of a prism with spherically curved surfaces.
Morrissey, P F
1994-05-01
A third-order analysis of a spherically curved prism in a converging beam shows that solutions exist that permit the beam to pass without aberration. A reflecting telescope with such a prism in front of the focus would form a high-throughput astronomical spectrometer for stellar sources. This configuration would yield diffraction-limited performance at a single wavelength. A LiF prism has been designed for a rocket telescope that will image Jupiter from 1216 to 1608 Å with a spatial resolution limited by the 0.5-arcsec pixels of the detector.
Third order nonlinearity in pulsed laser deposited LiNbO{sub 3} thin films
Tumuluri, Anil; Rapolu, Mounika; Rao, S. Venugopal E-mail: svrsp@uohyd.ernet.in; Raju, K. C. James E-mail: svrsp@uohyd.ernet.in
2016-05-06
Lithium niobate (LiNbO{sub 3}) thin films were prepared using pulsed laser deposition technique. Structural properties of the same were examined from XRD and optical band gap of the thin films were measured from transmittance spectra recorded using UV-Visible spectrophotometer. Nonlinear optical properties of the thin films were recorded using Z-Scan technique. The films were exhibiting third order nonlinearity and their corresponding two photon absorption, nonlinear refractive index, real and imaginary part of nonlinear susceptibility were calculated from open aperture and closed aperture transmission curves. From these studies, it suggests that these films have potential applications in nonlinear optical devices.
Dynamical Tangles in Third-Order Oscillator with Single Jump Function
Petržela, Jiří
2014-01-01
This contribution brings a deep and detailed study of the dynamical behavior associated with nonlinear oscillator described by a single third-order differential equation with scalar jump nonlinearity. The relative primitive geometry of the vector field allows making an exhaustive numerical analysis of its possible solutions, visualizations of the invariant manifolds, and basins of attraction as well as proving the existence of chaotic motion by using the concept of both Shilnikov theorems. The aim of this paper is also to complete, carry out and link the previous works on simple Newtonian dynamics, and answer the question how individual types of the phenomenon evolve with time via understandable notes. PMID:25544951
Third-order elastic constants of diamond determined from experimental data
Winey, J. M.; Hmiel, A.; Gupta, Y. M.
2016-06-01
The pressure derivatives of the second-order elastic constants (SOECs) of diamond were determined by analyzing previous sound velocity measurements under hydrostatic stress [McSkimin and Andreatch, J. Appl. Phys. 43, 294 (1972)]. Furthermore, our analysis corrects an error in the previously reported results.We present a complete and corrected set of third-order elastic constants (TOECs) using the corrected pressure derivatives, together with published data for the nonlinear elastic response of shock compressed diamond [Lang and Gupta, Phys. Rev. Lett. 106, 125502 (2011)] and it differs significantly from TOECs published previously.
NASA Astrophysics Data System (ADS)
Zhan, Xiaowei; Liu, Yunqi; Zhu, Daoben; Liu, Xuchun; Xu, Gang; Ye, Peixian
2002-08-01
Off-resonant third-order nonlinear optical properties using degenerate four-wave mixing measurements in solution at 1064 nm have been studied for novel π-conjugated, processible, optically transparent and thermally stable copolymers constituted of carbazole and fluorene. The second-order hyperpolarizability γ1111 per repeat unit of the polymer containing alkyne segment (Cz-PFE) is as high as 6.5×10 -31 esu. The large nonlinearity of Cz-PFE is attributed to its rigid planar and intrachain charge transfer structure.
Spectral methods for some singularly perturbed third order ordinary differential equations
NASA Astrophysics Data System (ADS)
Temsah, R.
2008-01-01
Spectral methods with interface point are presented to deal with some singularly perturbed third order boundary value problems of reaction-diffusion and convection-diffusion types. First, linear equations are considered and then non-linear equations. To solve non-linear equations, Newton?s method of quasi-linearization is applied. The problem is reduced to two systems of ordinary differential equations. And, then, each system is solved using spectral collocation methods. Our numerical experiments show that the proposed methods are produce highly accurate solutions in little computer time when compared with the other methods available in the literature.
NASA Astrophysics Data System (ADS)
Sudheesh, P.; Rao, D. Mallikharjuna; Chandrasekharan, K.
2014-01-01
The third-order nonlinear optical properties of newly synthesized phenylhydrazone derivatives and the influence of noble metal nanoparticles (Ag & Au) on their nonlinear optical responses were investigated by employing Degenerate Four wave Mixing (DFWM) technique with a 7 nanosecond, 10Hz Nd: YAG laser pulses at 532nm. Metal nanoparticles were prepared by laser ablation and the particle formation was confirmed using UV-Visible spectroscopy, Transmission Electron Microscopy (TEM). The nonlinear optical susceptibility were measured and found to be of the order 10-13esu. The results are encouraging and conclude that the materials are promising candidate for future optical device applications.
Two-mirror telescope design with third-order coma insensitive to decenter misalignment.
Scaduto, Lucimara Cristina Nakata; Sasian, Jose; Stefani, Mario Antonio; Neto, Jarbas Caiado de Castro
2013-03-25
Misalignments always occur in real optical systems. These misalignments do not generate new aberration forms, but they change the aberration field dependence. Two-mirror telescopes have been used in several applications. We analyze a two-mirror telescope configuration that has negligible sensitivity to decenter misalignments. By applying the wave aberration theory for plane-symmetric optical systems it is shown that the asphericity in the secondary mirror, if properly chosen, can compensate for any decenter perturbation allowing third-order coma unchanged across the field of view. For any two-mirror system it is possible to find a configuration in which decenter misalignments do not generate field-uniform coma.
Third-order nonlinearities and optical limiting properties of complex Co 2L 3
NASA Astrophysics Data System (ADS)
Guo, Sheng-Li; Li, Tie-Pan; Wang, Tie-Bang; Liu, Zhao-Sen; Cao, Tian-De
2007-01-01
With nanosecond pulses at a wavelength of 532 nm, we investigated the third-order optical nonlinearities of a dinuclear Co(II) triple-helical complex Co 2L 3 {L = bis[4-(2-pyridyl-methyleneamino) phenyl] methane} by a Z-scan technique. The optical limiting properties are measured by a transmission technique. The experimental data are theoretically fitted; the mechanism for the optical nonlinearities and the optical limiting properties is discussed. The absorption cross-sections of the ground state and the excited states are evaluated by a rate equation model.
Computation of turbulent pipe and duct flow using third order upwind scheme
NASA Technical Reports Server (NTRS)
Kawamura, T.
1986-01-01
The fully developed turbulence in a circular pipe and in a square duct is simulated directly without using turbulence models in the Navier-Stokes equations. The utilized method employs a third-order upwind scheme for the approximation to the nonlinear term and the second-order Adams-Bashforth method for the time derivative in the Navier-Stokes equation. The computational results appear to capture the large-scale turbulent structures at least qualitatively. The significance of the artificial viscosity inherent in the present scheme is discussed.
X-ray third-order nonlinear dynamical diffraction in a crystal
Balyan, M. K.
2015-12-15
The dynamic diffraction of an X-ray wave in a crystal with a third-order nonlinear response to external field strength has been theoretically investigated. General equations for the wave propagation in crystal and nonlinear Takagi equations for both ideal and deformed crystals are derived. Integrals of motion are determined for the nonlinear problem of dynamic diffraction. The results of the numerical calculations of reflectivity in the symmetric Laue geometry for an incident plane wave and the intensity distributions on the output crystal surface for a point source are reported as an example.
Sudheesh, P.; Chandrasekharan, K.; Rao, D. Mallikharjuna
2014-01-28
The third-order nonlinear optical properties of newly synthesized phenylhydrazone derivatives and the influence of noble metal nanoparticles (Ag and Au) on their nonlinear optical responses were investigated by employing Degenerate Four wave Mixing (DFWM) technique with a 7 nanosecond, 10Hz Nd: YAG laser pulses at 532nm. Metal nanoparticles were prepared by laser ablation and the particle formation was confirmed using UV-Visible spectroscopy, Transmission Electron Microscopy (TEM). The nonlinear optical susceptibility were measured and found to be of the order 10{sup −13}esu. The results are encouraging and conclude that the materials are promising candidate for future optical device applications.
Enhanced dynamical response of derivative controlled third order phase locked loops
NASA Astrophysics Data System (ADS)
Chakraborty, S.; Sarkar, B. C.
2016-07-01
Dynamical responses of third order phase locked loops with resonant filters are examined by modifying the control signal applied to loop oscillator. Using signals obtained at some internal nodes of loop resonant filter, the control signal is modified. These signals are effectively single or double derivatives of normal control signal. Performances of modified loops are found to improve during transient and tracking modes of loop operation. This is established through analytical, numerical simulation and experimental studies. The dynamics of the loops in unstable self-oscillatory and aperiodic oscillating modes could also be controlled by these additional derivative control signals.
On scaling properties of crossing the third-order resonance in particle accelerator
Lee, S.Y.; Pang, X.; Jing, Y.; Luo, T.; Ng, K.Y.; /Fermilab
2011-12-01
We study effects of charged particle beams crossing a third-order resonance in an accelerator. The distortion of invariant torus during the resonance crossing is used to set 20% emittance growth or 2.5% of trap fraction as the critical resonance strength. We find a simple scaling law for the critical resonance strength vs the tune ramp rate and the initial emittance. The scaling law can be derived by solving Hamilton's equation of motion with stationary phase condition. Such scaling law can be used to evaluate the performance in high power accelerators, such as the FFAG and cyclotron.
First integrals and parametric solutions of third-order ODEs admitting {\\mathfrak{sl}(2, {R})}
NASA Astrophysics Data System (ADS)
Ruiz, A.; Muriel, C.
2017-05-01
A complete set of first integrals for any third-order ordinary differential equation admitting a Lie symmetry algebra isomorphic to sl(2, {R}) is explicitly computed. These first integrals are derived from two linearly independent solutions of a linear second-order ODE, without additional integration. The general solution in parametric form can be obtained by using the computed first integrals. The study includes a parallel analysis of the four inequivalent realizations of sl(2, {R}) , and it is applied to several particular examples. These include the generalized Chazy equation, as well as an example of an equation which admits the most complicated of the four inequivalent realizations.
Triska, F.J.; Kennedy, V.C.; Avanzino, R.J.; Zellweger, G.W.; Bencala, K.E.
1989-01-01
Chloride and nitrate were coinjected into the surface waters of a third-order stream for 20 d to exmaine solute retention, and the fate of nitrate during subsurface transport. A series of wells (shallow pits) 0.5-10 m from the adjacent channel were sampled to estimate the lateral interflow of water. Two subsurface return flows beneath the wetted channel were also examined. Results indicated that the capacity of the hyporheic zone for transient solute storage and as potential biological habitat varies with channel morphology, bed roughness, and permeability. A conceptual model that considers the groundwater-stream water interface as the fluvial boundary is proposed. -from Authors
Wu, Zhenqin; Bi, Huimin; Pan, Sichen; Meng, Lingyi; Zhao, Xin Sheng
2016-11-17
Fluorescence correlation spectroscopy (FCS) is a powerful tool to investigate molecular diffusion and relaxations, which may be utilized to study many problems such as molecular size and aggregation, chemical reaction, molecular transportation and motion, and various kinds of physical and chemical relaxations. This article focuses on a problem related to using the relaxation term to study a reaction. If two species with different fluorescence photon emission efficiencies are connected by a reaction, the kinetic and equilibrium properties will be manifested in the relaxation term of the FCS curve. However, the conventional FCS alone cannot simultaneously determine the equilibrium constant (K) and the relative fluorescence brightness (Q), both of which are indispensable in the extraction of thermodynamic and kinetic information from the experimental data. To circumvent the problem, an assumption of Q = 0 is often made for the weak fluorescent species, which may lead to numerous errors when the actual situation is not the case. We propose to combine the third-order FCS with the conventional second-order FCS to determine K and Q without invoking other resources. The strategy and formalism are verified by computer simulations and demonstrated in a classical example of the hairpin DNA-folding process.
Extraction of depth profiles of third-order elastic constants in cracked media
NASA Astrophysics Data System (ADS)
Rjelka, Marek; Koehler, Bernd; Mayer, Andreas
2017-02-01
Elastic constants of components are usually determined by tensile tests in combination with ultrasonic experiments. However, these properties may change due to e.g. mechanical treatments or service conditions during their lifetime. Knowledge of the actual material parameters is key to the determination of quantities like residual stresses present in the medium. In this work the acoustic nonlinearity parameter (ANP) for surface acoustic waves is examined through the derivation of an evolution equation for the amplitude of the second harmonic. Given a certain depth profile of the third-order elastic constants, the dependence of the ANP with respect to the input frequency is determined and on the basis of these results, an appropriate inversion method is developed. This method is intended for the extraction of the depth dependence of the third-order elastic constants of the material from second-harmonic generation and guided wave mixing experiments, assuming that the change in the linear Rayleigh wave velocity is small. The latter assumption is supported by a 3D-FEM model study of a medium with randomly distributed micro-cracks as well as theoretical works on this topic in the literature.
Dhanalakshmi, B.; Ponnusamy, S.; Muthamizhchelvan, C.; Subhashini, V.
2015-10-15
Highlights: • EDA4NPH crystal possesses negative nonlinear refractive index. • The crystal exhibits high third-order NLO susceptibility. • Wide transparency of the crystal makes it suitable for NLO applications. • Dielectric studies substantiate the suitability for electro-optic applications. • The crystal possesses suitable mechanical strength for device fabrication. - Abstract: Bulk crystals of the charge-transfer complex, ethylenediamine-4-nitrophenolate monohydrate, were grown by slow solvent evaporation method from aqueous solution at room temperature. The X-ray diffraction measurements showed that the crystal belongs to centrosymmetric space group C2/c of monoclinic system. The functional groups in the complex were identified using FTIR, FTRaman and FTNMR analyses. The Z-scan measurements revealed the negative nonlinear refractive index of the crystal. The nonlinear absorption coefficient and third order nonlinear optical susceptibility calculated from the measurements were −3.5823 × 10{sup −3} cm/W and 2.3762 × 10{sup −6} esu respectively. The crystal was shown to be highly transparent above 366 nm by UV–vis spectroscopy and a yellow fluorescence was observed from PL spectrum. The TG–DTA and DSC analyses showed that the crystal is thermally stable up to 117.4 °C. The crystals were characterized by dielectric, etching and microhardness studies.
Growth and characterization of Piperazinium adipate: A third order NLO single crystal
NASA Astrophysics Data System (ADS)
Dhanalakshmi, B.; Ponnusamy, S.; Muthamizhchelvan, C.; Subhashini, V.
2015-09-01
Good quality single crystals of Piperazinium adipate were grown from aqueous solution at room temperature by slow solvent evaporation method. The crystal belongs to triclinic crystal system with centrosymmetric space group P 1 bar . Various functional groups present in the title compound were identified through FTIR, FTRaman and FTNMR spectral analyses. The UV-vis absorption studies of the crystal showed that the crystal is highly transparent in the entire visible range above 210 nm. The PL emission spectrum recorded at an excitation wavelength of 245 nm depicted a broad blue emission centered at 475 nm. The crystal is thermally stable upto 215 °C as found by TG-DTA and DSC analyses. The third-order nonlinear optical behavior of the title crystal was studied using Z-scan measurements. The negative nonlinear refractive index (n2) of the crystal suggested self-defocusing effect. The nonlinear absorption coefficient (β) and third order nonlinear optical susceptibility (χ(3)) were also calculated from the measurements.
Measurement of third-order elastic constants and applications to loaded structural materials.
Takahashi, Sennosuke; Motegi, Ryohei
2015-01-01
The objective of this study is to obtain the propagation velocity of an elastic wave in a loaded isotropic solid and to show the usefulness of the third-order elastic constant in determining properties of practical materials. As is well known, the infinitesimal elastic theory is unable to express the influence of stress on elastic wave propagating in loaded materials. To solve this problem, the authors derive an equation of motion for elastic wave in a finitely deformed state and use the Lagrangian description where the state before deformation is used as a reference, and Murnaghans finite deformation theory for the unidirectional deformed isotropic solid. Ordinary derivatives were used for the mathematical treatment and although the formulas are long the content is simple. The theory is applied to the measurement of the third-order elastic constants of common steels containing carbon of 0.22 and 0.32 wt%. Care is taken in preparing specimens to precise dimensions, in properly adhering of transducer to the surface of the specimen, and in having good temperature control during the measurements to obtain precise data. As a result, the stress at various sites in the structural materials could be estimated by measuring the elastic wave propagation times. The results obtained are graphed for illustration.
Regenerator performance in a Vuilleumier refrigerator compared with a third-order numerical model
NASA Technical Reports Server (NTRS)
Bradley, P. E.; Radebaugh, Ray; Gary, John
1991-01-01
A three-stage Vuilleumier refrigerator was used to measure the performance of various third stage regenerators. The refrigerator operates between 2.5 and 5.0 Hz and, depending on the material used in the third stage regenerator, achieves temperatures of 8 to 20 K at the cold end of the third stage. This paper presents a comparison of regenerator performance for four regenerator materials: 229 micron diameter spheres of Pb(+)5 pct Sb, 229 micron diameter spheres of brass, 216 micron irregularly-shaped GdRh powder, and a mixture of 229 microns and 762 microns diameter spheres of Pb(+5) pct Sb. The experimental results are compared with a first-order model that neglects the void volume within the regenerator and with a third-order model that considers the effect of pressure oscillations in the regenerator void volume. Experimental results indicate that regenerator losses are dominated by the pressure oscillation in the void volume rather than the mass flow through the temperature gradient in the regenerator. These results are consistent with the third-order numerical model. This model shows that the heat capacity of the gas in the void space as well as the heat capacity of the matrix influences the regenerator performance.
Top eigenvalue of a random matrix: large deviations and third order phase transition
NASA Astrophysics Data System (ADS)
Majumdar, Satya N.; Schehr, Grégory
2014-01-01
We study the fluctuations of the largest eigenvalue λmax of N × N random matrices in the limit of large N. The main focus is on Gaussian β ensembles, including in particular the Gaussian orthogonal (β = 1), unitary (β = 2) and symplectic (β = 4) ensembles. The probability density function (PDF) of λmax consists, for large N, of a central part described by Tracy-Widom distributions flanked, on both sides, by two large deviation tails. While the central part characterizes the typical fluctuations of λmax—of order {O}(N^{-2/3}) —the large deviation tails are instead associated with extremely rare fluctuations—of order {O}(1). Here we review some recent developments in the theory of these extremely rare events using a Coulomb gas approach. We discuss in particular the third order phase transition which separates the left tail from the right tail, a transition akin to the so-called Gross-Witten-Wadia phase transition found in 2-d lattice quantum chromodynamics. We also discuss the occurrence of similar third order transitions in various physical problems, including non-intersecting Brownian motions, conductance fluctuations in mesoscopic physics and entanglement in a bipartite system.
Perception of second- and third-order orientation signals and their interactions
Victor, Jonathan D.; Thengone, Daniel J.; Conte, Mary M.
2013-01-01
Orientation signals, which are crucial to many aspects of visual function, are more complex and varied in the natural world than in the stimuli typically used for laboratory investigation. Gratings and lines have a single orientation, but in natural stimuli, local features have multiple orientations, and multiple orientations can occur even at the same location. Moreover, orientation cues can arise not only from pairwise spatial correlations, but from higher-order ones as well. To investigate these orientation cues and how they interact, we examined segmentation performance for visual textures in which the strengths of different kinds of orientation cues were varied independently, while controlling potential confounds such as differences in luminance statistics. Second-order cues (the kind present in gratings) at different orientations are largely processed independently: There is no cancellation of positive and negative signals at orientations that differ by 45°. Third-order orientation cues are readily detected and interact only minimally with second-order cues. However, they combine across orientations in a different way: Positive and negative signals largely cancel if the orientations differ by 90°. Two additional elements are superimposed on this picture. First, corners play a special role. When second-order orientation cues combine to produce corners, they provide a stronger signal for texture segregation than can be accounted for by their individual effects. Second, while the object versus background distinction does not influence processing of second-order orientation cues, this distinction influences the processing of third-order orientation cues. PMID:23532909
Third order intermodulation distortion in HTS Josephson Junction downconverter at 12GHz
Suzuki, Katsumi; Hayashi, Kunihiko; Fujimoto, Manabu; Yamaguchi, Keiichi; Yoshikawa, Shuichi; Enomoto, Youichi
1994-12-31
Here the authors first report on the microwave characteristics of the third order intermodulation distortion(IMD3) in High-Tc Superconductor (HTS) Josephson Junction (JJ) Downconverter at 12GHz. They have successfully developed high quality nonlinear YBCO microbridge Josephson junctions for such an active MMIC as a mixer with RF, LO, IF and bias filters, which have been fabricated on (100) MgO substrates with 20mm x 20mm x 0.5mm dimensions. The minimum conversion loss of the JJ mixer is 11 dB at very small local microwave input power LO= {minus}20dBm which is two order less than Schottky diode mixer. Consequently, this small optimum LO power gives the small RF input power at which the output IF power of the YBCO mixer saturates. Two-tone third-order intercept point(IP3) performance is a significantly important figure of merit typically used to define linearity of devices and circuits. The RF input power = {minus}15dBm at the IP3 point is obtained for the YBCO mixer at 15K and LO = 10.935GHz with {minus}22dBm. The have successfully measured the dependence of IMD3 on temperature, bias current and LO power.
Lee, Lloyd L
2011-11-28
The third-order Ornstein-Zernike equation (OZ3) is used in the construction of a bridge functional that improves over conventional liquid-theory closures (for example, the hypernetted chain or the Percus-Yevick equations). The OZ3 connects the triplet direct correlation C((3)) to the triplet total correlation h((3)). By invoking the convolution approximation of Jackson and Feenberg, we are able to express the third-order bridge function B(3) as a functional of the indirect correlation γ. The resulting expression is generalized to higher-order bridge terms. This new closure is tested on the adsorption of Lennard-Jones fluid on planar hard surfaces by calculating the density profiles and comparing with Monte Carlo simulations. Particular attention is paid to the cases where molecular depletion on the substrate is evident. The results prove to be highly accurate and improve over conventional closures.
NASA Astrophysics Data System (ADS)
Antony Raj, A.; Gunaseelan, R.; Sagayaraj, P.
2014-12-01
The third order nonlinear optical, electric and dielectric properties of an organic stilbazolium derivative of 4-N,N-dimethylamino-N‧-methylstilbazolium p-methoxybenzenesulfonate (DSMOS) crystal are reported. The nonlinear refractive index (n2), two photon absorption coefficient (β) and third order optical susceptibility χ(3) have been measured by Z-scan technique using Gaussian beam from the Nd:YAG laser at 1064 nm. The results show a large negative nonlinear refractive index (n2 = -1.122 × 10-9 cm2/W) with a molecular two photon absorption coefficient β value of 3.625 × 10-6 cm/W. The low dielectric constant observed in the high frequency region indicates the suitability of the sample for electro-optic applications. The surface features are also investigated by atomic force microscopy (AFM).
Static and dynamic half-life and lifetime molecular turnover of enzymes.
Miyawaki, Osato; Kanazawa, Tsukasa; Maruyama, Chika; Dozen, Michiko
2017-01-01
The static half-life of an enzyme is the half-life of a free enzyme not working without substrate and the dynamic half-life is that of an active enzyme working with plenty amount of substrate. These two half-lives were measured and compared for glucoamylase (GA) and β-galactosidase (BG). The dynamic half-life was much longer than the static half-life by one to three orders of magnitude for both enzymes. For BG, the half-life of the enzyme physically entrapped in a membrane reactor was also measured. In this case also, the half-life of BG in the membrane reactor was much longer than the free enzyme without substrate. These results suggest the large difference in stabilities between the free enzyme and the enzyme-substrate complex. This may be related to the natural enzyme metabolism. According to the difference in half-life, the lifetime molecular turnover (LMT), which is the number of product molecules produced by a single molecule of enzyme until it loses its activity completely, was much higher by one to four orders of magnitude for the active enzyme than the free enzyme. The concept of LMT, proposed here, will be important in bioreactor operations with or without immobilization. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Varadarajan, R.; Dapp, E.K.; Rimnac, C.M.
2013-01-01
Fracture of Ultra High Molecular Weight Polyethylene (UHMWPE) components used in total joint replacements is a clinical concern. UHMWPE materials exhibits stable crack growth under static loading, therefore, their fracture resistance is generally characterized using the J-R curve. The multiple specimen method recommended by ASTM for evaluation of the J-R curve for polymers is time and material intensive. In this study, the applicability of a single specimen method based on load normalization to predict J-R curves of UHMWPE materials is evaluated. The normalization method involves determination of a deformation function. In this study, the J-R curves obtained using a power law based deformation function and the LMN curve based deformation function were compared. The results support the use of the power law based deformation function when using the single specimen approach to predict J-R curves for UHMWPE materials. PMID:23390325
Varadarajan, R; Dapp, E K; Rimnac, C M
2008-04-01
Fracture of Ultra High Molecular Weight Polyethylene (UHMWPE) components used in total joint replacements is a clinical concern. UHMWPE materials exhibits stable crack growth under static loading, therefore, their fracture resistance is generally characterized using the J-R curve. The multiple specimen method recommended by ASTM for evaluation of the J-R curve for polymers is time and material intensive. In this study, the applicability of a single specimen method based on load normalization to predict J-R curves of UHMWPE materials is evaluated. The normalization method involves determination of a deformation function. In this study, the J-R curves obtained using a power law based deformation function and the LMN curve based deformation function were compared. The results support the use of the power law based deformation function when using the single specimen approach to predict J-R curves for UHMWPE materials.
Yan, Xiao-Qing; Liu, Zhi-Bo; Zhang, Xiao-Liang; Zang, Wei-Ping; Tian, Jian-Guo
2010-05-10
The normal elliptically polarized light Z-scan method is modified by adding a quarter-wave plate and an analyzer before the detector. The normalized transmittance formulas of modified elliptically polarized light Z-scan are obtained for media with negligible nonlinear absorption. Compared with normal linearly and elliptically polarized light Z-scan methods, an increase of sensitivity by a factor of larger than 4 is achieved for the real part of third-order susceptibility component's measurements using this modified elliptically polarized light Z-scan method. The analytical results are verified by studying the real part of independent susceptibility components of CS(2) liquid. Moreover, the potential application for cross-polarized wave generation is discussed. (c) 2010 Optical Society of America.
Third-order perturbation theory for van der Waals interaction coefficients
Tang Liyan; Shi Tingyun; Yan Zongchao; Mitroy, J.
2011-11-15
The third-order expression for the dispersion interaction between two atoms is written as a sum over lists of transition matrix elements. Particular attention is given to the C{sub 9}/R{sup 9} interaction which occurs in the homonuclear case when one atom is in an S state and the other is in a P state. Numerical values of the C{sub 9} coefficient are given for the homonuclear alkali-metal dimers. The size of the C{sub 9}:C{sub 3} dispersion coefficient ratio increases for the heavier alkali-metal atoms. The C{sub 11} and C{sub 13} coefficients between two helium atoms and lithium atoms in their ground states are also given.
Yahia, Mouna Ben; Orhan, Emmanuelle; Beltrán, Armando; Masson, Olivier; Merle-Méjean, Thérèse; Mirgorodski, Andreï; Thomas, Philippe
2008-09-04
Density functional theory was used to estimate the third-order hypersusceptibility chi (3) of the alpha-TeO2 paratellurite (as a model structure for TeO2 glass) and the same value for alpha-SiO2 cristobalite (as a model structure for glassy silica). The attempt was made to gain a physical insight into the nature of the extraordinarily high hypersusceptibility of TeO2 glass. A finite field perturbation method implemented in the CRYSTAL code with the "sawtooth" approach was employed. The chi (3) values calculated for alpha-TeO2 were found to be of the same order as that measured for TeO2 glass and much higher than the values computed for alpha-SiO2 which, in turn, were close to that of glassy silica.
Efficient Third-Order Distributed Feedback Laser with Enhanced Beam Pattern
NASA Technical Reports Server (NTRS)
Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor); Kao, Tsung-Yu (Inventor)
2015-01-01
A third-order distributed feedback laser has an active medium disposed on a substrate as a linear array of segments having a series of periodically spaced interstices therebetween and a first conductive layer disposed on a surface of the active medium on each of the segments and along a strip from each of the segments to a conductive electrical contact pad for application of current along a path including the active medium. Upon application of a current through the active medium, the active medium functions as an optical waveguide, and there is established an alternating electric field, at a THz frequency, both in the active medium and emerging from the interstices. Spacing of adjacent segments is approximately half of a wavelength of the THz frequency in free space or an odd integral multiple thereof, so that the linear array has a coherence length greater than the length of the linear array.
Oscillation quenching in third order phase locked loop coupled by mean field diffusive coupling
NASA Astrophysics Data System (ADS)
Chakraborty, S.; Dandapathak, M.; Sarkar, B. C.
2016-11-01
We explored analytically the oscillation quenching phenomena (amplitude death and parameter dependent inhomogeneous steady state) in a coupled third order phase locked loop (PLL) both in periodic and chaotic mode. The phase locked loops were coupled through mean field diffusive coupling. The lower and upper limits of the quenched state were identified in the parameter space of the coupled PLL using the Routh-Hurwitz technique. We further observed that the ability of convergence to the quenched state of coupled PLLs depends on the design parameters. For identical systems, both the systems converge to the homogeneous steady state, whereas for non-identical parameter values they converge to an inhomogeneous steady state. It was also observed that for identical systems, the quenched state is wider than the non-identical case. When the system parameters are so chosen that each isolated loop is chaotic in nature, we observe narrowing down of the quenched state. All these phenomena were also demonstrated through numerical simulations.
Third-order voltage-mode active-C band pass filter
NASA Astrophysics Data System (ADS)
Ranjan, Ashish; Ghosh, Mourina; Paul, Sajal K.
2015-05-01
In this research article, a new third-order voltage-mode active-C asymmetrical band pass filter is proposed. It uses three numbers of current-controlled current conveyors and three numbers of equal-valued capacitors. The topology has the following important features: uses only three active elements, uses three capacitors, uses all grounded capacitors and no resistor is suitable for integrated circuit design, there is no matching constraint, high input impedance, low output impedance, central frequency can easily be electronically controlled by bias current, and frequency response is asymmetrical in nature. The application of the proposed topology in the realisation of a voltage-mode sixth-order symmetrical band pass filter has been demonstrated. The workability of the proposed topology and sixth-order filter has been confirmed by simulation results using 0.35-µm Austria Micro Systems complementary metal oxide semiconductor technology.
Third-order nonlinear optical response in quantum dot-metal nanoparticle hybrid structures
NASA Astrophysics Data System (ADS)
Liu, X. N.; Yao, D. Z.; Zhou, H. M.; Chen, F.; Xiong, G. G.
2013-12-01
Third-order nonlinear optical response of a semiconductor quantum dot, modulated by the metal nanoparticle (MNP), has been studied by using the effective mass and the rotating wave approximation. Considering multiple effects in the local and nonlocal optical response of the MNP, the dependence of the dispersion and the absorption on the size of the hybrid system are investigated in detail. By controlling the geometrical parameters of the hybrid structure and the direction of the electric field polarization, a significant enhancement of the nonlinear response is shown. The enhancement factor is nearly two orders of the magnitude, which is consistent with the experiment. Compared to the results obtained with the local effect, the center frequency shows blueshift obviously in the case of the nonlocal effect. In particular, the presence of the MNP leads to a strong absorption band appearance, which promises applications in the field of light transmission and the optical switching.
NASA Technical Reports Server (NTRS)
Schlesinger, R. E.
1985-01-01
The impact of upstream-biased corrections for third-order spatial truncation error on the stability and phase error of the two-dimensional Crowley combined advective scheme with the cross-space term included is analyzed, putting primary emphasis on phase error reduction. The various versions of the Crowley scheme are formally defined, and their stability and phase error characteristics are intercompared using a linear Fourier component analysis patterned after Fromm (1968, 1969). The performances of the schemes under prototype simulation conditions are tested using time-dependent numerical experiments which advect an initially cone-shaped passive scalar distribution in each of three steady nondivergent flows. One such flow is solid rotation, while the other two are diagonal uniform flow and a strongly deformational vortex.
Ultrafast control of third-order optical nonlinearities in fishnet metamaterials
NASA Astrophysics Data System (ADS)
Shorokhov, Alexander S.; Okhlopkov, Kirill I.; Reinhold, Jörg; Helgert, Christian; Shcherbakov, Maxim R.; Pertsch, Thomas; Fedyanin, Andrey A.
2016-06-01
Nonlinear photonic nanostructures that allow efficient all-optical switching are considered to be a prospective platform for novel building blocks in photonics. We performed time-resolved measurements of the photoinduced transient third-order nonlinear optical response of a fishnet metamaterial. The mutual influence of two non-collinear pulses exciting the magnetic resonance of the metamaterial was probed by detecting the third-harmonic radiation as a function of the time delay between pulses. Subpicosecond-scale dynamics of the metamaterial’s χ(3) was observed; the all-optical χ(3) modulation depth was found to be approximately 70% at a pump fluence of only 20 μJ/cm2.
Second- and third-order upwind difference schemes for hyperbolic conservation laws
NASA Technical Reports Server (NTRS)
Yang, J. Y.
1984-01-01
Second- and third-order two time-level five-point explicit upwind-difference schemes are described for the numerical solution of hyperbolic systems of conservation laws and applied to the Euler equations of inviscid gas dynamics. Nonliner smoothing techniques are used to make the schemes total variation diminishing. In the method both hyperbolicity and conservation properties of the hyperbolic conservation laws are combined in a very natural way by introducing a normalized Jacobian matrix of the hyperbolic system. Entropy satisfying shock transition operators which are consistent with the upwind differencing are locally introduced when transonic shock transition is detected. Schemes thus constructed are suitable for shockcapturing calculations. The stability and the global order of accuracy of the proposed schemes are examined. Numerical experiments for the inviscid Burgers equation and the compressible Euler equations in one and two space dimensions involving various situations of aerodynamic interest are included and compared.
The use of a squid third order spatial gradiometer to measure magnetic fields of the brain.
Weinberg, H; Brickett, P A; Vrba, J; Fife, A A; Burbank, M B
1984-01-01
It appears to be clear from the results that the third order gradiometer is able to detect small biomagnetic signals from the brain which are related to evoked potentials and spontaneous electrical activity. The instrument operates reasonably well within a noisy environment, however further development is necessary to balance the first gradient. We intend to pursue this direction with software systems. Some of the data presented suggest that components of MEG evoked activity may change independently of EEG. One interpretation which may derive from this is that the same current dipoles are probably not responsible for the entire configuration of evoked fields. This interpretation is consistent with EEG evidence which indicates that analogous components in the evoked potential may vary independently as a function of stimulus parameters and information processing. Perhaps a model of magnetic dipoles due to small current loops would be more compatible with the electrophysiological data.
A fluctuation method to calculate the third order elastic constants in crystalline solids
Chen, Zimu; Qu, Jianmin
2015-05-28
This paper derives exact expressions of the isothermal third order elastic constants (TOE) in crystalline solids in terms of the kinetic and potential energies of the system. These expressions reveal that the TOE constants consist of a Born component and a relaxation component. The Born component is simply the third derivative of the system's potential energy with respect to the deformation, while the relaxation component is related to the non-uniform rearrangements of the atoms when the system is subject to a macroscopic deformation. Further, based on the general expressions derived here, a direct (fluctuation) method of computing the isothermal TOE constants is developed. Numerical examples of using this fluctuation method are given to compute the TOE constants of single crystal iron.
Ultrafast control of third-order optical nonlinearities in fishnet metamaterials
Shorokhov, Alexander S.; Okhlopkov, Kirill I.; Reinhold, Jörg; Helgert, Christian; Shcherbakov, Maxim R.; Pertsch, Thomas; Fedyanin, Andrey A.
2016-01-01
Nonlinear photonic nanostructures that allow efficient all-optical switching are considered to be a prospective platform for novel building blocks in photonics. We performed time-resolved measurements of the photoinduced transient third-order nonlinear optical response of a fishnet metamaterial. The mutual influence of two non-collinear pulses exciting the magnetic resonance of the metamaterial was probed by detecting the third-harmonic radiation as a function of the time delay between pulses. Subpicosecond-scale dynamics of the metamaterial’s χ(3) was observed; the all-optical χ(3) modulation depth was found to be approximately 70% at a pump fluence of only 20 μJ/cm2. PMID:27335268
Direct Object Recognition Using No Higher Than Second or Third Order Statistics of the Image.
1995-02-01
i(N 0 2;1 +N 0 0;3) = ei[(N3;0 + N1;2) i(N2;1 + N0;3)] eiI21 (13) where Npq and N 0 rs are respective third order moments of the normalized...perturbation L: Lij X r;s (ijrs 0 rs + ij rs m 0 rs ) (47) where ; are coecients that are exclusively com- posed of the components ~A0ij , ~m0rs...hand side, that are composed of coecient epq ’s,frs’s, and elements of U 0 , and pij in the right hand side. Solving for equation (62) we get: cos
Third order elastic constants and Rayleigh wave dispersion of shot-peened aero-engine materials
NASA Astrophysics Data System (ADS)
Rjelka, M.; Barth, M.; Reinert, S.; Koehler, B.; Bamberg, J.; Baron, H.-U.
2012-05-01
Mechanically high stressed components used in aero-engines are made of highstrength alloys like IN718 and Ti6246. Additionally, they are surface treated by shot-peening. This introduces compressive residual stress to minimize the material's sensitivity to fatigue or stress corrosion failure mechanisms, resulting in improved performance and increased lifetime of components. Besides that, cold work is introduced in an amount depending on the peening parameters. To determine the remaining lifetime of critical aero engine components, a quantitative non-destructive determination of compressive stresses is required. It was shown that the surface treatment of aero engine alloys can be characterized by broadband Rayleigh wave dispersion but the relative contributions of compressive stress and cold work remained an open point. The present paper presents measurements of the second and third order elastic constants (TOEC) of IN718 and Ti6246. By that the stress contribution to the surface wave dispersion can be estimated.
Oscillation quenching in third order phase locked loop coupled by mean field diffusive coupling.
Chakraborty, S; Dandapathak, M; Sarkar, B C
2016-11-01
We explored analytically the oscillation quenching phenomena (amplitude death and parameter dependent inhomogeneous steady state) in a coupled third order phase locked loop (PLL) both in periodic and chaotic mode. The phase locked loops were coupled through mean field diffusive coupling. The lower and upper limits of the quenched state were identified in the parameter space of the coupled PLL using the Routh-Hurwitz technique. We further observed that the ability of convergence to the quenched state of coupled PLLs depends on the design parameters. For identical systems, both the systems converge to the homogeneous steady state, whereas for non-identical parameter values they converge to an inhomogeneous steady state. It was also observed that for identical systems, the quenched state is wider than the non-identical case. When the system parameters are so chosen that each isolated loop is chaotic in nature, we observe narrowing down of the quenched state. All these phenomena were also demonstrated through numerical simulations.
Third-order polynomial model for analyzing stickup state laminated structure in flexible electronics
NASA Astrophysics Data System (ADS)
Meng, Xianhong; Wang, Zihao; Liu, Boya; Wang, Shuodao
2017-05-01
Laminated hard-soft integrated structures play a significant role in the fabrication and development of flexible electronics devices. Flexible electronics have advantageous characteristics such as soft and light-weight, can be folded, twisted, flipped inside-out, or be pasted onto other surfaces of arbitrary shapes. In this paper, an analytical model is presented to study the mechanics of laminated hard-soft structures in flexible electronics under a stickup state. Third-order polynomials are used to describe the displacement field, and the principle of virtual work is adopted to derive the governing equations and boundary conditions. The normal strain and the shear stress along the thickness direction in the bi-material region are obtained analytically, which agree well with the results from finite element analysis. The analytical model can be used to analyze stickup state laminated structures, and can serve as a valuable reference for the failure prediction and optimal design of flexible electronics in the future.
NASA Astrophysics Data System (ADS)
Castro, Hemerson P. S.; Wender, Heberton; Alencar, Márcio A. R. C.; Teixeira, Sergio R.; Dupont, Jairton; Hickmann, Jandir M.
2013-11-01
The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.
Castro, Hemerson P. S.; Alencar, Márcio A. R. C.; Hickmann, Jandir M.; Wender, Heberton; Teixeira, Sergio R.; Dupont, Jairton
2013-11-14
The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.
Hopf bifurcation and chaos in a third-order phase-locked loop
NASA Astrophysics Data System (ADS)
Piqueira, José Roberto C.
2017-01-01
Phase-locked loops (PLLs) are devices able to recover time signals in several engineering applications. The literature regarding their dynamical behavior is vast, specifically considering that the process of synchronization between the input signal, coming from a remote source, and the PLL local oscillation is robust. For high-frequency applications it is usual to increase the PLL order by increasing the order of the internal filter, for guarantying good transient responses; however local parameter variations imply structural instability, thus provoking a Hopf bifurcation and a route to chaos for the phase error. Here, one usual architecture for a third-order PLL is studied and a range of permitted parameters is derived, providing a rule of thumb for designers. Out of this range, a Hopf bifurcation appears and, by increasing parameters, the periodic solution originated by the Hopf bifurcation degenerates into a chaotic attractor, therefore, preventing synchronization.
Photoacoustic Z-scan for the measurement of third-order nonlinear absorption coefficient
NASA Astrophysics Data System (ADS)
Yelleswarapu, Chandra S.; Kothapalli, Sri-Rajasekhar; Rao, D. V. G. L. N.
2011-03-01
The third order optical nonlinearities cover a vast and diverse area in nonlinear optics. The third order nonlinear susceptibility χ(3) is a complex quantity and its real and imaginary components represent nonlinear refraction and nonlinear absorption, respectively. Measurement of these parameters is important for many practical applications. Z-scan is a simple optical technique for determining these characteristics with high accuracy. Here we present a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. In PAZ-scan, instead of measuring the transmitted optical signal as in the case of traditional Z-scan, we record the generated photoacoustic (PA) signal using a 10 MHz focused ultrasound transducer while the sample is translated along the focused laser beam. Since the photoacoustic signal strength is directly proportional to the optical absorption, PAZ-scan displays nonlinear behavior depicting the nonlinear optical absorption of the material. For reverse saturable absorber (RSA) materials, absorption and hence the PA signal increases with the increase of input intensity. Similarly for saturable absorber (SA) materials, absorption and the associated PA signal decreases with increase in input intensity. We studied the nonlinear absorption properties of SA and RSA materials. Our calculations of nonlinear absorption coefficient are in good agreement with conventional the Z-scan data.We believe that PAZ-scan will be a valuable tool for material characterization and has potential for applications in the fields of chemistry, physics, material science, biomedical, and manufacturing.
Third-order nonlinear and linear time-dependent dynamical diffraction of X-rays in crystals.
Balyan, Minas K
2016-07-01
For the first time the third-order nonlinear time-dependent Takagi's equations of X-rays in crystals are obtained and investigated. The third-order nonlinear and linear time-dependent dynamical diffraction of X-rays spatially restricted in the diffraction plane pulses in crystals is investigated theoretically. A method of solving the linear and the third-order nonlinear time-dependent Takagi's equations is proposed. Based on this method, results of analytical and numerical calculations for both linear and nonlinear diffraction cases are presented and compared.
NASA Astrophysics Data System (ADS)
Li, Wenchao; Yang, Jianyu; Huang, Yulin; Kong, Lingjiang
For Doppler parameter estimation of forward-looking SAR, the third-order Doppler parameter can not be neglected. In this paper, the azimuth signal of the transmitter fixed bistatic forward-looking SAR is modeled as a cubic polynomial phase signal (CPPS) and multiple time-overlapped CPPSs, and the modified cubic phase function is presented to estimate the third-order Doppler parameter. By combining the cubic phase function (CPF) with Radon transform, the method can give an accurate estimation of the third-order Doppler parameter. Simulations validate the effectiveness of the algorithm.
Molecular Modeling of Three Phase Contact for Static and Dynamic Contact Angle Phenomena
NASA Astrophysics Data System (ADS)
Malani, Ateeque; Amat, Miguel; Raghavanpillai, Anilkumar; Wysong, Ernest; Rutledge, Gregory
2012-02-01
Interfacial phenomena arise in a number of industrially important situations, such as repellency of liquids on surfaces, condensation, etc. In designing materials for such applications, the key component is their wetting behavior, which is characterized by three-phase static and dynamic contact angle phenomena. Molecular modeling has the potential to provide basic insight into the detailed picture of the three-phase contact line resolved on the sub-nanometer scale which is essential for the success of these materials. We have proposed a computational strategy to study three-phase contact phenomena, where buoyancy of a solid rod or particle is studied in a planar liquid film. The contact angle is readily evaluated by measuring the position of solid and liquid interfaces. As proof of concept, the methodology has been validated extensively using a simple Lennard-Jones (LJ) fluid in contact with an LJ surface. In the dynamic contact angle analysis, the evolution of contact angle as a function of force applied to the rod or particle is characterized by the pinning and slipping of the three phase contact line. Ultimately, complete wetting or de-wetting is observed, allowing molecular level characterization of the contact angle hysteresis.
Schneider, M; Soshnikov, D Yu; Holland, D M P; Powis, I; Antonsson, E; Patanen, M; Nicolas, C; Miron, C; Wormit, M; Dreuw, A; Trofimov, A B
2015-10-14
The valence-shell ionization spectrum of bromobenzene, as a representative halogen substituted aromatic, was studied using the non-Dyson third-order algebraic-diagrammatic construction [nD-ADC(3)] approximation for the electron propagator. This method, also referred to as IP-ADC(3), was implemented as a part of the Q-Chem program and enables large-scale calculations of the ionization spectra, where the computational effort scales as n(5) with respect to the number of molecular orbitals n. The IP-ADC(3) scheme is ideally suited for investigating low-lying ionization transitions, so fresh insight could be gained into the cationic state manifold of bromobenzene. In particular, the present IP-ADC(3) calculations with the cc-pVTZ basis reveal a whole class of low-lying low-intensity two-hole-one-particle (2h-1p) doublet and quartet states, which are relevant to various photoionization processes. The good qualitative agreement between the theoretical spectral profile for the valence-shell ionization transitions generated with the smaller cc-pVDZ basis set and the experimental photoelectron spectrum measured at a photon energy of 80 eV on the PLÉIADES beamline at the Soleil synchrotron radiation source allowed all the main features to be assigned. Some theoretical aspects of the ionization energy calculations concerning the use of various approximation schemes and basis sets are discussed.
Schneider, M.; Wormit, M.; Dreuw, A.; Soshnikov, D. Yu.; Trofimov, A. B.; Holland, D. M. P.; Powis, I.; Antonsson, E.; Patanen, M.; Nicolas, C.; Miron, C.
2015-10-14
The valence-shell ionization spectrum of bromobenzene, as a representative halogen substituted aromatic, was studied using the non-Dyson third-order algebraic-diagrammatic construction [nD-ADC(3)] approximation for the electron propagator. This method, also referred to as IP-ADC(3), was implemented as a part of the Q-Chem program and enables large-scale calculations of the ionization spectra, where the computational effort scales as n{sup 5} with respect to the number of molecular orbitals n. The IP-ADC(3) scheme is ideally suited for investigating low-lying ionization transitions, so fresh insight could be gained into the cationic state manifold of bromobenzene. In particular, the present IP-ADC(3) calculations with the cc-pVTZ basis reveal a whole class of low-lying low-intensity two-hole-one-particle (2h-1p) doublet and quartet states, which are relevant to various photoionization processes. The good qualitative agreement between the theoretical spectral profile for the valence-shell ionization transitions generated with the smaller cc-pVDZ basis set and the experimental photoelectron spectrum measured at a photon energy of 80 eV on the PLÉIADES beamline at the Soleil synchrotron radiation source allowed all the main features to be assigned. Some theoretical aspects of the ionization energy calculations concerning the use of various approximation schemes and basis sets are discussed.
NASA Astrophysics Data System (ADS)
Hohenstein, Edward G.; Parrish, Robert M.; Martínez, Todd J.
2012-07-01
Many approximations have been developed to help deal with the O(N4) growth of the electron repulsion integral (ERI) tensor, where N is the number of one-electron basis functions used to represent the electronic wavefunction. Of these, the density fitting (DF) approximation is currently the most widely used despite the fact that it is often incapable of altering the underlying scaling of computational effort with respect to molecular size. We present a method for exploiting sparsity in three-center overlap integrals through tensor decomposition to obtain a low-rank approximation to density fitting (tensor hypercontraction density fitting or THC-DF). This new approximation reduces the 4th-order ERI tensor to a product of five matrices, simultaneously reducing the storage requirement as well as increasing the flexibility to regroup terms and reduce scaling behavior. As an example, we demonstrate such a scaling reduction for second- and third-order perturbation theory (MP2 and MP3), showing that both can be carried out in O(N4) operations. This should be compared to the usual scaling behavior of O(N5) and O(N6) for MP2 and MP3, respectively. The THC-DF technique can also be applied to other methods in electronic structure theory, such as coupled-cluster and configuration interaction, promising significant gains in computational efficiency and storage reduction.
NASA Astrophysics Data System (ADS)
Chen, Feifei; Dai, Shixun; Xu, Tiefeng; Shen, Xiang; Lin, Changgui; Nie, Qiuhua; Liu, Chao; Heo, Jong
2011-09-01
Ellipsoidal gold nanoparticles embedded bismuthate glasses have been prepared via a facile melt-annealing approach. Femtosecond Z-scan measurement shows that the nanocomposites exhibit a maximum third-order nonlinear susceptibility χ(3) of 4.88 × 10-10 esu at 800 nm, which is two orders higher than that of the host glass. Optical Kerr shutter measurement demonstrates ultrafast response time (in scale of sub-picosecond) of the intraband transition enhanced third-order nonlinearities.
NASA Astrophysics Data System (ADS)
Šprlák, Michal; Novák, Pavel
2017-02-01
New spherical integral formulas between components of the second- and third-order gravitational tensors are formulated in this article. First, we review the nomenclature and basic properties of the second- and third-order gravitational tensors. Initial points of mathematical derivations, i.e., the second- and third-order differential operators defined in the spherical local North-oriented reference frame and the analytical solutions of the gradiometric boundary-value problem, are also summarized. Secondly, we apply the third-order differential operators to the analytical solutions of the gradiometric boundary-value problem which gives 30 new integral formulas transforming (1) vertical-vertical, (2) vertical-horizontal and (3) horizontal-horizontal second-order gravitational tensor components onto their third-order counterparts. Using spherical polar coordinates related sub-integral kernels can efficiently be decomposed into azimuthal and isotropic parts. Both spectral and closed forms of the isotropic kernels are provided and their limits are investigated. Thirdly, numerical experiments are performed to test the consistency of the new integral transforms and to investigate properties of the sub-integral kernels. The new mathematical apparatus is valid for any harmonic potential field and may be exploited, e.g., when gravitational/magnetic second- and third-order tensor components become available in the future. The new integral formulas also extend the well-known Meissl diagram and enrich the theoretical apparatus of geodesy.
Karakas, Asli; Unver, Hüseyin
2010-05-01
(E)-N-(4-Nitrobenzylidene)-2,6-dimethylaniline (1) and (E)-N-(4-nitrobenzylidene)-2,3-dimethylaniline (2) have been synthesized. The crystal structures of both compounds have been defined by X-ray diffraction analysis. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450nm, showing good optical transparency to the visible light. To provide an insight into the microscopic third-order nonlinear optical (NLO) properties of the investigated molecules, both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (alpha) and second hyperpolarizabilities (gamma) at lambda=825-1125nm and 1050-1600nm wavelength areas have been computed using time-dependent Hartree-Fock (TDHF) method. According to the ab initio calculation results, the title molecules exhibit second hyperpolarizabilities with non-zero values, implying microscopic third-order NLO behavior.
Enhanced Nonclassical Third-Order Spatial Intensity Correlations in Three-Beam Interferences<
NASA Astrophysics Data System (ADS)
Richter, Th.
The joint probability of detecting simultaneously three photons at two and three points in the superposition field of three independent plane waves with the same frequency but random phases is calculated and compared with the results of a classical wave theory. Significant differences occur for sufficiently weak fields. We find that the differences between the quantum mechanical and classical predictions concerning the third order intensity correlation functions are more pronounced in a three-beam than in a two-beam interference experiment.Translated AbstractDreistrahlinterferenzen und nichtklassische räumliche Intensitätskorrelationen dritter OrdnungDie Verbundwahrscheinlichkeit des gleichzeitigen Nachweises von drei Photonen an zwei bzw. drei verschiedenen Orten im Interferenzfeld dreier unabhängiger Lichtstrahlen mit statistisch fluktuierenden Phasen wird berechnet und mit den Aussagen der klassischen Theorie verglichen. Bedeutende Unterschiede treten bei sehr geringen Lichtintensitäten auf. Dabei sind diese Unterschiede bei einem Dreistrahlinterferenz-Experiment ausgeprägter als im Zweistrahl-Fall.
Synthesis And Third-order Nonlinear Optical Studies of Four-Coordinated Copper(I) Complexes
NASA Astrophysics Data System (ADS)
Kumar, H. C. Sampath; Rudresha, B. J.; Bhat, B. Ramachandra; Philip, Reji; Row, T. N. Guru
2011-10-01
Three Cu(I) halide complexes [Cu(L)(PPh3)X] (L = 1,10-phenanthroline, X = Cl (1), Br (2) and I (3), PPh3 = triphenylphosphine) have been synthesised and characterised by spectroscopic techniques. Further structure of the complex 1 was confirmed by single crystal X-ray diffraction analysis. The nonlinear optical properties of the complexes were investigated at 532 nm using single beam Z-scan technique with nanosecond laser pulses. The complexes showed strong optical limiting behavior due to effective three-photon absorption (3PA). The values of 3PA coefficients (γ) for 1, 2 and 3 were found to be 3.2×10-24 m3/W2, 6.0×10-25 m3/W2 and 1.2×10-23 m3/W2 respectively, which are comparable to good optical limiting materials. These studies demonstrate that the Ligand→copper coordinative bonds facilitate the polarization of the electronic π-system which optimizes the third-order NLO response in the reported complexes.
NASA Astrophysics Data System (ADS)
Lu, Yujie; Douraghy, Ali; Machado, Hidevaldo B.; Stout, David; Tian, Jie; Herschman, Harvey; Chatziioannou, Arion F.
2009-11-01
Bioluminescence imaging has been extensively applied to in vivo small animal imaging. Quantitative three-dimensional bioluminescent source information obtained by using bioluminescence tomography can directly and much more accurately reflect biological changes as opposed to planar bioluminescence imaging. Preliminary simulated and experimental reconstruction results demonstrate the feasibility and promise of bioluminescence tomography. However, the use of multiple approximations, particularly the diffusion approximation theory, affects the quality of in vivo small animal-based image reconstructions. In the development of new reconstruction algorithms, high-order approximation models of the radiative transfer equation and spectrally resolved data introduce new challenges to the reconstruction algorithm and speed. In this paper, an SP3-based (the third-order simplified spherical harmonics approximation) spectrally resolved reconstruction algorithm is proposed. The simple linear relationship between the unknown source distribution and the spectrally resolved data is established in this algorithm. A parallel version of this algorithm is realized, making BLT reconstruction feasible for the whole body of small animals especially for fine spatial domain discretization. In simulation validations, the proposed algorithm shows improved reconstruction quality compared with diffusion approximation-based methods when high absorption, superficial sources and detection modes are considered. In addition, comparisons between fine and coarse mesh-based BLT reconstructions show the effects of numerical errors in reconstruction image quality. Finally, BLT reconstructions using in vivo mouse experiments further demonstrate the potential and effectiveness of the SP3-based reconstruction algorithm.
Baseline-free estimation of residual fatigue life using a third order acoustic nonlinear parameter.
Amura, Mikael; Meo, Michele; Amerini, F
2011-10-01
Prediction of crack growth and fatigue life estimation of metals using linear/nonlinear acousto-ultrasound methods is an ongoing issue. It is known that by measuring nonlinear parameters, the relative accumulated fatigue damage can be evaluated. However, there is still a need to measure two crack propagation states to assess the absolute residual fatigue life. A procedure based on the measurement of a third-order acoustic nonlinear parameter is presented to assess the residual fatigue life of a metallic component without the need of a baseline. The analytical evaluation of how the cubic nonlinear-parameter evolves during crack propagation is presented by combining the Paris law to the Nazarov-Sutin crack equation. Unlike other developed models, the proposed model assumes a crack surface topology with variable geometrical parameters. Measurements of the cubic nonlinearity parameter on AA2024-T351 specimens demonstrated high sensitivity to crack propagation and excellent agreement with the predicted theoretical behavior. The advantages of using the cubic nonlinearity parameter for fatigue cracks on metals are discussed by comparing the relevant results of a quadratic nonlinear parameter. Then the methodology to estimate crack size and residual fatigue life without the need of a baseline is presented, and advantages and limitations are discussed.
NASA Astrophysics Data System (ADS)
Almeida, Juliana M. P.; da Silva, Diego S.; Kassab, Luciana R. P.; Zilio, Sergio C.; Mendonça, Cleber R.; De Boni, Leonardo
2014-02-01
This work reports on the third-order nonlinear properties and the response time of GeO2-Bi2O3 glass, as well as the effect of gold nanoparticles on these properties. The nonlinear refractive index spectrum and the nonlinear absorption coefficient were determined by the Z-scan technique, and the response time was obtained through Kerr gate measurements, using femtosecond pulses. The results show that the presence of gold nanoparticles causes a saturable absorption effect that is overcome by the two-photon absorption process at higher light intensities, for wavelengths within the plasmon band. We measured a constant value for the nonlinear refractive index (n2) for the visible and infrared regions, which was not affected by the presence of gold nanoparticles in the sample. However, the n2 value is one order of magnitude higher than the one for fused silica and 1.5 times better than PGO (PbO-GeO2) glasses. In addition, the response time of the induced birefringence for the samples with and without gold nanoparticles is faster than the pulse duration (220 fs), indicating an ultra-fast electronic process.
Third-order optical nonlinearity studies of bilayer Au/Ag metallic films
NASA Astrophysics Data System (ADS)
Mezher, M. H.; Chong, W. Y.; Zakaria, R.
2016-05-01
This paper presents nonlinear optical studies of bilayer metallic films of gold (Au) and silver (Ag) on glass substrate prepared using electron beam evaporation. The preparation of Au and Ag nanoparticles (NPs) on the substrate involved the use of electron beam deposition, then thermal annealing at 600 °C and 270 °C, respectively, to produce a randomly distributed layer of Au and a layer of Ag NPs. Observation of field-effect scanning electron microscope images indicated the size of the NPs. Details of the optical properties related to peak absorption of surface plasmon resonance of the nanoparticle were revealed by use of UV-Vis spectroscopy. The Z-scan technique was used to measure the nonlinear absorption and nonlinear refraction of the fabricated NP layers. The third-order nonlinear refractive index coefficients for Au and Ag are (-9.34 and -1.61) × 10-11 cm2 W-1 given lower n 2, in comparison with bilayer (Au and Ag) NPs at -1.24 × 10-10 cm2 W-1. The results show bilayer NPs have higher refractive index coefficients thus enhance the nonlinearity effects.
Stochastic, real-space, imaginary-time evaluation of third-order Feynman–Goldstone diagrams
Willow, Soohaeng Yoo; Hirata, So
2014-01-14
A new, alternative set of interpretation rules of Feynman–Goldstone diagrams for many-body perturbation theory is proposed, which translates diagrams into algebraic expressions suitable for direct Monte Carlo integrations. A vertex of a diagram is associated with a Coulomb interaction (rather than a two-electron integral) and an edge with the trace of a Green's function in real space and imaginary time. With these, 12 diagrams of third-order many-body perturbation (MP3) theory are converted into 20-dimensional integrals, which are then evaluated by a Monte Carlo method. It uses redundant walkers for convergence acceleration and a weight function for importance sampling in conjunction with the Metropolis algorithm. The resulting Monte Carlo MP3 method has low-rank polynomial size dependence of the operation cost, a negligible memory cost, and a naturally parallel computational kernel, while reproducing the correct correlation energies of small molecules within a few mE{sub h} after 10{sup 6} Monte Carlo steps.
Stochastic, real-space, imaginary-time evaluation of third-order Feynman-Goldstone diagrams
NASA Astrophysics Data System (ADS)
Willow, Soohaeng Yoo; Hirata, So
2014-01-01
A new, alternative set of interpretation rules of Feynman-Goldstone diagrams for many-body perturbation theory is proposed, which translates diagrams into algebraic expressions suitable for direct Monte Carlo integrations. A vertex of a diagram is associated with a Coulomb interaction (rather than a two-electron integral) and an edge with the trace of a Green's function in real space and imaginary time. With these, 12 diagrams of third-order many-body perturbation (MP3) theory are converted into 20-dimensional integrals, which are then evaluated by a Monte Carlo method. It uses redundant walkers for convergence acceleration and a weight function for importance sampling in conjunction with the Metropolis algorithm. The resulting Monte Carlo MP3 method has low-rank polynomial size dependence of the operation cost, a negligible memory cost, and a naturally parallel computational kernel, while reproducing the correct correlation energies of small molecules within a few mEh after 106 Monte Carlo steps.
Large enhancement of third-order nonlinear effects with a resonant all-dielectric metasurface
NASA Astrophysics Data System (ADS)
Jafar-Zanjani, Samad; Cheng, Jierong; Liberman, Vladimir; Chou, Jeffrey B.; Mosallaei, Hossein
2016-11-01
A novel low-profile nonlinear metasurface, consisting of a single-layer of all-dielectric material, is proposed and numerically investigated by a nonlinear full-wave finite-difference time-domain (FDTD) method. The proposed metasurface is transparent for low, and opaque for high values of incident light intensity. The metasurface design is broadly applicable to enhancement of intrinsic nonlinearities of any material with a sufficiently high refractive index contrast. We illustrate the ability of this design to enhance intrinsic nonlinear absorption of a transition metal oxide, vanadium pentoxide (V2O5), with resonant metasurface elements. The complex third-order nonlinear susceptibility (χ(3 )) for V2O5, representing both nonlinear refraction and absorption is considered in FDTD simulations. Our design achieves high initial transparency (>90%) for low incident light intensity. An order of magnitude decrease in the required input light intensity threshold for nonlinear response of the metasurface is observed in comparison with an unpatterend film. The proposed all-dielectric metasurface in this work is ultrathin and easy to fabricate. We envision a number of applications of this design for thin film coatings that offer protection against high-power laser radiation.
Third-order nonlinear optical properties of acid green 25 dye by Z–scan method
NASA Astrophysics Data System (ADS)
Jeyaram, S.; Geethakrishnan, T.
2017-03-01
Third-order nonlinear optical (NLO) properties of aqueous solutions of an anthraquinone dye (Acid green 25 dye, color index: 61570) have been studied by Z–scan method with a 5 mW continuous wave (CW) diode laser operating at 635 nm. The nonlinear refractive index (n2) and the absorption coefficient (β) have been evaluated respectively from the closed and open aperture Z–scan data and the values of these parameters are found to increase with increase in concentration of the dye solution. The negative sign of the observed nonlinear refractive index (n2) indicates that the aqueous solution of acid green 25 dye exhibits self-defocusing type optical nonlinearity. The mechanism of the observed nonlinear absorption (NLA) and nonlinear refraction (NLR) is attributed respectively to reverse saturable absorption (RSA) and thermal nonlinear effects. The magnitudes of n2 and β are found to be of the order of 10-7 cm2/W and 10-3 cm/W respectively. With these experimental results, the authors suggest that acid green 25 dye may have potential applications in nonlinear optics.
Third order optical nonlinear studies on highly conducting vertically aligned carbon nanoflakes
NASA Astrophysics Data System (ADS)
Singh, Mukesh; Kumar, Indrajeet; Khare, Alika; Agarwal, Pratima
2016-12-01
Third order optical nonlinearity of carbon nanoflakes were studied by modified single beam closed aperture Z-scan technique using a continuous wave He-Ne laser at 632.8 nm. Thin films of vertically aligned carbon nanoflakes were synthesized on corning glass substrate at substrate temperature of 400 °C by hot filament chemical vapor deposition. Films were characterized by scanning electron microscope and atomic force microscopy which confirmed that carbon nanoflakes were vertically aligned on the substrate. Temperature dependent electrical conductivity measurements in temperature range of 300-480 K under high vacuum (˜10-5 mbar) showed that conductivity of the films was increased almost linearly with increasing temperature with a weak temperature dependence. The negative temperature coefficient of resistance indicates semiconducting behavior of the films. Nonlinear refractive index coefficient (n 2) of the films was found to be of the order of 10-5 cm2 W-1, which can be important for the applications in the field of nonlinear photonics.
Exploiting multi-lead electrocardiogram correlations using robust third-order tensor decomposition
Dandapat, Samarendra
2015-01-01
In this Letter, a robust third-order tensor decomposition of multi-lead electrocardiogram (MECG) comprising of 12-leads is proposed to reduce the dimension of the storage data. An order-3 tensor structure is employed to represent the MECG data by rearranging the MECG information in three dimensions. The three-dimensions of the formed tensor represent the number of leads, beats and samples of some fixed ECG duration. Dimension reduction of such an arrangement exploits correlations present among the successive beats (intra-beat and inter-beat) and across the leads (inter-lead). The higher-order singular value decomposition is used to decompose the tensor data. In addition, multiscale analysis has been added for effective care of ECG information. It grossly segments the ECG characteristic waves (P-wave, QRS-complex, ST-segment and T-wave etc.) into different sub-bands. In the meantime, it separates high-frequency noise components into lower-order sub-bands which helps in removing noise from the original data. For evaluation purposes, we have used the publicly available PTB diagnostic database. The proposed method outperforms the existing algorithms where compression ratio is under 10 for MECG data. Results show that the original MECG data volume can be reduced by more than 45 times with acceptable diagnostic distortion level. PMID:26609416
Stochastic, real-space, imaginary-time evaluation of third-order Feynman-Goldstone diagrams.
Willow, Soohaeng Yoo; Hirata, So
2014-01-14
A new, alternative set of interpretation rules of Feynman-Goldstone diagrams for many-body perturbation theory is proposed, which translates diagrams into algebraic expressions suitable for direct Monte Carlo integrations. A vertex of a diagram is associated with a Coulomb interaction (rather than a two-electron integral) and an edge with the trace of a Green's function in real space and imaginary time. With these, 12 diagrams of third-order many-body perturbation (MP3) theory are converted into 20-dimensional integrals, which are then evaluated by a Monte Carlo method. It uses redundant walkers for convergence acceleration and a weight function for importance sampling in conjunction with the Metropolis algorithm. The resulting Monte Carlo MP3 method has low-rank polynomial size dependence of the operation cost, a negligible memory cost, and a naturally parallel computational kernel, while reproducing the correct correlation energies of small molecules within a few mEh after 10(6) Monte Carlo steps.
Kinetics of third-order nonlinear optical susceptibilities in alkynyl ruthenium complexes
NASA Astrophysics Data System (ADS)
Migalska-Zalas, A.; Luc, J.; Sahraoui, B.; Kityk, I. V.
2006-07-01
Kinetics of third-order optical susceptibilities obtained for a new series of alkynyl ruthenium complexes was investigated in using pump-dependent transmission experiment and the degenerate four-wave mixing (DFWM) technique. We investigate electron rich σ-acetylide ruthenium complexes in which the d-transition metal is incorporated in the same plane as the π-system of formyl alkynyl ligands. The obtained results show that the presence of a bilaterally ligands leads to substantial increase of the χ<3>. The maximally achieved third optical susceptibility was χ<3> = 0.9 × 10 -20 m 2 V -2 at λ = 0.53 μm for chloroform solution concentration 0.4 mol l -1. The value of second-order optical hyperpolarizabilities γ for the investigated compounds were four orders of magnitude larger compared to the known values of CS 2. The quasi-periodic relaxation time kinetics of the DFWM with period about 7 ns was found after switching off the pumping beams. Such kinetics of the DFWM is explained by tunnelling between the occupied d-transition metal levels and electron-phonon trapping levels after interruption of the pumping signals.
Effects of the third-order dispersion on continuous waves in complex potentials
NASA Astrophysics Data System (ADS)
Liu, Bin; Li, Lu; Malomed, Boris A.
2017-06-01
A class of constant-amplitude (CA) solutions of the nonlinear Schrödinger equation with the third-order spatial dispersion (TOD) and complex potentials are considered. The system can be implemented in specially designed planar nonlinear optical waveguides carrying a distribution of local gain and loss elements, in a combination with a photonic-crystal structure. The complex potential is built as a solution of the inverse problem, which predicts the potential supporting a required phase-gradient structure of the CA state. It is shown that the diffraction of truncated CA states with a correct phase structure can be strongly suppressed. The main subject of the analysis is the modulational instability (MI) of the CA states. The results show that the TOD term tends to attenuate the MI. In particular, simulations demonstrate a phenomenon of weak stability, which occurs when the linear-stability analysis predicts small values of the MI growth rate. The stability of the zero state, which is a nontrivial issue in the framework of the present model, is studied too.
A third-order mode high frequency biosensor with atomic resolution.
Cai, Hua-Lin; Yang, Yi; Chen, Xiao; Mohammad, Mohammad Ali; Ye, Tian-Xiang; Guo, Cang-Ran; Yi, Li-Ting; Zhou, Chang-Jian; Liu, Jing; Ren, Tian-Ling
2015-09-15
An atomic resolution ultra-high sensitivity surface acoustic wave (SAW) biosensor for DNA sequences and cells detection is proposed. Interdigitated transducers (IDTs) fabricated on LiNbO3 substrate achieve a high quality factor (Q) of over 4000 at a frequency of 6.4 GHz (third-order harmonic mode) using an optimized design and process. The biosensor shows excellent linear responses to target DNA in the range from 1 μg/ml to 1 ng/ml with a high sensitivity of 6.7 × 10(-16)g/cm(2)/Hz, hence the difference of a single hybridized DNA base can also be distinguished. With such a high mass resolution, the biosensor is capable of quantitative detection of living cancer cells. The frequency responses of single mouse mammary adenocarcinoma (EMT6) cell and mouse fibroblast (3T3) cell are studied. The interferences in the experiments show insignificant influence on the frequency shift, which verifies the high selectivity of the biosensor. The biosensor is also able to repeat the sensing ability after rough cleaning, therefore cost reduction is achieved from the recycling process in practical applications. The detection limit is defined from the noise analysis of the device, atomic resolution is realized according to the calculation, thereby initiating a potential tool for high-precision medical diagnoses and phenomena observation at the atomic-level. Copyright © 2015. Published by Elsevier B.V.
Ideal strength and ductility in metals from second- and third-order elastic constants
NASA Astrophysics Data System (ADS)
de Jong, Maarten; Winter, Ian; Chrzan, D. C.; Asta, Mark
2017-07-01
Under tensile loading the ideal strength of a solid is governed by mechanical instabilities corresponding to failure in tension or shear, indicative of intrinsically brittle or ductile behavior, respectively. Ideal-strength first-principles calculations are performed in this work on several hexagonal-close-packed (hcp) and body-centered-cubic (bcc) metals. It is shown that some metals fail in tension under uniaxial loading, whereas others fail in shear. The observed behavior is rationalized with a simple analytical model based on second-order and third-order elastic constants. This formalism correctly predicts the failure mode of all but one of the metals studied in this work and leads to fundamental insights into why some classes of metals are intrinsically brittle or ductile. Further, for the transition metals, filling of the d bands is shown to correlate with the type of mechanical instability encountered, thus providing insights into the effect of alloying on the intrinsic mechanical behavior of hcp and bcc metals.
Temperature dependence of third-order elastic constants of potassium manganese fluoride
NASA Astrophysics Data System (ADS)
Cao, Wenwu; Barsch, Gerhard R.; Jiang, Wenhua; Breazeale, Mack A.
1988-11-01
The nonlinearity parameters along the three principal symmetry directions have been measured for KMnF3 from 298 to 350 K by means of acoustic second-harmonic generation. In conjunction with our earlier data on the temperature dependence of the pressure derivatives of the elastic constants, the complete set of the six third-order elastic (TOE) constants has been determined in this temperature range. For c111, c123, and c166 the temperature dependence is linear, suggesting that the effect of the improper ferroelastic transition at 186 K is no longer present above 300 K. This permits us to eliminate the effects of zero-point and thermal motion and of the structural phase transition by linear extrapolation of the data to absolute zero temperature. The bare TOE constants thus obtained differ significantly from the room-temperature values. The bare (and the room-temperature) values exhibit large deviations from the Cauchy relations, indicating significant contributions from many-body forces.
Thangaraj, M; Ravi, G; Sabari Girisun, T C; Vinitha, G; Loganathan, A
2015-03-05
Single crystals of ethylenediaminium di(4-nitrophenolate) [EDA4NP] were grown by slow evaporation solution growth technique using ethanol as solvent at constant temperature. It crystallizes in monoclinic centrosymmetric space group C2/c with cell dimension a=11.326Ǻ, b=7.264Ǻ, c=20.036Ǻ; β=93.55°. Fourier Transform Infra Red (FT-IR) spectrum was recorded to identify various functional groups present in EDA4NP. Nuclear Magnetic Resonance (NMR) spectral studies were performed to confirm the functional groups. Thermogravimetric analysis and differential thermal analysis showed that the compound melts at 142.9°C. The material possesses a wide optical transparency window in the visible and near IR region (500-1200nm). The nonlinear refractive index, nonlinear absorption coefficient and third-order nonlinear susceptibility of EDA4NP were estimated to be n2=5.46×10(-8)cm(2)W(-1), β=0.65×10(-3)cmW(-1) and χ((3))=2.96×10(-6)esu respectively. The limiting behavior observed with the sample is attributed mainly to nonlinear refraction. Copyright © 2014 Elsevier B.V. All rights reserved.
Controlling the growth of porphyrin based nanostructures for tuning third-order NLO properties.
Wang, Liang; Chen, Yanli; Jiang, Jianzhuang
2014-01-01
A series of porphyrin nanospindles with controlled long axis length distributions of 330, 550, 800 nm, and 4 μm have been successfully fabricated via hierarchical self-assembly of cationic porphyrin (H₆TPyP)(4+) with the help of anionic surfactant sodium dodecyl sulfonate (SDS) due to the effective electrostatic interaction. These newly fabricated nanostructures are characterized by TEM and SEM techniques, powder X-ray diffraction analysis, electronic absorption spectroscopy, and confocal laser scanning microscopy (CLSM). The Z-scan technique with a laser duration of 5 ns at the wavelength of 532 nm reveals unreported size-dependent third-order NLO switching properties: the nonlinear absorption changes from saturation absorption to reversed saturation absorption and the nonlinear refraction from self-defocus to self-focus due to the change of the dominant scattering effect, from Rayleigh scattering for nanostructures with a smaller size than the wavelength of laser light, to Mie scattering for nanostructures with a larger size than the laser wavelength. This result is useful for the development of organic nanostructures with desired NLO properties, in particular the optical limiting properties.
Third-order nonlinear optical response in transparent solids using ultrashort laser pulses
NASA Astrophysics Data System (ADS)
Dota, K.; Dharmadhikari, J. A.; Mathur, D.; Dharmadhikari, A. K.
2012-06-01
The third-order optical nonlinearity, χ (3), is measured in transparent glasses (BK7 and fused silica) and crystals (BaF2 and quartz) using 36-fs, 800-nm laser pulses and the optical Kerr gate (OKE) technique; values are found to lie in the range 1.3-1.7×10-14 esu, in accordance with theoretical estimates. We probe the purely electronic response to the incident ultrashort laser pulse in fused silica and BK7 glass. In BaF2 and quartz, apart from the electronic response we also observe contribution from the nuclear response to the incident ultrashort pulses. We observe oscillatory modulations that persist for ˜400 fs. The response of the media (glasses and crystals) to ultrashort pulses is also measured using two-beam self-diffraction; the diffraction efficiency in the first-order grating is measured to be in the range of 0.06-0.13 %. Third harmonic generation due to self-phase matching in the transient grating geometry is measured as a function of temporal delay between the two incident ultrashort pulses, yielding the autocorrelation signal.
Exploiting multi-lead electrocardiogram correlations using robust third-order tensor decomposition.
Padhy, Sibasankar; Dandapat, Samarendra
2015-10-01
In this Letter, a robust third-order tensor decomposition of multi-lead electrocardiogram (MECG) comprising of 12-leads is proposed to reduce the dimension of the storage data. An order-3 tensor structure is employed to represent the MECG data by rearranging the MECG information in three dimensions. The three-dimensions of the formed tensor represent the number of leads, beats and samples of some fixed ECG duration. Dimension reduction of such an arrangement exploits correlations present among the successive beats (intra-beat and inter-beat) and across the leads (inter-lead). The higher-order singular value decomposition is used to decompose the tensor data. In addition, multiscale analysis has been added for effective care of ECG information. It grossly segments the ECG characteristic waves (P-wave, QRS-complex, ST-segment and T-wave etc.) into different sub-bands. In the meantime, it separates high-frequency noise components into lower-order sub-bands which helps in removing noise from the original data. For evaluation purposes, we have used the publicly available PTB diagnostic database. The proposed method outperforms the existing algorithms where compression ratio is under 10 for MECG data. Results show that the original MECG data volume can be reduced by more than 45 times with acceptable diagnostic distortion level.
Decoupling of the Dirac equation correct to the third order for the magnetic perturbation.
Ootani, Y; Maeda, H; Fukui, H
2007-08-28
A two-component relativistic theory accurately decoupling the positive and negative states of the Dirac Hamiltonian that includes magnetic perturbations is derived. The derived theory eliminates all of the odd terms originating from the nuclear attraction potential V and the first-order odd terms originating from the magnetic vector potential A, which connect the positive states to the negative states. The electronic energy obtained by the decoupling is correct to the third order with respect to A due to the (2n+1) rule. The decoupling is exact for the magnetic shielding calculation. However, the calculation of the diamagnetic property requires both the positive and negative states of the unperturbed (A=0) Hamiltonian. The derived theory is applied to the relativistic calculation of nuclear magnetic shielding tensors of HX (X=F,Cl,Br,I) systems at the Hartree-Fock level. The results indicate that such a substantially exact decoupling calculation well reproduces the four-component Dirac-Hartree-Fock results.
Bitrián, Vicente; Alcaraz, Olga; Trullàs, Joaquim
2009-06-21
The fluctuation-dissipation theorem for the static dielectric response function of systems of ions with inducible point dipoles is derived. It is shown that the static longitudinal dielectric function is determined by spatial correlations of both charge and dipole-moment density fluctuations. Moreover, it is deduced that the long-wavelength behavior of the charge structure factor for polarizable ion systems is different from that for systems of rigid ions. Molecular dynamics simulation results of rigid and polarizable ion models for molten AgI and NaI are reported.
NASA Astrophysics Data System (ADS)
Sit, P. H.-L.; Marzari, Nicola
2005-05-01
The static and dynamical properties of heavy water have been studied at ambient conditions with extensive Car-Parrinello molecular-dynamics simulations in the canonical ensemble, with temperatures ranging between 325 and 400K. Density-functional theory, paired with a modern exchange-correlation functional (Perdew-Burke-Ernzerhof), provides an excellent agreement for the structural properties and binding energy of the water monomer and dimer. On the other hand, the structural and dynamical properties of the bulk liquid show a clear enhancement of the local structure compared to experimental results; a distinctive transition to liquidlike diffusion occurs in the simulations only at the elevated temperature of 400K. Extensive runs of up to 50ps are needed to obtain well-converged thermal averages; the use of ultrasoft or norm-conserving pseudopotentials and the larger plane-wave sets associated with the latter choice had, as expected, only negligible effects on the final result. Finite-size effects in the liquid state are found to be mostly negligible for systems as small as 32molecules per unit cell.
Woon, D.E.; Dunning, T.H. Jr. )
1994-02-15
An accurate description of the electrical properties of atoms and molecules is critical for quantitative predictions of the nonlinear properties of molecules and of long-range atomic and molecular interactions between both neutral and charged species. We report a systematic study of the basis sets required to obtain accurate correlated values for the static dipole ([alpha][sub 1]), quadrupole ([alpha][sub 2]), and octopole ([alpha][sub 3]) polarizabilities and the hyperpolarizability ([gamma]) of the rare gas atoms He, Ne, and Ar. Several methods of correlation treatment were examined, including various orders of Moller--Plesset perturbation theory (MP2, MP3, MP4), coupled-cluster theory with and without perturbative treatment of triple excitations [CCSD, CCSD(T)], and singles and doubles configuration interaction (CISD). All of the basis sets considered here were constructed by adding even-tempered sets of diffuse functions to the correlation consistent basis sets of Dunning and co-workers. With multiply-augmented sets we find that the electrical properties of the rare gas atoms converge smoothly to values that are in excellent agreement with the available experimental data and/or previously computed results. As a further test of the basis sets presented here, the dipole polarizabilities of the F[sup [minus
Quasi-static multiaxial testing of PBX 9501: Creep effects on Estane molecular weight
Peterson, P.D.; Idar, D.J.; Rabie, R.; Fugard, C.S.; King, W.; Buntain, G.A.; Crane, N.B.
1999-02-01
High explosives (HE) can be subjected to low level loading due to weapon design. As with other materials, loads well below the elastic limit may still lead to material property changes over time. PBX 9501, a conventional high explosive, has been used in several system designs. To evaluate potential environmental aging effects on HE, it is necessary to characterize material-flow and mechanical-property changes occurring in PBX 9501. Low-level loads may bring about material changes if creep related phenomena, such as polymer disentanglement or uncrosslinking, occur in the material. Recently, several studies on HE have increased understanding of the effects of density and the relative percentage of constituents on materials properties, e.g. elastic modulus, ultimate strength, and strain at ultimate strength, at low strain rates ({approx} 10{sup {minus}3} to 10{sup {minus}1} s{sup {minus}1}). However, the authors are only beginning to understand the effects of quasi-static multiaxial loading on PBX 9501 and Estane molecular weight (MW) changes. The results of these experiments are presented in this report.
The third-order optical nonlinearities of Ge-Ga-Sb(In)-S chalcogenide glasses
Guo, Haitao; Chen, Hongyan; Hou, Chaoqi; Lin, Aoxiang; Zhu, Yonggang; Lu, Shoudi; Gu, Shaoxuan; Lu, Min; Peng, Bo
2011-05-15
Research highlights: {yields} It is firstly demonstrated that the nonlinear refractive index n{sub 2} is dependent on the covalency of bonds in chalcogenide glass. {yields} Homopolar metallic bonds in chalcogenide glass have positive contribution to large nonlinear refractive index n{sub 2} also. {yields} The 80GeS{sub 2}.20Sb{sub 2}S{sub 3} glass would be expected to be used in the all-optical switches working at 1330 nm and 1550 nm telecommunication wavelengths. -- Abstract: The third-order optical nonlinearities of 80GeS{sub 2}.(20 - x)Ga{sub 2}S{sub 3}.xY{sub 2}S{sub 3} (x = 0, 5, 10, 15, 20 and Y = Sb or In) chalcogenide glasses were investigated utilizing the Z-scan method at the wavelength of 800 nm and their linear optical properties and structure were also studied. By analyzing the compositional dependences and possible influencing factors including the linear refractive index, the concentration of lone electron pairs, the optical bandgap and the amount of weak covalent/homopolar bonds, it indicates that the electronic contribution in weak heteropolar covalent and homopolar metallic bonds is responsible for large nonlinear refractive index n{sub 2} in the chalcogenide glasses. These chalcogenide glasses have characteristics of environmentally friendship, wide transparency in the visible region, high nonlinear refractive index n{sub 2} and low nonlinear absorption coefficient {beta}, and would be expected to be used in the all-optical switches working at 1330 nm and 1550 nm telecommunication wavelengths.
Alternative formulation of explicitly correlated third-order Møller-Plesset perturbation theory
NASA Astrophysics Data System (ADS)
Ohnishi, Yu-ya; Ten-no, Seiichiro
2013-09-01
The second-order wave operator in the explicitly correlated wave function theory has been newly defined as an extension of the conventional s- and p-wave (SP) ansatz (also referred to as the FIXED amplitude ansatz) based on the linked-diagram theorem. The newly defined second-order wave operator has been applied to the calculation of the F12 correction to the third-order many-body perturbation (MP3) energy. In addition to this new wave operator, the F12 correction with the conventional first-order wave operator has been derived and calculated. Among three components of the MP3 correlation energy, the particle ladder contribution, which has shown the slowest convergence with respect to the basis set size, is fairly ameliorated by employing these F12 corrections. Both the newly defined and conventional formalisms of the F12 corrections exhibit a similar recovery of over 90% of the complete basis set limit of the particle ladder contribution of the MP3 correlation energy with a triple-zeta quality basis set for the neon atom, while the amount is about 75% without the F12 correction. The corrections to the ring term are small but the corrected energy has shown similar recovery as the particle ladder term. The hole ladder term has shown a rapid convergence even without the F12 corrections. Owing to these balanced recoveries, the deviation of the total MP3 correlation energy from the complete basis set limit has been calculated to be about 1 kcal/mol with the triple-zeta quality basis set, which is more than five times smaller than the error without the F12 correction.
An all-optical switch and third-order optical nonlinearity of 3,4-pyridinediamine
NASA Astrophysics Data System (ADS)
Badran, Hussain A.; Abul-Hail, Riyadh Ch.; Shaker, Hussain S.; musa, Abdulameer I.; Hassan, Qusay M. A.
2017-01-01
We investigated the third-order nonlinear optical properties of 3,4-pyridinediamine solution. The nonlinear measurements were taken by using single-beam Z-scan technique with cw laser at 473 nm. The effect of varying glucose concentration in a sample solution has been studied. The experimental results show that the nonlinear refractive index, n 2, and nonlinear absorption coefficient, β, are strongly dependent on the glucose concentration in a sample solution. The optical limiting properties are measured by a transmission technique. We find that the limiting threshold can be improved by a proper choice of glucose concentration in sample solution. A 3,4-pyridinediamine with 80 mmol glucose concentration showed a good switching property. This phenomenon was demonstrated by waveguiding a transistor-transistor logic modulated cw 473 nm laser beam as an excitation beam modulated at 10 Hz frequency collinearly with a continuous-wave SDL-635-100T laser beam of wavelength 653 nm through a quartz cuvette of thickness 1 mm. The results of pump-probe experiments show that the time of switch-on and switch-off of the 3,4-pyridinediamine was in μs for the pump intensity. The energy-dependent transmission studies also reveal better limiting property of the sample compound at nanosecond regime. Also, thermo-optic coefficients have been determined by thermal lens (TL) technique (-9.54 × 10-5 K-1) and it was found to be temperature dependent. This value was compared with result obtained by Z-scan calculations (-7.46 × 10-5 K-1). Thus, the nonlinear response of the material suggests that it has a potential application for high-sensitive photonic devices.
Molecular statics study of depth-dependent hysteresis in nano-scale adhesive elastic contacts
NASA Astrophysics Data System (ADS)
Deng, Weilin; Kesari, Haneesh
2017-07-01
The contact force—indentation-depth (P-h) measurements in adhesive contact experiments, such as atomic force microscopy, display hysteresis. In some cases, the amount of hysteretic energy loss is found to depend on the maximum indentation-depth. This depth-dependent hysteresis (DDH) is not explained by classical contact theories, such as Johnson-Kendall-Roberts and Derjaguin-Muller-Toporov, and is often attributed to surface moisture, material viscoelasticity, and plasticity. We present molecular statics simulations that are devoid of these mechanisms, yet still capture DDH. In our simulations, DDH is due to a series of surface mechanical instabilities. Surface features, such as depressions or protrusions, can temporarily arrest the growth or recession of the contact area. With a sufficiently large change of indentation-depth, the contact area grows or recedes abruptly by a finite amount and dissipates energy. This is similar to the pull-in and pull-off instabilities in classical contact theories, except that in this case the number of instabilities depends on the roughness of the contact surface. Larger maximum indentation-depths result in more surface features participating in the load-unload process, resulting in larger hysteretic energy losses. This mechanism is similar to the one recently proposed by one of the authors using a continuum mechanics-based model. However, that model predicts that the hysteretic energy loss always increases with roughness, whereas experimentally it is found that the hysteretic energy loss initially increases but then later decreases with roughness. Our simulations capture this non-monotonic dependence of hysteretic energy loss on roughness.
NASA Astrophysics Data System (ADS)
Jafari, A.; Naderali, R.; Motiei, H.
2017-02-01
The studies on the third-order nonlinear optical properties of carboxymethyl cellulose nanocomposite in the absence and presence of inorganic acid as a dopant was reported. The Z-scan technique was used to measure the nonlinear refraction n2, and absorption β, indexes and the third-order nonlinear susceptibility χ3. Characterization of this nanocomposite was performed by using scanning electron microscopy and Ultraviolet-Visible absorption spectroscopy in two different solvents; Dimethylformamide and N-Methylpyrrolidone. Additionally X-ray diffraction was used to study their crystal structure. The measured values of the nonlinear refraction of each sample in both of the solutions were in the order of 10-9m2/w and the corresponding third-order nonlinear susceptibilities were in the order 10-4 esu.
Johnson, Spencer J; Steer, Michael B
2014-10-01
A mathematical description of third-order scattered sound fields is derived using a multi-Gaussian beam (MGB) model that describes the sound field of any arbitrary axially symmetric beam as a series of Gaussian base functions. The third-order intermodulation (IM3) frequency components are produced by considering the cascaded nonlinear secondorder effects when analyzing the interaction between the firstand second-order frequency components during the nonlinear scattering of sound by sound from two noncollinear ultrasonic baffled piston sources. The theory is extended to the modeling of the sound beams generated by parametric transducer arrays, showing that the MGB model can be efficiently used to calculate both the second- and third-order sound fields of the array. Measurements are presented for the IM3 frequency components and parametric array sound fields and comparisons of the model are made with traditional simulation results from direct numerical integration.
NASA Astrophysics Data System (ADS)
Jin, Fangzhou; Liu, Ying; Geng, Jianpei; Huang, Pu; Ma, Wenchao; Shi, Mingjun; Duan, Chang-Kui; Shi, Fazhan; Rong, Xing; Du, Jiangfeng
2017-01-01
As a fundamental postulate of quantum mechanics, Born's rule assigns probabilities to the measurement outcomes of quantum systems and excludes multiorder quantum interference. Here we report an experiment on a single spin in diamond to test Born's rule by inspecting the third-order quantum interference. The ratio of the third-order quantum interference to the second order in our experiment is bounded to the scale of 1 ×10-3 , which provides a stringent constraint on the potential breakdown of Born's rule.
Huang, Zhipeng; Wang, Ruxue; Jia, Ding; Maoying, Li; Humphrey, Mark G; Zhang, Chi
2012-03-01
A facile method for the low-cost and large-scale production of silicon nanowires has been developed. Silicon powders were subjected to sequential metal plating and metal-assisted chemical etching, resulting in well-defined silicon nanowires. The morphology and structure of the silicon nanowires were investigated, revealing that single-crystal silicon nanowires with average diameters of 79 ± 35 nm and length more than 10 μm can be fabricated. The silicon nanowires show excellent third-order nonlinear optical properties, with a third-order susceptibility much larger than that of bulk silicon, porous silicon, and silicon nanocrystals embedded in SiO(2).
Third order nonlinear optical response exhibited by mono- and few-layers of WS_{2}
Torres-Torres, Carlos; Perea-López, Néstor; Elías, Ana Laura; Gutiérrez, Humberto R.; Cullen, David A.; Berkdemir, Ayse; López-Urías, Florentino; Terrones, Humberto; Terrones, Mauricio
2016-04-13
In this work, strong third order nonlinear optical properties exhibited by WS_{2} layers are presented. Optical Kerr effect was identified as the dominant physical mechanism responsible for these third order optical nonlinearities. An extraordinary nonlinear refractive index together with an important contribution of a saturated absorptive response was observed to depend on the atomic layer stacking. Comparative experiments performed in mono- and few-layer samples of WS_{2} revealed that this material is potentially capable of modulating nonlinear optical processes by selective near resonant induced birefringence. In conclusion, we envision applications for developing all-optical bidimensional nonlinear optical devices.
Third-order aberrations in GRIN crystalline lens: A new method based on axial and field rays
Río, Arturo Díaz del; Gómez-Reino, Carlos; Flores-Arias, M. Teresa
2014-01-01
This paper presents a new procedure for calculating the third-order aberration of gradient-index (GRIN) lenses that combines an iterative numerical method with the Hamiltonian theory of aberrations in terms of two paraxial rays with boundary conditions on general curved end surfaces and, as a second algebraic step has been presented. Application of this new method to a GRIN human is analyzed in the framework of the bi-elliptical model. The different third-order aberrations are determined, except those that need for their calculation skew rays, because the study is made only for meridional rays. PMID:25444647
NASA Astrophysics Data System (ADS)
Kumar, Anuj; Yadav, Mahesh Pal Singh
2017-07-01
We have reported a theoretical investigation on nonlinear optical behaviour, electronic and optical properties and other molecular properties of the organic nonlinear optical crystal 2-aminopyridinium p-toluenesulphonate (APPTS). The computation has been done using density functional theory (DFT) method employing 6-31G(d) basis set and Becke's three-parameter hybrid functional (B3LYP). Calculated values of static hyperpolarizability confirm the good nonlinear behaviour of the molecule. Electronic behaviour and global reactivity descriptor parameters are calculated and analysed using HOMO-LUMO analysis. Energy band gap and simulated UV-visible spectrum show good agreement with experimental results. Other important molecular properties like rotational constant, zero-point vibrational energy, total energy at room temperature and pressure have also been calculated in the ground state.
Slovin, Mitchell R; Shirts, Michael R
2015-07-28
We quantify some of the effects of patterned nanoscale surface texture on static contact angles, dynamic contact angles, and dynamic contact angle hysteresis using molecular dynamics simulations of a moving Lennard-Jones droplet in contact with a solid surface. We observe static contact angles that change with the introduction of surface texture in a manner consistent with theoretical and experimental expectations. However, we find that the introduction of nanoscale surface texture at the length scale of 5-10 times the fluid particle size does not affect dynamic contact angle hysteresis even though it changes both the advancing and receding contact angles significantly. This result differs significantly from microscale experimental results where dynamic contact angle hysteresis decreases with the addition of surface texture due to an increase in the receding contact angle. Instead, we find that molecular-kinetic theory, previously applied only to nonpatterned surfaces, accurately describes dynamic contact angle and dynamic contact angle hysteresis behavior as a function of terminal fluid velocity. Therefore, at length scales of tens of nanometers, the kinetic phenomena such as contact line pinning observed at larger scales become insignificant in comparison to the effects of molecular fluctuations for moving droplets, even though the static properties are essentially scale-invariant. These findings may have implications for the design of highly hierarchical structures with particular wetting properties. We also find that quantitatively determining the trends observed in this article requires the careful selection of system and analysis parameters in order to achieve sufficient accuracy and precision in calculated contact angles. Therefore, we provide a detailed description of our two-surface, circular-fit approach to calculating static and dynamic contact angles on surfaces with nanoscale texturing.
Nishimoto, Yoshio
2015-09-07
We develop a formalism for the calculation of excitation energies and excited state gradients for the self-consistent-charge density-functional tight-binding method with the third-order contributions of a Taylor series of the density functional theory energy with respect to the fluctuation of electron density (time-dependent density-functional tight-binding (TD-DFTB3)). The formulation of the excitation energy is based on the existing time-dependent density functional theory and the older TD-DFTB2 formulae. The analytical gradient is computed by solving Z-vector equations, and it requires one to calculate the third-order derivative of the total energy with respect to density matrix elements due to the inclusion of the third-order contributions. The comparison of adiabatic excitation energies for selected small and medium-size molecules using the TD-DFTB2 and TD-DFTB3 methods shows that the inclusion of the third-order contributions does not affect excitation energies significantly. A different set of parameters, which are optimized for DFTB3, slightly improves the prediction of adiabatic excitation energies statistically. The application of TD-DFTB for the prediction of absorption and fluorescence energies of cresyl violet demonstrates that TD-DFTB3 reproduced the experimental fluorescence energy quite well.
NASA Astrophysics Data System (ADS)
Pan, Liang; Xu, Kun
2016-08-01
In this paper, for the first time a third-order compact gas-kinetic scheme is proposed on unstructured meshes for the compressible viscous flow computations. The possibility to design such a third-order compact scheme is due to the high-order gas evolution model, where a time-dependent gas distribution function at cell interface not only provides the fluxes across a cell interface, but also presents a time accurate solution for flow variables at cell interface. As a result, both cell averaged and cell interface flow variables can be used for the initial data reconstruction at the beginning of next time step. A weighted least-square procedure has been used for the initial reconstruction. Therefore, a compact third-order gas-kinetic scheme with the involvement of neighboring cells only can be developed on unstructured meshes. In comparison with other conventional high-order schemes, the current method avoids the Gaussian point integration for numerical fluxes along a cell interface and the multi-stage Runge-Kutta method for temporal accuracy. The third-order compact scheme is numerically stable under CFL condition CFL ≈ 0.5. Due to its multidimensional gas-kinetic formulation and the coupling of inviscid and viscous terms, even with unstructured meshes, the boundary layer solution and vortex structure can be accurately captured by the current scheme. At the same time, the compact scheme can capture strong shocks as well.
Zhaoyang Li; Yuxin Leng; Daxing Rao; Lei Chen; Yaping Dai
2015-10-31
A method is proposed for third-order dispersion compensation in compressors of femtosecond petawatt laser facilities employing object-image-grating self-tiling technology to prevent the return of the laser beam in amplifying chains. Simulations are performed for functioning and being developed Nd : glass and Ti : sapphire petawatt-level lasers. (control of radiation parameters)
NASA Technical Reports Server (NTRS)
Brown, C. M., Jr.; Monopoli, R. V.
1974-01-01
A linear system identification technique developed by Lion is adapted for use on a third-order system with six unknown parameters and noisy input-output measurements. A digital computer is employed so that rapid identification takes place with only two state variable filters. Bias in the parameter estimates is partially eliminated by a signal-to-noise ratio testing procedure.
Augustine Muwamba; Devendra M. Amatya; Carl C. Trettin; James B. Glover
2016-01-01
Monitoring of stream water chemistry in forested watersheds provides information to environmental scientists that relate management operations to hydrologic and biogeochemical processes. We used data for the first order watershed, WS80, and second order watershed, WS79, at Santee Experimental Forest. We also used data from a third order watershed, WS78, to...
A Kramers-Moyal Approach to the Analysis of Third-Order Noise with Applications in Option Valuation
Popescu, Dan M.; Lipan, Ovidiu
2015-01-01
We propose the use of the Kramers-Moyal expansion in the analysis of third-order noise. In particular, we show how the approach can be applied in the theoretical study of option valuation. Despite Pawula’s theorem, which states that a truncated model may exhibit poor statistical properties, we show that for a third-order Kramers-Moyal truncation model of an option’s and its underlier’s price, important properties emerge: (i) the option price can be written in a closed analytical form that involves the Airy function, (ii) the price is a positive function for positive skewness in the distribution, (iii) for negative skewness, the price becomes negative only for price values that are close to zero. Moreover, using third-order noise in option valuation reveals additional properties: (iv) the inconsistencies between two popular option pricing approaches (using a “delta-hedged” portfolio and using an option replicating portfolio) that are otherwise equivalent up to the second moment, (v) the ability to develop a measure R of how accurately an option can be replicated by a mixture of the underlying stocks and cash, (vi) further limitations of second-order models revealed by introducing third-order noise. PMID:25625856
Corona, María; Garay-Palmett, Karina; U'Ren, Alfred B
2011-01-15
We present an experimental proposal for the generation of photon triplets based on third-order spontaneous parametric downconversion in thin optical fibers. Our analysis includes expressions for the quantum state, which describes the photon triplets and for the generation rate in terms of all experimental parameters. We also present, for a specific source design, numerically calculated generation rates.
Third-order particle-hole ring diagrams with contact-interactions and one-pion exchange
NASA Astrophysics Data System (ADS)
Kaiser, N.
2017-05-01
The third-order particle-hole ring diagrams are evaluated for a NN-contact interaction of the Skyrme type. The pertinent four-loop coefficients in the energy per particle \\bar{E}(kf) ˜ kf^{5+2n} are reduced to double integrals over cubic expressions in Euclidean polarization functions. Dimensional regularization of divergent integrals is performed by subtracting power divergences and the validity of this method is checked against the known analytical results at second order. The complete \\mathcal{O}(p2) NN-contact interaction is obtained by adding two tensor terms and their third-order ring contributions are also calculated in detail. The third-order ring energy arising from long-range 1π -exchange is computed and it is found that direct and exchange contributions are all attractive. The very large size of the three-ring energy due to point-like 1π-exchange, \\bar{E}(k_{f0}) ˜eq -92 MeV at saturation density, is however in no way representative for that of realistic chiral NN-potentials. Moreover, the third-order (particle-particle and hole-hole) ladder diagrams are evaluated with the full \\mathcal{O}(p2) contact interaction, and the simplest three-ring contributions to the isospin-asymmetry energy A(kf)˜ kf5 are studied.
Geskin, Victor M; Lambert, Christoph; Brédas, Jean-Luc
2003-12-17
We present a quantum-chemical analysis of the molecular structure and second- and third-order polarizabilities in a series of promising nonlinear optical (NLO) chromophores, the zwitterionic ammonio/borato diphenylpolyenes, R3N+Ph(C=C)nPhB-R3, whose synthesis has been reported recently. The molecular geometries are obtained via MP2/6-31G optimization, while the NLO properties are calculated with the INDO Hamiltonian using the sum-over-states and finite-field real-space methods. The real-space approach allows the direct evaluation of the NLO-active segments of the molecules, while the sum-over-states results illustrate the virtual excitations and charge-transfer pathways that are essential in the NLO response. Both methods highlight the remarkable and unexpected result that it is the strongly polarized phenylene groups that play the key role in generating a high NLO response.
Valverde, Clodoaldo; Rodrigues, Rosemberg F N; Machado, Daniel F S; Baseia, Basílio; de Oliveira, Heibbe C B
2017-04-01
A supermolecular approach combined with an iterative electrostatic scheme was employed to investigate the nonlinear optical properties of the hybrid L-arginine phosphate monohydrate crystal, the procedure being aided by DFT calculations. The supermolecular scheme basically treated the molecules surrounding the unit cell as point charges; this approximation results in rapid convergence, making it a feasible method. DFT functionals of different flavors were considered: B3LYP, B2PLYP, CAM-B3LYP, ωB97, and M06HF, utilizing the 6-311 + G(d) basis set. All functionals gave sufficiently accurate values for the dipole moment (μ) with respect to the experimental value 32(2) D. For the average linear polarizability ([Formula: see text]) and the total first hyperpolarizability (β tot), good agreement was observed between the DFT-calculated values and MP2-derived results reported in the literature. For the second hyperpolarizability, both static and dynamic regimes were considered. The point-charge embedding approach led to an attenuation of the second hyperpolarizability γ for all frequencies considered. Excitations of γ were not observed for frequencies smaller than 0.1 a.u. For the second hyperpolarizability (both static and dynamic), computational results showed that L-arginine phosphate monohydrate exhibits a large nonlinear optical effect, which implies the occurrence of microscopic third-order NLO behavior.
NASA Astrophysics Data System (ADS)
Birge, Robert R.; Masthay, M. B.; Stuart, Jeffrey A.; Tallent, Jack R.; Zhang, Chian-Fan
1991-06-01
The third-order (pi) -electron polarizability, (gamma) (pi), of bacteriorhodopsin in the 0.0 - 1.2 eV optical region is assigned based on an analysis of the experimental two-photon properties of the low-lying singlet state manifold. The following selected values of (gamma) (pi) (units of 10-36 esu) are observed: (gamma) (0;0,0,0) equals 2482 +/- 327; (gamma) (-3(omega) ;(omega) ,(omega) ,(omega) ) equals 2976 +/- 385 ((omega) equals 0.25 eV), 5867 +/- 704 ((omega) = 0.5 eV), 14863 +/- 1614 ((omega) = 0.66 eV), 15817 +/- 2314 ((omega) equals 1.0 eV), 10755 +/- 1733 ((omega) equals 1.17 eV). The third-order polarizability of this protein which contains an all-trans retinyl protonated Schiff base chromophore with six double bonds, is comparable to that observed for much longer chain polyenes (for example, dodecapreno (beta) -carotene, a polyene with 19 double bonds, exhibits a third-order (pi) -electron polarizability at 0.66 eV of 17000 +/- 6000 X 10-36 esu. The authors attribute the enhanced third-order nonlinearity associated with the protein bound chromophore of bacteriorhodopsin to two mutually enhancing origins. First, the chromophore is protonated, and the resultant charge reorganization enhances the polarizability in a fashion that is similar to that known to occur for polaronic and bipolaronic chromophores. It is estimated that protonation generates a five-fold enhancement in (gamma) (pi). Second, the protein bound chromophore exhibits a large change in dipole moment upon excitation into the lowest-lying, strongly-allowed 1B*u+-like state ((Delta) (mu) = 13.5 D). The latter property is responsible for a Type III enhancement of the third-order polarizability, and yields at least a 20-fold increase in (gamma) (pi).
Chen, L.X.; Laible, P.D.; Spano, F.C.; Manas, E.S.
1997-09-01
Enhancement of the nonresonant second order molecular hyperpolarizabilities {gamma} were observed in stacked macrocyclic molecular systems, previously in a {micro}-oxo silicon phthalocyanine (SiPcO) monomer, dimer and trimer series, and now in bacteriochlorophyll a (BChla) arrays of light harvesting (LH) proteins. Compared to monomeric BChla in a tetrahydrofuran (THF) solution, the <{gamma}> for each macrocycle was enhanced in naturally occurring stacked macrocyclic molecular systems in the bacterial photosynthetic LH proteins where BChla`s are arranged in tilted face-to-face arrays. In addition, the {gamma} enhancement is more significant in B875 of LH1 than in B850 in LH2. Theoretical modeling of the nonresonant {gamma} enhancement using simplified molecular orbitals for model SiPcO indicated that the energy level of the two photon state is crucial to the {gamma} enhancement when a two photon process is involved, whereas the charge transfer between the monomers is largely responsible when one photon near resonant process is involved. The calculated results can be extended to {gamma} enhancement in B875 and B850 arrays, suggesting that BChla in B875 are more strongly coupled than in B850. In addition, a 50--160 fold increase in <{gamma}> for the S{sub 1} excited state of relative to S{sub 0} of bacteriochlorophyll in vivo was observed which provides an alternative method for probing excited state dynamics and a potential application for molecular switching.
NASA Astrophysics Data System (ADS)
Jayakrishnan, K.; Joseph, Antony; Mathew, K. Paulson; Siji, T. B.; Chandrasekharan, K.; Narendran, N. K. Siji; Jaseela, M. A.; Muraleedharan, K.
2016-08-01
The third order nonlinear optical features of certain novel thiocoumarin derivatives have been studied. Single beam Z-scan study on these compounds reveals that the compounds exhibit self defocusing effect upon irradiation with 532 nm, 7 ns pulses of Nd:YAG laser. Nonlinear absorption coefficient, nonlinear refractive index and second-order molecular hyperpolarizability values were estimated. The optical power limiting properties of the compounds are found to be attributable to both two-photon and excited state absorption. Some of the samples show nonlinear absorption coefficient (βeff) as high as 24.5 cm/GW. UV-Visible and photoluminescence outputs of these compounds reveal remarkable absorptive and emissive properties. This article also reports extraordinary growth of third order optical nonlinearity in pure coumarin upon certain donor substitutions in lieu of hydrogen. Degenerate Four Wave Mixing (DFWM) signals of the compounds were analyzed to verify the Z-scan results. Electrostatic Surface Potential (ESP) mapping and structure optimization techniques have been employed to interpret the structure-property relationship of each molecule.
NASA Astrophysics Data System (ADS)
Sivanandan, T.; Kalainathan, S.
2015-04-01
The third order nonlinear optical properties of Monothiourea-cadmium Sulphate Dihydrate crystal were measured using a He-Ne laser (λ=632.8 nm) by a Z-scan technique. The magnitude of nonlinear refractive index (n2) and nonlinear absorption coefficient was found to be 4.4769×10-11 m2/W and 1.233×10-2 m/W respectively. The third order non-linear optical susceptibility χ(3) was found to be in the order of 3.6533×10-2 esu. The negative sign of non-linear refractive index shows the self-defocusing nature of the gel grown crystal. The second-order molecular hyperpolarizability γ of the grown crystal is 1.2822×10-33 esu. Laser damage threshold was measured by using an Nd: YAG laser (1064 nm). Photoconductivity studies of the gel grown crystal revealed that the crystal possesses positive photoconducting nature. The results obtained from Z-scan, laser damage threshold and photoconducting studies reveal that the crystal can be a possible candidate material for photonics device, optical switches, and optical power limiting application.
2014-09-01
Development of a Robust Static Punch Experiment for Screening Unprocessed Ultra-High Molecular Weight Polyethylene (UHMWPE) Unidirectional...Screening Unprocessed Ultra-High Molecular Weight Polyethylene (UHMWPE) Unidirectional Cross-Ply Material David Gray, Robert Kaste, and Paul...Unprocessed Ultra-High Molecular Weight Polyethylene (UHMWPE) Unidirectional Cross-Ply Material 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM
NASA Astrophysics Data System (ADS)
English, Niall J.; Garate, José-A.
2016-08-01
An extensive suite of non-equilibrium molecular-dynamics simulation has been performed for ˜0.85-0.9 μs of human aquaporin 4 in the absence and presence of externally applied static and alternating electric fields applied along the channels (in both axial directions in the static case, taken as the laboratory z-axis). These external fields were of 0.0065 V/Å (r.m.s.) intensity (of the same order as physiological electrical potentials); alternating fields ranged in frequency from 2.45 to 500 GHz. In-pore gating dynamics was studied, particularly of the relative propensities for "open" and "closed" states of the conserved arginines in the arginine/aromatic area (itself governed in no small part by external-field response of the dipolar alignment of the histidine-201 residue in the selectivity filter). In such a manner, the intimate connection of field-response governing "two-state" histidine states was established statistically and mechanistically. Given the appreciable size of the energy barriers for histidine-201 alignment, we have also performed non-equilibrium metadynamics/local-elevation of static fields applied along both directions to construct the free-energy landscape thereof in terms of external-field direction, elucidating the importance of field direction on energetics. We conclude from direct measurement of deterministic molecular dynamics in conjunction with applied-field metadynamics that the intrinsic electric field within the channel points along the +z-axis, such that externally applied static fields in this direction serve to "open" the channel in the selectivity-filter and the asparagine-proline-alanine region.
English, Niall J; Garate, José-A
2016-08-28
An extensive suite of non-equilibrium molecular-dynamics simulation has been performed for ∼0.85-0.9 μs of human aquaporin 4 in the absence and presence of externally applied static and alternating electric fields applied along the channels (in both axial directions in the static case, taken as the laboratory z-axis). These external fields were of 0.0065 V/Å (r.m.s.) intensity (of the same order as physiological electrical potentials); alternating fields ranged in frequency from 2.45 to 500 GHz. In-pore gating dynamics was studied, particularly of the relative propensities for "open" and "closed" states of the conserved arginines in the arginine/aromatic area (itself governed in no small part by external-field response of the dipolar alignment of the histidine-201 residue in the selectivity filter). In such a manner, the intimate connection of field-response governing "two-state" histidine states was established statistically and mechanistically. Given the appreciable size of the energy barriers for histidine-201 alignment, we have also performed non-equilibrium metadynamics/local-elevation of static fields applied along both directions to construct the free-energy landscape thereof in terms of external-field direction, elucidating the importance of field direction on energetics. We conclude from direct measurement of deterministic molecular dynamics in conjunction with applied-field metadynamics that the intrinsic electric field within the channel points along the +z-axis, such that externally applied static fields in this direction serve to "open" the channel in the selectivity-filter and the asparagine-proline-alanine region.
Chen, Yuxiang; Cao, Wei; Wang, Chiming; Qi, Dongdong; Wang, Kang; Jiang, Jianzhuang
2016-03-21
2(3),9(10),16(17),23(24)-Tetrakis(dibutylamino)phthalocyanine compounds M{Pc[N(C4H9)2]4} (1-5; M = 2H, Mg, Ni, Cu, Zn) were prepared and characterized by a range of spectroscopic methods in addition to elemental analysis. Electrochemical and electronic absorption spectroscopic studies revealed the more effective conjugation of the nitrogen lone pair of electrons in the dibutylamino side chains with the central phthalocyanine π system in M{Pc[N(C4H9)2]4} than in M{Pc[N(C4H9)2]8}, which, in turn, results in superior third-order nonlinear-optical (NLO) properties of H2{Pc[N(C4H9)2]4} (1) over H2{Pc[N(C4H9)2]8}, as revealed by the obviously larger effective imaginary third-order molecular hyperpolarizability (Im{χ((3))}) of 6.5 × 10(-11) esu for the former species than for the latter one with a value of 3.4 × 10(-11) esu. This is well rationalized on the basis of both structural and theoretical calculation results. The present result seems to represent the first effort toward directly connecting the peripheral functional substituents, electronic structures, and NLO functionality together for phthalocyanine molecular materials, which will be helpful for the development of functional phthalocyanine materials via molecular design and synthesis even through only tuning of the peripheral functional groups.
Rodríguez-Santiago, Luis; Alí-Torres, Jorge; Vidossich, Pietro; Sodupe, Mariona
2015-05-28
Several lines of evidence supporting the role of metal ions in amyloid aggregation, one of the hallmarks of Alzheimer's disease (AD), have turned metal ion chelation into a promising therapeutic treatment. The design of efficient chelating ligands requires proper knowledge of the electronic and molecular structure of the complexes formed, including their hydration properties. Among various potential chelators, clioquinol (5-chloro-7-iodo-8-hydroxyquinoline, CQH) has been evaluated with relative success in in vitro experiments and even in phase 2 clinical trials. Clioquinol interacts with Zn(ii) to lead to a binary metal/ligand 1 : 2 stoichiometric complex in which the phenolic group of CQH is deprotonated, resulting in Zn(CQ)2 neutral complexes, to which additional water molecules may coordinate. In the present work, the coordinative properties of clioquinol in aqueous solution have been analyzed by means of static, minimal cluster based DFT calculations and explicit solvent ab initio molecular dynamics simulations. Results from static calculations accounting for solvent effects by means of polarized continuum models suggest that the preferred metal coordination environment is tetrahedral Zn(CQ)2, whereas ab initio molecular dynamics simulations point to quasi degenerate penta Zn(CQ)2(H2O) and hexa Zn(CQ)2(H2O)2 coordinated complexes. The possible reasons for these discrepant results are discussed.
NASA Astrophysics Data System (ADS)
Koura, Akihide; Shimojo, Fuyuki
2017-08-01
We have investigated the pressure dependence of the static structure of liquid GeTe based on ab initio molecular dynamics simulations. The pressure range is between ambient pressure and 250 GPa, and their temperatures between 1000 K and 4000 K, which keep the liquid state. In this study, we found two transition stages caused by the compression. At the first stage, below 12 GPa, atomic distances elongate and Peierls-type distortion is dissolved with increasing pressure. At the second stage, above 12 GPa, atomic distances shorten and the electronic states shows metallic.
NASA Astrophysics Data System (ADS)
Mulenko, S. A.; Rudenko, V. I.; Liakhovetskyi, V. R.; Brodin, A. M.; Stefan, N.
2016-10-01
We report on a study of the third-order nonlinear optical properties of Fe2O3 thin films, grown by the method of laser deposition on silica (SiO2) substrates. The films were synthesized on substrates at different temperatures (293 K and 800 K) and under different oxygen pressures (0.1 Pa, 0.5 Pa, 1.0 Pa). The resulting films were amorphous, if grown on cold substrates (293 K), or polycrystalline otherwise. The third-order optical susceptibility χ(3) of the films was determined by the Z-scan method at the wavelengths of 1064 nm and 532 nm and the laser pulse width of 20 ns. Remarkably high χ(3) values on the order of 10-4 esu at 1064 nm are obtained. The results show that Fe2O3 thin films are promising nonlinear materials for contemporary optoelectronics.
NASA Astrophysics Data System (ADS)
Sugimoto, Noriaki; Koiwai, Akihiko; Hyodo, Shi-aki; Hioki, Tatsumi; Noda, Shoji
1995-02-01
Nonresonant third-order harmonic generation from CdS clusters encapsulated in zeolite A and X was observed at a fundamental wavelength of 1900 nm. To avoid scattering from the surfaces of the small zeolite crystals, the powder samples were dispersed in a liquid with nearly the same refractive index as that of the samples. The third-order optical susceptibilities of CdS-encapsulated zeolite A and X estimated from the intensity of their Maker fringe patterns were 4.1×10-12 and 1.1×10-11 esu, respectively. These values were slightly smaller than those reported for the 1.5 nm surface-capped CdS cluster. The hyperpolarizabilities of CdS clusters encapsulated in zeolite A and X were estimated by assuming the Lorentz local field to be in the range of 380-480×10-36 and 270-390×10-36 esu, respectively.
Alcocer-Sosa, Mauricio; Gutiérrez, David
2017-04-01
We present a forward modeling solution in the form of an array response kernel for magnetoencephalography. We consider the case when the brain's anatomy is approximated by an ellipsoid and an equivalent current dipole model is used to approximate brain sources. The proposed solution includes the contributions up to the third-order ellipsoidal harmonic terms; hence, we compare this new approximation against the previously available one that only considered up to second-order harmonics. We evaluated the proposed solution when used in the inverse problem of estimating physiologically feasible visual evoked responses from magnetoencephalography data. Our results showed that the contribution of the third-order harmonic terms provides a more realistic representation of the magnetic fields (closer to those generated with a numerical approximation based on the boundary element method) and, subsecuently, the estimated equivalent current dipoles are a better fit to those observed in practice (e.g., in visual evoked potentials). Copyright © 2016 John Wiley & Sons, Ltd.
Third-order aberrations in GRIN crystalline lens: a new method based on axial and field rays.
Río, Arturo Díaz Del; Gómez-Reino, Carlos; Flores-Arias, M Teresa
2015-01-01
This paper presents a new procedure for calculating the third-order aberration of gradient-index (GRIN) lenses that combines an iterative numerical method with the Hamiltonian theory of aberrations in terms of two paraxial rays with boundary conditions on general curved end surfaces and, as a second algebraic step has been presented. Application of this new method to a GRIN human is analyzed in the framework of the bi-elliptical model. The different third-order aberrations are determined, except those that need for their calculation skew rays, because the study is made only for meridional rays. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.
NASA Astrophysics Data System (ADS)
Ren, Jun; Zheng, Xiaorui; Tian, Zhiming; Li, Dan; Wang, Pu; Jia, Baohua
2016-11-01
Giant third-order nonlinear absorption and refraction of electrochemical graphene oxide (EGO) film were investigated in the femtosecond regime using the single beam Z-scan technique. The excellent chemical stability of the EGO film under high-power illumination up to 400 mJ/cm2 is demonstrated, which can be attributed to the low oxidation degree revealed by the optical and Raman spectroscopies. High and broadband linear transmission over 70% has been observed from the visible to the infrared range. The low-loss EGO film with giant third-order nonlinearity, excellent chemical stability, large-scale preparation and flexible integration has a great potential for high-power nonlinear optical applications.
2010-01-01
Although taurine and glutamate are the most abundant amino acids conducting neural signals in the central nervous system, the communication between these two neurotransmitters is largely unknown. This study explores the interaction of taurine and glutamate in the retinal third-order neurons. Using specific antibodies, both taurine and taurine transporters were localized in photoreceptors and Off-bipolar cells, glutamatergic neurons in retinas. It is possible that Off-bipolar cells release juxtaposed glutamate and taurine to activate the third-order neurons in retina. The interaction of taurine and glutamate was studied in acutely dissociated third-order neurons in whole-cell patch-clamp recording and Ca2+ imaging. We find that taurine effectively reduces glutamate-induced Ca2+ influx via ionotropic glutamate receptors and voltage-dependent Ca2+ channels in the neurons, and the effect of taurine was selectively inhibited by strychnine and picrotoxin, but not GABA receptor antagonists, although GABA receptors are present in the neurons. A CaMKII inhibitor partially reversed the effect of taurine, suggesting that a Ca2+/calmodulin-dependent pathway is involved in taurine regulation. On the other hand, a rapid influx of Ca2+ through ionotropic glutamate receptors could inhibit the amplitude and kinetics of taurine-elicited currents in the third-order neurons, which could be controlled with intracellular application of BAPTA a fast Ca2+ chelator. This study indicates that taurine is a potential neuromodulator in glutamate transmission. The reciprocal inhibition between taurine and glutamate in the postsynaptic neurons contributes to computation of visual signals in the retinal neurons. PMID:20804625
NASA Astrophysics Data System (ADS)
Semenova, I. V.; Belashov, A. V.; Garbuzov, F. E.; Samsonov, A. M.; Semenov, A. A.
2017-06-01
We demonstrate an alternative approach to determination of the third order elastic moduli of materials based on registration of nonlinear bulk strain waves in three basic structural waveguides (rod, plate and shell) and further calculation of the Murnaghan moduli from the recorded wave parameters via simple algebra. These elastic moduli are available in literature for a limited number of materials and are measured with considerable errors, that evidences a demand in novel approaches to their determination.
Weerasekara, Gihan; Tokunaga, Akihiro; Terauchi, Hiroki; Eberhard, Marc; Maruta, Akihiro
2015-01-12
One of the extraordinary aspects of nonlinear wave evolution which has been observed as the spontaneous occurrence of astonishing and statistically extraordinary amplitude wave is called rogue wave. We show that the eigenvalues of the associated equation of nonlinear Schrödinger equation are almost constant in the vicinity of rogue wave and we validate that optical rogue waves are formed by the collision between quasi-solitons in anomalous dispersion fiber exhibiting weak third order dispersion.
NASA Astrophysics Data System (ADS)
Beshtokov, M. Kh.
2014-09-01
A nonlocal boundary value problem for a third-order hyperbolic equation with variable coefficients is considered in the one- and multidimensional cases. A priori estimates for the nonlocal problem are obtained in the differential and difference formulations. The estimates imply the stability of the solution with respect to the initial data and the right-hand side on a layer and the convergence of the difference solution to the solution of the differential problem.
NASA Astrophysics Data System (ADS)
Huang, Wentao; Wang, Shufeng; Yang, Hong; Gong, Qihuang; Zhan, Xiaowei; Liu, Yunqi; Zhu, Daoben
2001-12-01
A femtosecond time-resolved optical Kerr gate method, using 115 fs laser pulses at 830 nm, has been applied to investigate the third-order nonlinearity of two novel copolymers containing fluorene and tetraphenyldiaminobiphenyl units in their backbones. Ultrafast off-resonant optical Kerr responses have been observed and the magnitude of the second-order hyperpolarizability was measured as large as 10 -30 esu. The origin of the extraordinary large value was explored and compared to other organic materials.
1991-02-01
AD-A235 622 WL-TR-91-4015 THE SYNTHESIS AND EVALUATION OF THIRD-ORDER OPTICAL NONLINEARITIES OF MODEL COMPOUNDS CONTAINING BENZOTHIAZOLE ...Nonlinearities of Model Compounds Containing Benzothiazole , Benzimidazole, and Benzoxazole Moieties 12 PERSONAL AUTHOR(S) Bruce A. Reinhardt, Marilyn R...necessary and identify by block number) FIELD GROUP SUB-GROUP nonlinear optical properties benzothiazole u/ 03 degenerate four-wave mixing benzimidazole 21
Single-beam Z-scan measurement of the third-order optical nonlinearities of azo dyes.
Gayathri, C; Ramalingam, A
2007-11-01
Organic dyes are very attractive optical materials for photonics and biophotonic applications. To quantitatively characterize their third-order nonlinear coefficients we have performed the experiments on two different azo dyes using a diode-pumped Nd:YAG laser at 532 nm. The |chi(3)| is of the order of 10(-6) esu. The relative contributions from nonlinear absorption (NLA) and nonlinear refraction (NLR) are dependent on the chemical structure and linear absorption of the dyes.
Linear and third-order nonlinear optical responses of multilayered Ag:Si3N4 nanocomposites.
Toudert, J; Fernandez, H; Babonneau, D; Camelio, S; Girardeau, T; Solis, J
2009-11-25
The linear and third-order nonlinear responses of tailored Si3N4/Ag/Si3N4 trilayers and (Si3N4/Ag)n/Si3N4 multilayers grown by alternating ion-beam sputtering have been studied by combining complementary characterization techniques such as transmission electron microscopy, spectroscopic ellipsometry and degenerate four-wave mixing. The linear optical response dominated by the surface plasmon resonance of Ag nanoparticles has been measured over the whole visible range while the third-order nonlinear susceptibility has been probed at the surface plasmon resonance wavelength. Due to the weak in-plane interaction between Ag nanoparticles, the linear and nonlinear optical responses of the Si3N4/Ag/Si3N4 trilayers are mainly influenced by the size and shape of the nanoparticles. A maximum value of 1.1 x 10(-7) esu has been found at 635 nm for the effective third-order nonlinear susceptibility of the trilayer with the highest amount of silver. The linear optical response of the (Si3N4/Ag)n/Si3N4 multilayers is shown to be dominated by the surface plasmon resonance of isolated layers of weakly interacting nanoparticles at wavelengths shorter than 600 nm whereas a contribution due to vertical interactions has been shown for higher wavelengths. Below the vertical percolation threshold, their nonlinear optical response at the surface plasmon resonance wavelength is similar to the one of an isolated assembly of nanoparticles, and the effective third-order nonlinear susceptibility is slightly increased by decreasing the thickness of the Si3N4 spacer.
A Study of Second and Third Order Models for the Tracking Subsystem of a Radar Guided Missile
1988-06-01
method is optimum in a search for an "ideal" missile. Target parameters which have an effect on the missile tracking system are analyzed and a target... system are analyzed and a target acceleration probability model is discussed. A two dimensional third order tracking model is simulated utilizing a Kalman...50 A. TACTICS FOR MISSILE DEFENSE ......... .. 53 IV. SYSTEM MODEL ...... ................. 56 A. COORDINATE SYSTEM
NASA Astrophysics Data System (ADS)
He, Chunying; Fan, Jingze; Li, Zhongguo; Gao, Yachen; Chen, Zhimin; Song, Yinglin; Wu, Yiqun; wang, Bin
2014-02-01
Composite film with alternating layers containing anionic 1,8,15,22-tetrakis (8-quinolineoxy-5-sulfonic acid)-phthalocyanine copper and cationic polydiallydimethylammonium chloride was fabricated by electrostatic self-assembled layer-by-layer (LBL) technique. The microstructure of the film was characterized by a series of techniques. The third-order nonlinear optical properties of the film were measured using 4f coherent imaging system with phase object (NIT-PO) with laser duration of 20 ps at the wavelength of 532 nm. The film exhibited excellent nonlinear absorption and self-focusing effect. The second-order molecular hyperpolarizability γ value of the film reaches as high as 1.54 × 10-29 esu.
Podesta, J. J.; Forman, M. A.; Smith, C. W.
2007-09-15
Laws governing the behavior of statistical third-order moments in the inertial range are among the few rigorous results in the theory of statistically homogeneous incompressible magnetohydrodynamic turbulence. These fundamental laws apply to both isotropic and anisotropic turbulence. Assuming that the turbulence is stationary in time and statistically axisymmetric under proper rotations about the direction of the mean magnetic field, it is shown that the general mathematical form of the tensor quantities appearing in these laws is constrained by symmetry to have a particular form. Using these forms, the general solutions of the law for the vector and pseudovector third-order moments F and F{sub C} are obtained in the limit of large kinetic Reynolds number and large magnetic Reynolds number. The physical meaning of the different terms in F and F{sub C} are investigated and a method for obtaining the cascade rates of energy {epsilon} and cross-helicity {epsilon}{sub C} from experimental data is described. The results show that the measurement of the cascade rates goes hand-in-hand with the measurement of the spatial anisotropy of the third-order moments F and F{sub C}. The theory developed here can be applied to measure the turbulent cascade rates of energy and cross-helicity in laboratory plasma experiments, numerical simulations, and the solar wind.
NASA Astrophysics Data System (ADS)
Tan, Min; Liu, Qiming
2016-12-01
Taking advantage of the channel confinement of mesoporous films to prevent the agglomeration of Ag nanoparticles to achieve large third-order optical nonlinearity in amorphous materials, Ag-loaded composite mesoporous silica film was prepared by the electrochemical deposition method on ITO substrate. Ag ions were firstly transported into the channels of mesoporous film by the diffusion and binding force of channels, which were reduced to nanoparticles by applying suitable voltage. The existence and uniform distribution of Ag nanoparticles ranging in 1-10 nm in the mesoporous silica thin films were exhibited by UV spectrophotometer, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. The third-order optical nonlinearity induced by Ag nanoparticles was studied by the Z-scan technique. Due to the local field surface plasmon resonance, the maximum third-order nonlinear optical susceptibility of Ag-loaded composite mesoporous silica film is 1.53×10-10 esu, which is 1000 times larger than that of the Ag-contained chalcogenide glasses which showed large nonlinearity in amorphous materials.
Zhang, Z; Tian, X
2005-01-01
The application of a recently proposed denoising implementation for obtaining cognitive evoked potentials (CEPs) at the single-trial level is shown. The aim of this investigation is to develop the technique of extracting CEPs by combining both the third-order correlation and the wavelet denoising methods. First, the noisy CEPs was passed through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It was shown that it is possible to estimate the filter impulse response on basis of a select third-order correlation slice (TOCS) of the input noisy CEPs. Second, the output from the third-order correlation filter is decomposed with bi-orthogonal splines at 5 levels. The CEPs is reconstructed by wavelet final approximation a
Third-order nonlinear optical properties and photophysical mechanism of a novel In-porphyrin polymer
NASA Astrophysics Data System (ADS)
Ni, Kaizao; Liu, Dajun; Li, Zhongguo; Xiao, Zhengguo; Yang, Junyi; Song, Yinglin
2014-12-01
We use the time-resolved degenerated PO pump-probe technique to investigate the nonlinear absorption and nonlinear refraction dynamics of a novel porphyrin derivate, Indium-Porphyrin functionalized with polymethylmethacrylate (InPor-MMA26), dissolved in DMF at 532 nm in picosecond domain simultaneously. The results indicate that the nonlinear optical responses are induced by solution molecular excited state nonlinearity only, without the existence of two-photon absorption or Kerr refraction. Combined with five-energy-level model, all nonlinear optical parameters are determined by analyzing the experimental curves and confirmed by 4 ns Z-scan at 532 nm. The sample has a good reverse saturable absorption and reasonable positive refraction. With the proper lifetime and intersystem crossing time, this sample can be a candidate for optical limiting. The polymer attached to porphyrin directly by chemical bonds. This makes it have better homogeneity compared to physical mixing in the form of film.
Kuo, Jer-Lai; Kuhs, Werner F
2006-03-02
We have studied the structure of ice-VI by examining all ice-rule-allowed structures in its primary unit cell of 10 water molecules with first principles methods. A significant amount of static distortions in the oxygen positions away from their crystallographic positions are found, which is in good agreements with significant higher-order terms in the atomic displacement parameters obtained from X-ray and neutron diffraction data. Structural anomalies (such as exceptionally short OH bonds and small H-O-H angles) noted in conventional crystal structure refinements were not seen in our ab initio calculations, and it is evident that these structural anomalies arose from oversimplified models in which static distortions are not properly accounted for. Our results also show that the molecular geometry of water in ice-VI is similar to but richer than those in ice-Ih and ice-VII. Larger distortions in bond lengths/angles and correlation between the molecular geometry and the neighboring environments were found. Different proton-ordering schemes proposed in the literature were examined, and our calculations provide evidence in favor of a ferroelectric phase of the proton-ordered counterpart of ice-VI at about 80 K.
NASA Astrophysics Data System (ADS)
Amudha, M.; Muthu, S.; Gunasekaran, B.; Praveen Kumar, P.
2017-10-01
Good optical quality single crystals of Benzimidazolium Maleate (BML), a new organic charge transfer molecular complex salt, were grown successfully by the slow evaporation solution growth technique using deionised water as solvent at room temperature. The grown crystals of BML were characterised by single crystal X-ray diffraction (XRD) and powder XRD which confirm that the crystal belongs to monoclinic system with the centrosymmetric space group P21/n. The presence of functional groups in the grown crystal was confirmed by Fourier transform infrared spectral analysis. The BML crystal is thermally stable up to 147.7 °C and it is found by TG-DTA analysis. The transparency of the crystal was identified using UV-Vis spectrophotometer. Vickers microhardness analysis shows the mechanical stability of the grown crystal. The dependence of dielectric properties with frequency and temperature were also studied. Nonlinear optical absorption coefficient determined from open aperture Z-scan analysis revealed that the BML crystal can serve as a promising candidate for optical limiting applications.
NASA Astrophysics Data System (ADS)
Aly, Shawkat M.; Abdulhalim, Lina G.; Besong, Tabot M. D.; Soldan, Giada; Bakr, Osman M.; Mohammed, Omar F.
2016-03-01
Efficient absorption of visible light and a long-lived excited state lifetime of silver nanoclusters (Ag29 NCs) are integral properties for these new clusters to serve as light-harvesting materials. Upon optical excitation, electron injection at Ag29 NC/methyl viologen (MV2+) interfaces is very efficient and ultrafast. Interestingly, our femto- and nanosecond time-resolved results demonstrate clearly that both dynamic and static electron transfer mechanisms are involved in photoluminescence quenching of Ag29 NCs.Efficient absorption of visible light and a long-lived excited state lifetime of silver nanoclusters (Ag29 NCs) are integral properties for these new clusters to serve as light-harvesting materials. Upon optical excitation, electron injection at Ag29 NC/methyl viologen (MV2+) interfaces is very efficient and ultrafast. Interestingly, our femto- and nanosecond time-resolved results demonstrate clearly that both dynamic and static electron transfer mechanisms are involved in photoluminescence quenching of Ag29 NCs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05328e
NASA Astrophysics Data System (ADS)
Patil, P. S.; Maidur, Shivaraj R.; Rao, S. Venugopal; Dharmaprakash, S. M.
2016-07-01
Transparent good quality single crystals of organic nonlinear optical material, 3, 4-Dimethoxy -4‧-methoxychalcone (DMMC) were grown by slow evaporation solution growth technique in acetone at ambient temperature. The lattice parameters were estimated from powder X-ray diffraction. The crystalline perfection has been evaluated by high resolution X-ray diffractometry (HRXRD). The UV-vis-NIR absorption spectrum reveals that the crystal is transparent between 440 nm and 900 nm for optical applications. The fluorescence spectrum shows a peak at about 482 nm and indicates that the crystal has a blue fluorescence emission. The third order nonlinear optical properties of solution of DMMC in N, N-Dimethylformamide (DMF) solvent has been investigated using Z-scan technique with femtosecond (fs) Ti:sapphire laser pulses at 800 nm wavelength. The calculated values of nonlinear refractive index, nonlinear absorption coefficient, and the magnitude of third-order susceptibility are of the order of - 7.7×10-14cm2/W, 1.7×10-9 cm/W and 6.7×10-12 e.s.u. respectively. The two photon absorption (2PA) cross section and molecular second-order hyperpolarizability values obtained is of the order of 10-49 cm4 s/photon/molecule and 2.8×10-31 e.s.u. respectively. The crystal shows optical-limiting (OL) effects for femtosecond laser pulses at 800 nm. The results suggest that the nonlinear properties investigated for DMMC are comparable with some of the reported chalcone derivatives and can be desirable for nonlinear optical applications.
Louzada, Marcel; Britton, Jonathan; Nyokong, Tebello; Khene, Samson
2017-09-19
This paper investigates the third-order nonlinear optical properties of 4α-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (α-SnOtBpPc) and 4β-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (β-SnOtBpPc) in different organic solvents. The third-order susceptibilities of α-SnOtBpPc and β-SnOtBpPc are reported in different solvents, using Z-scan techniques with 10 ns laser pulses at 532 nm. Their nonlinear absorption coefficient and absorption cross sections were also determined. The molecular imaginary components of the second-order hyperpolarizability Im[γ] of α-SnOtBpPc and β-SnOtBpPc were found to be 2.60 × 10(-31) and 2.94 × 10(-31) esu (tetrahydrofuran), 2.12 × 10(-31) and 2.54 × 10(-31) esu (chloroform), 3.06 × 10(-31) and 2.54 × 10(-31) esu (dichloromethane), and 1.27 × 10(-31) and 1.50 × 10(-31) esu (toluene), respectively. This study found that substitution at the α position has an effect of lowering the two-photon (2PA) cross section value for α-SnOtBpPc compared to that for β-SnOtBpPc, with values of 64.30 and 456.65 GM, respectively. The large 2PA cross section observed in β-SnOtBpPc is attributed to the decreased energy difference between the virtual state and the LUMO.
NASA Astrophysics Data System (ADS)
Mazaheri, Alireza; Nishikawa, Hiroaki
2015-11-01
In this paper, we construct second- and third-order hyperbolic residual-distribution schemes for general advection-diffusion problems on arbitrary triangular grids. We demonstrate that the accuracy of the second-order hyperbolic schemes in [J. Comput. Phys. 227 (2007) 315-352] and [J. Comput. Phys. 229 (2010) 3989-4016] can be greatly improved by requiring the scheme to preserve exact quadratic solutions. The improved second-order scheme can be easily extended to a third-order scheme by further requiring the exactness for cubic solutions. These schemes are constructed based on the SUPG methodology formulated in the framework of the residual-distribution method, and thus can be considered as economical and powerful alternatives to high-order finite-element methods. For both second- and third-order schemes, we construct a fully implicit solver by the exact residual Jacobian of the proposed second-order scheme, and demonstrate rapid convergence, typically with no more than 10-15 Newton iterations (and about 200-800 linear relaxations per Newton iteration), to reduce the residuals by ten orders of magnitude. We also demonstrate that these schemes can be constructed based on a separate treatment of the advective and diffusive terms, which paves the way for the construction of hyperbolic residual-distribution schemes for the compressible Navier-Stokes equations. Numerical results show that these schemes produce exceptionally accurate and smooth solution gradients on highly skewed and anisotropic triangular grids even for a curved boundary problem, without introducing curved elements. A quadratic reconstruction of the curved boundary normals and a high-order integration technique on curved boundaries are also provided in details.
NASA Astrophysics Data System (ADS)
Cheng, A.; Xu, K.
2012-12-01
This presentation describes the implementation and testing of a higher-order turbulence closure, an intermediately-prognostic higher-order turbulence closure (IPHOC), into the Community Atmosphere Model (CAM) version 5 (CAM5). The third-order turbulence closure introduces a joint double-Gaussian distribution of liquid water potential temperature, total water mixing ratio, and vertical velocity to represent any skewed turbulence circulations. The distribution is inferred from the first-, second-, and third-order moments of the variables given above and is used to diagnose cloud fraction and grid-mean liquid water mixing ratio, as well as the buoyancy term and fourth-order terms in the equations describing the evolution of the second- and third-order moments. In addition, a prognostic planetary boundary layer (PBL) height approach has been incorporated in IPHOC in order to resolve the strong inversion above PBL for the coarse general circulation model (GCM) vertical grid-spacing. The IPHOC replaces PBL, shallow convection, and cloud macrophysics parameterizations in CAM5. The coupling of CAM5 with IPHOC (CAM5-IPHOC) represents a more unified treatment of boundary layer and shallow convective processes. Results from global simulations are presented and suggest that CAM5-IPHOC can provide a better treatment of boundary layer clouds and processes, when compared to CAM5. At the GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI) cross section, CAM5-IPHOC tends to correct the underestimate of the stratocumulus and shallow cumulus clouds both in cloud cover and liquid water path by CAM5. The decoupling of stratocumulus clouds and the associated transition from stratocumulus-to-shallow cumulus clouds are also more realistic and reasonable.
NASA Astrophysics Data System (ADS)
Vivek, P.; Murugakoothan, P.
2014-06-01
A new organic NLO material 4-Bromoanilinium hydrogen phthalate was grown by slow evaporation technique. The solubility and metastable zone width were determined. The crystal belongs to monoclinic system with space group C2. Optical transmittance spectrum confirms the wide optical window. Absorption coefficient and band gap were calculated from transmittance. The thermal stability, laser-induced surface damage threshold and mechanical behaviour were analysed. The particle size-dependent second harmonic generation efficiency was evaluated by Kurtz-Perry powder method and existence of phase matching. The third-order optical study was measured by Z-scan studies. The dispersion of birefringence behaviour was studied.
NASA Astrophysics Data System (ADS)
Peramaiyan, G.; Pandi, P.; Jayaramakrishnan, V.; Das, Subhasis; Mohan Kumar, R.
2012-12-01
Optical quality γ-glycine single crystal of dimension 9 × 9 × 8 mm3 has been grown by slow cooling method in the presence of lithium nitrate. The third order nonlinear refractive index and nonlinear absorption coefficient of the grown crystal were measured by Z-scan studies. The dispersion of birefringence behaviour was studied by modified channelled spectrum method. The relative second harmonic generation efficiency of grown crystal was measured by Kurtz and Perry technique and phase matching angle was also measured using Nd:YAG laser.
Marquette, Ian
2009-01-15
We consider a superintegrable Hamiltonian system in a two-dimensional space with a scalar potential that allows one quadratic and one cubic integrals of motion. We construct the most general cubic algebra and we present specific realizations. We use them to calculate the energy spectrum. All classical and quantum superintegrable potentials separable in Cartesian coordinates with a third order integral are known. The general formalism is applied to quantum reducible and irreducible rational potentials separable in Cartesian coordinates in E{sub 2}. We also discuss these potentials from the point of view of supersymmetric and PT-symmetric quantum mechanics.
Hu, Gonghao; Miao, Hao; Mei, Hua; Zhou, Shuai; Xu, Yan
2016-05-10
The first polyoxometalates modified by a porphyrin-resembling planar Schiff base have been successfully designed and synthesized under hydrothermal conditions. The third-order NLO responses indicated that they are excellent third-order NLO materials. Their catalytic performances are also investigated.
Shafaghati, Leila; Razaghi-Moghadam, Zahra; Mohammadnejad, Javad
2017-08-28
Alcoholic liver disease (ALD) is a complex disease characterized by damages to the liver and is the consequence of excessive alcohol consumption over years. Since this disease is associated with several pathway failures, pathway reconstruction and network analysis are likely to explicit the molecular basis of the disease. To this aim, in this paper, a network medicine approach was employed to integrate interactome (protein-protein interaction and signaling pathways) and transcriptome data to reconstruct both a static network of ALD and a dynamic model for it. Several data sources were exploited to assemble a set of ALD-associated genes which further was used for network reconstruction. Moreover, a comprehensive literature mining reveals that there are four signaling pathways with crosstalk (TLR4, NF- [Formula: see text]B, MAPK and Apoptosis) which play a major role in ALD. These four pathways were exploited to reconstruct a dynamic model of ALD. The results assure that these two models are consistent with a number of experimental observations. The static network of ALD and its dynamic model are the first models provided for ALD which offer potentially valuable information for researchers in this field.
NASA Astrophysics Data System (ADS)
Salacuse, J. J.; Denton, A. R.; Egelstaff, P. A.; Tau, M.; Reatto, L.
1996-03-01
The method described in the preceding paper [J. J. Salacuse, A. R. Denton, and P. A. Egelstaff, preceding paper, Phys. Rev. E 53, 2382 (1996)] for computing the static structure factor S(Q) of a bulk fluid is used to analyze molecular dynamics computer simulation data for a model krypton fluid whose atoms interact via a truncated Aziz pair potential. Simulations have been carried out for two system sizes of N=706 and 2048 particles and two thermodynamic states, described by a common reduced temperature T*=1.51 and reduced densities ρ*=0.25 and 0.4. Results presented include the N-particle radial distribution function gN(r) and the bulk static structure factor S(Q). In addition we calculate the direct correlation function c(r) from the full S(Q). In comparison with corresponding predictions of the modified hypernetted chain theory, the results are generally in excellent agreement at all r and Q, to within random statistical errors in the simulation data.
NASA Astrophysics Data System (ADS)
Woodward, R. I.; Murray, R. T.; Phelan, C. F.; de Oliveira, R. E. P.; Runcorn, T. H.; Kelleher, E. J. R.; Li, S.; de Oliveira, E. C.; Fechine, G. J. M.; Eda, G.; de Matos, C. J. S.
2017-03-01
We report second- and third-harmonic generation in monolayer MoS2 as a tool for imaging and accurately characterizing the material’s nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive expressions relating experimental measurements to second- and third-order nonlinear sheet susceptibility magnitudes, obtaining values of | {χ }{{s}}(2)| =2.0× {10}-20 m2 V-1 and, for the first time for monolayer MoS2, | {χ }{{s}}(3)| =1.7× {10}-28 m3 V-2. These sheet susceptibilities correspond to effective bulk nonlinear susceptibility values of | {χ }{{b}}(2)| =2.9 × {10}-11 m V-1 and | {χ }{{b}}(3)| =2.4× {10}-19 m2 V-2, accounting for the sheet thickness. Experimental comparisons between MoS2 and graphene are also performed, demonstrating ˜3.4 times stronger third-order sheet nonlinearity in monolayer MoS2, highlighting the material’s potential for nonlinear photonics in the telecommunications C band.
NASA Astrophysics Data System (ADS)
Jayakrishnan, K.; Joseph, Antony; Bhattathiripad, Jayakrishnan; Ramesan, M. T.; Chandrasekharan, K.; Siji Narendran, N. K.
2016-04-01
We report our results on the identification of large order enhancement in nonlinear optical coefficients of polymerized indole and its comparative study with reference to its monomer counterpart. Indole monomer shows virtually little third order effects whereas its polymerized version exhibits phenomenal increase in its third order nonlinear optical parameters such as nonlinear refractive index and nonlinear absorption. Open aperture Z-scan trace of polyindole done with Q-switched Nd:YAG laser source (532 nm, 7 ns), shows β value as high as 89 cm/GW at a beam energy of 0.83 GW/cm2. Closed aperture Z-scan done at identical energies reveals nonlinear refractive index of the order of -3.55 × 10-17 m2/W. Band gap measurement of polyindole was done with UV-Vis absorption spectra and compared with that of Indole. FTIR spectra of the monomer and polymerized versions were recorded and relevant bond formations were confirmed from the characteristic peaks. Photo luminescent spectra were investigated to know the emission features of both molecules. Beam energy (I0) versus nonlinear absorption coefficient (β) plot indicates reverse saturable type of absorption behaviour in polyindole molecules. Degenerate Four Wave Mixing (DFWM) plot of polyindole reveals quite a cubic dependence between probe and phase conjugate signal and the resulting χ(3) is comparable with Z-scan results. Optical limiting efficiency of polyindole is comparable with certain derivatives of porphyrins, phthalocyanines and graphene oxides.
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; Desjarlais, M. P.
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g. diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently, the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elastic constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; Desjarlais, M. P.
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g., diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elastic constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.
NASA Astrophysics Data System (ADS)
Priakumari, R. Omegala; Sheba, S. Grace Sahaya; Gunasekaran, M.
2015-12-01
Single crystals of semiorganic sodium hydrogen maleate trihydrate (SHMT) were effectively grown from deionized water by solvent evaporation technique. The grown crystals were subjected to single crystal X-ray diffraction to know the precise information about the crystallographic structure. The SHMT crystal belongs to triclinic system with centrosymmetric space group of P-1. TGA/DTA analysis indicates that the grown crystal was thermally stable up to 249.6 °C. The UV-Visible spectrum revealed its high transparency nature and the cut off wavelength was found to be at 290 nm. Its mechanical behavior was assessed by Vickers microhardness measurements. Dielectric measurements were made over a wide range of frequency (50 Hz-1 MHz) at room temperature. Theoretical calculations for polarizability and optical constants were made which are necessary for device fabrication. The third-order nonlinear optical parameters were derived by Z-scan technique. The third-order nonlinear refractive index, absorption coefficient and susceptibility values were found to be -5.04112 × 10-11 cm2/W, 1.08717 × 10-3 cm/W and 6.35585 × 10-7 esu respectively.
NASA Astrophysics Data System (ADS)
Shanthi, A.; Krishnan, C.; Selvarajan, P.
2014-03-01
An organic single crystal of Urea Adipic acid (UAA) was successfully grown in methanol solvent by slow solvent evaporation technique at room temperature (30 °C). The structure of grown crystal was elucidated from the X-ray diffraction study and it belongs to monoclinic system with centrosymmetric space group P21/c. The optical transmission spectrum of UAA has been recorded and its theoretical calculations were carried out to determine the linear optical constants such as linear absorption coefficient, extinction coefficient, refractive index and reflectance etc. The third-order nonlinearities of UAA crystal have been investigated by Z-scan method. The values of nonlinear refractive index (n2), the absorption coefficient (β) and third-order nonlinear susceptibility (χ(3)) are found to be the order of 0.96 × 10-10 cm2/W, 1.248 × 10-4 cm/W and 6.44 × 10-8 esu respectively. Fourier Transform Infra Red and Raman spectroscopy studies reveal the intermolecular interactions present in the UAA sample. The dielectric and mechanical measurements of the title compound are also reported.
Third-Order Nonlinear Optic and Optical Limiting Properties of a Mn(iii) Transition Metal Complex
NASA Astrophysics Data System (ADS)
Karakas, Asli; Elmali, Ayhan; Yahsi, Yasemin; Kara, Hulya
N,N‧-bis(5-bromosalicylidene)propane-1,2-diamine-O,O‧,N,N‧)-manganese(III) chloride transition metal complex has been synthesized and characterized by elemental analysis and UV-vis spectroscopy. Its crystal structure has been determined using X-ray diffraction analysis. To provide an insight into the optical limiting (OL) behavior of the title compound, the third-order nonlinear optical (NLO) properties, one-photon absorption (OPA) and two-photon absorption (TPA) characterizations have been theoretically investigated by means of the time-dependent Hartree-Fock (TDHF), AM1 and configuration interaction (CI) methods, respectively. According to ab initio calculation results, the examined molecule exhibits second hyperpolarizabilities (γ) with non-zero values at the positions of TPA peaks, implying microscopic third-order optical nonlinearity. The maximum OPA wavelengths recorded by linear optical experiment and quantum mechanical computations are estimated in the UV region to be shorter than 400 nm, showing good optical transparency to the visible light. The TPA cross-sections (δ(ω)) at λ max(2) values indicate that the synthesized compound might possess OL phenomena, which are in accord with the experimental observations on the manganese complexes in the literature.
Shanthi, A; Krishnan, C; Selvarajan, P
2014-03-25
An organic single crystal of Urea Adipic acid (UAA) was successfully grown in methanol solvent by slow solvent evaporation technique at room temperature (30 °C). The structure of grown crystal was elucidated from the X-ray diffraction study and it belongs to monoclinic system with centrosymmetric space group P21/c. The optical transmission spectrum of UAA has been recorded and its theoretical calculations were carried out to determine the linear optical constants such as linear absorption coefficient, extinction coefficient, refractive index and reflectance etc. The third-order nonlinearities of UAA crystal have been investigated by Z-scan method. The values of nonlinear refractive index (n2), the absorption coefficient (β) and third-order nonlinear susceptibility (χ((3))) are found to be the order of 0.96×10(-10) cm(2)/W, 1.248×10(-4) cm/W and 6.44×10(-8) esu respectively. Fourier Transform Infra Red and Raman spectroscopy studies reveal the intermolecular interactions present in the UAA sample. The dielectric and mechanical measurements of the title compound are also reported.
NASA Astrophysics Data System (ADS)
Zhou, Yunshan; Shi, Zonghai; Zhang, Lijuan; ul Hassan, Sadaf; Qu, Ningning
2013-11-01
The third-order nonlinear optical properties of a Keplerate-type polyoxometalate (NH4)18[(Bu4N]24[Mo132O372(H2O)72(CH3COO)30]ṡ ca.7NH4CH3COOṡ ca.173H2O (denoted Bu4N-{Mo132}) in solution and in films of poly(methylmethacrylate) (denoted PMMA) matrix have been studied by the Z-scan method at 532 nm with a pulse duration of 20 ps. Experimental results show that both the solution and the solid films of Bu4N-{Mo132} have nonlinear self-defocusing effects and notable nonlinear reverse saturable absorption. Embedding Bu4N-{Mo132} as inclusion into PMMA host significantly improves the nonlinear absorption coefficient β, while it reduces the nonlinear refractive coefficient as a result of the higher concentration of Bu4N-{Mo132} in PMMA matrix than in solution. The magnitude of β for solid-state Bu4N-{Mo132} in films increases with the increasing amount of incorporated Bu4N-{Mo132}, while the third-order nonlinear refractive index n 2 decreases. Experimental results prove the high stability of Bu4N-{Mo132} in PMMA films in inorganic acidic and basic solutions. These studies indicate that Bu4N-{Mo132} in thin solid films of PMMA are potential candidates for fabricating nonlinear optical devices.
Third-order nonlinearity and passive Q-switching of Cr⁴⁺:YGG garnet crystal.
Wang, Shuxian; Zhang, Yuxia; Wu, Kui; Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Zhang, Guanghui; Xiong, Qihua
2015-05-15
We demonstrate the third-order nonlinear optical properties of Cr(4+):Y(3)Ga(5)O(12) (Cr(4+):YGG) and Q-switched lasers with Cr(4+):YGG as the saturable absorber for the first time to our knowledge. The third-order nonlinear properties, including the optical Kerr nonlinearity and saturable absorption, were systematically measured and analyzed in detail by using a Z-scan technique. The measured data show that Cr(4+):YGG has a large nonlinear refractive index, ground-state absorption cross section, and excited-state absorption cross section in contrast to Cr(4+):Y(3)Al(5)O(12) (Cr(4+):YAG). With a Nd:YGG crystal as the gain medium and a Cr(4+):YGG crystal as the saturable absorber, the passively Q-switched laser was performed. The shortest pulse width and largest pulse energy were achieved at the absorbed pump power of 8 W with the values of 9.1 ns and 26.1 μJ, respectively, corresponding to the average output power of 0.87 W and peak power of 2.9 kW. The results indicate that Cr(4+):YGG is an available and promising optical switcher for pulsed lasers.
Li, P H; Qu, Y L; Xu, X J; Zhu, Y W; Yu, T; Chin, K C; Mi, J; Gao, X Y; Lim, C T; Shen, Z X; Wee, A T S; Ji, W; Sow, C H
2006-04-01
We report a new morphology of "cactus" top-decorated aligned carbon nanotubes grown by the PECVD method using pure C2H2 gas. Unlike most previous reports, no additional carrier gas is used for pretreatment. Carbon nanotubes can still grow and maintain the tubular structure underneath the "cactus" tops. It is proposed that the H atoms produced by the dissociation of C2H2 activate the catalyst nanoparticles. Scanning electron microscopy (SEM) shows that the top "cactus" morphology is composed of a large quantity of small nanosheets. Transmission electron microscopy (TEM) reveals the amorphous carbon nature of these "cactus" structures. The formation of these "cactus" structures is possibly due to covalent absorption and reconstruction of carbon atoms on the broken graphite layers of nanotubes produced by the strong ion bombardment under plasma. The third-order optical nonlinearities and nonlinear dynamics are also investigated. The third-order nonlinear susceptibility magnitude /chi(3)/ is found to be 2.2 x 10(-11) esu, and the relaxation process takes place in about 1.8 ps.
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; Desjarlais, M. P.
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g. diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently, the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elastic constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; Desjarlais, M. P.
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g., diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elastic constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.
Vakarcs, G.; Vail, P.R.; Tari, G.; Pogácsás, Gy.; Mattick, R.E.; Szabo, A.
1994-01-01
Few studies exist in the geologic literature that show the distribution of seismic facies and depositional sequences within a lacustrine basin. The Pannonian Basin of Central Europe offers a unique opportunity to evaluate the influence of the eustatic signal on lacustrine deposition. Seismic stratigraphie and sedimentological studies indicate that the Middle Miocene-Early Pliocene infill of the transtensional Pannonian Basin was formed by large delta systems. Systematic sequence stratigraphie analysis of 6000 km of reflection seismic data and more than 100 hydrocarbon exploration wells in Hungary allowed the identification of twelve third-order sequence boundaries in the late Neogene sedimentary fill. This number of depositional sequences corresponds to that of the published global eustatic curve for this time period. Furthermore, based on magnetostratigraphic and radiometric data, the ages of these depositional sequences can be tentatively correlated with the global eustatic curve. The Pannonian Basin became isolated from the world sea at the Sarmatian/Pannonian (11.5 Ma) boundary and formed a large lake. The stratal patterns and sedimentary facies of individual systems tracts within the lacustrine sequences display the same characteristics as marine depositional sequences. The relatively low rate of thermal subsidence and the high rate of sediment supply resulted in a good sequence resolution. Within the third-order sequences higher-order sequences can be recognized with an average duration of about 0.1-0.5 Ma. ?? 1994.
Bentley, T. William
2015-01-01
Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides) exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1) to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3) are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides). Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride). PMID:26006228
NASA Astrophysics Data System (ADS)
Arivazhagan, T.; Siva Bala Solanki, S.; Rajesh, Narayana Perumal
2017-02-01
The butyl 4-hydroxybenzoate single crystal has been grown by vertical Bridgman technique using single wall ampoule. The cell parameters of the grown crystal are verified by single crystal X-ray diffraction analysis. The functional groups of the grown crystal were identified by Fourier transform infrared analysis. The melting, decomposition and crystallization point of the compound are determined by thermo gravimetric analysis and differential scanning calorimetric analysis. The mechanical properties of the grown crystal has been analyzed by Vickers microhardness method. The optical behavior of the grown crystal has been observed by UV-vis-NIR transmission spectroscopic analysis which shows that the lower cut-off wavelength lying at 293 nm and found that the energy band gap value is 4.05 eV. The blue light emission of the crystal was identified by photoluminescence studies. The positive third order nonlinear optical parameters like nonlinear refractive index (n2), nonlinear absorption co-efficient (β) and third order nonlinear susceptibility (χ3) of the grown crystal was calculated by Z-scan studies. The positive sign of nonlinear refractive index (n2) indicates that the crystal exhibits self focusing optical nonlinearity. The crystal exhibits good optical power limiting behavior.
NASA Astrophysics Data System (ADS)
Endres, Florian; Steinmann, Paul
2016-01-01
Ferroelectric functional materials are of great interest in science and technology due to their electromechanically coupled material properties. Therefore, ferroelectrics, such as barium titanate, are modeled and simulated at the continuum scale as well as at the atomistic scale. Due to recent advancements in related manufacturing technologies the modeling and simulation of smart materials at the nanometer length scale is getting more important not only to predict but also fundamentally understand the complex material behavior of such materials. In this study, we analyze the size effects of 109° nanodomain walls in ferroelectric barium titanate single crystals in the rhombohedral phase using a recently proposed extended molecular statics algorithm. We study the impact of domain thicknesses on the spontaneous polarization, the coercive field, and the lattice constants. Moreover, we discuss how the electromechanical coupling of an applied electric field and the introduced strain in the converse piezoelectric effect is affected by the thickness of nanodomains.
NASA Astrophysics Data System (ADS)
Ivanov, Vladimir V.; Zakharov, Anton B.; Adamowicz, Ludwik
2013-12-01
A new semi-empirical π-electron local coupled cluster theory has been developed to calculate static dipole polarisabilities and hyperpolarisabilities of extended π-conjugated systems. The key idea of the approach is the use of the ethylene molecular orbitals as the orbital basis set for π-conjugated compounds (the method is termed the Covalent Unbonded Molecules of Ethylene method, cue). Test calculations of some small model organic conjugated compounds demonstrate high accuracy of the version of the cue local coupled cluster theory developed in this work in comparison with the π-electron full configuration interaction (FCI) method. Calculations of different conjugated carbon-based oligomer chains (polyenes, polyynes, polyacenes, polybenzocyclobutadiene, etc.) demonstrate fast convergence (per π-electron) of the polarisability and hyperpolarisability values in the calculations when more classes of orbital excitations are included in the coupled cluster single and double (CCSD) excitation operator. The results show qualitatively correct dependence on the system size.
Endres, Florian Steinmann, Paul
2016-01-14
Ferroelectric functional materials are of great interest in science and technology due to their electromechanically coupled material properties. Therefore, ferroelectrics, such as barium titanate, are modeled and simulated at the continuum scale as well as at the atomistic scale. Due to recent advancements in related manufacturing technologies the modeling and simulation of smart materials at the nanometer length scale is getting more important not only to predict but also fundamentally understand the complex material behavior of such materials. In this study, we analyze the size effects of 109° nanodomain walls in ferroelectric barium titanate single crystals in the rhombohedral phase using a recently proposed extended molecular statics algorithm. We study the impact of domain thicknesses on the spontaneous polarization, the coercive field, and the lattice constants. Moreover, we discuss how the electromechanical coupling of an applied electric field and the introduced strain in the converse piezoelectric effect is affected by the thickness of nanodomains.
Molecularly engineered surfaces for cell biology: from static to dynamic surfaces.
Gooding, J Justin; Parker, Stephen G; Lu, Yong; Gaus, Katharina
2014-04-01
Surfaces with a well-defined presentation of ligands for receptors on the cell membrane can serve as models of the extracellular matrix for studying cell adhesion or as model cell surfaces for exploring cell-cell contacts. Because such surfaces can provide exquisite control over, for example, the density of these ligands or when the ligands are presented to the cell, they provide a very precise strategy for understanding the mechanisms by which cells respond to external adhesive cues. In the present feature article, we present an overview of the basic biology of cell adhesion before discussing surfaces that have a static presentation of immobile ligands. We outline the biological information that such surfaces have given us, before progressing to recently developed switchable surfaces and surfaces that mimic the lipid bilayer, having adhesive ligands that can move around the membrane and be remodeled by the cell. Finally, the feature article closes with some of the biological information that these new types of surfaces could provide.
Static Properties and Stark Effect of the Ground State of the HD Molecular Ion
NASA Technical Reports Server (NTRS)
Bhatia, A. K.; Drachman, Richard J.
1999-01-01
We have calculated static properties of the ground state of the HD(+) ion and its lowest-lying P-state without making use of the Born-Oppenheimer approximation, as was done in the case of H2(+) and D2(+) [Phys. Rev. A 58, 2787 (1998)]. The ion is treated as a three-body system whose ground state is spherically symmetric. The wavefunction is of generalized Hylleraas type, but it is necessary to include high powers of the internuclear distance to localize the nuclear motion. We obtain good values of the energies of the ground S-state and lowest P-state and compare them with earlier calculations. Expectation values are obtained for various operators, the Fermi contact parameters, and the permanent quadrupole moment. The cusp conditions are also calculated. The polarizability was then calculated using second-order perturbation theory with intermediate P pseudostates. Since the nuclei in HD(+) are not of equal mass there is dipole coupling between the lowest two rotational states, which are almost degenerate. This situation is carefully analyzed, and the Stark shift is calculated variationally as a function of the applied electric field.
Tretyakov, Nikita; Müller, Marcus; Todorova, Desislava; Thiele, Uwe
2013-02-14
We study equilibrium properties of polymer films and droplets on a solid substrate employing particle-based simulation techniques (molecular dynamics) and a continuum description. Parameter-passing techniques are explored that facilitate a detailed comparison of the two models. In particular, the liquid-vapor, solid-liquid, and solid-vapor interface tensions, and the Derjaguin or disjoining pressure are determined by molecular dynamics simulations. This information is then introduced into continuum descriptions accounting for (i) the full curvature and (ii) a long-wave approximation of the curvature (thin film model). A comparison of the dependence of the contact angle on droplet size indicates that the theories agree well if the contact angles are defined in a compatible manner.
2008-12-01
estimated internal pressure of 50 GPa. Quantum molecular dynamics simulations of hypervelocity collisions of NDs show that upon collision shock...experiments exploring potential SBE materials such as carbon, silicon, borides and nitrides [Al’tschuler, 1990 and 1991]. Reports generated by...Our results are in excellent agreement with EOS models published by others over a wide range of pressures and temperatures. Our results provide
NASA Astrophysics Data System (ADS)
Xu, Liang; Zhang, Dingfeng; Zhou, Yecheng; Zheng, Yusen; Cao, Liu; Jiang, Xiao-Fang; Lu, Fushen
2017-08-01
In this paper, mono- and di-4-N,N-bis(4-methoxylphenyl)aniline-substituted anthraquinone have been designed and synthesized through Suzuki reaction. For mono-4-N,N-bis(4-methoxylphenyl)aniline-substituted anthraquinone, polymorphous crystal structures have been obtained in different crystallization conditions. Electrochemical characterization combined with theoretical calculation suggests that the addition of a second triphenylamine unit causes a larger band gap with higher lying LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital). The linear optical property shows that the introduction of a second triphenylamine unit bring about a significant hyperchromic effect with the extinction coefficients increasing from 11199 M-1 cm-1 to 22136 M-1 cm-1. The third-order nonlinear optical properties indicate that the introduction of a second triphenylamine unit lead to a much larger nonlinear absorption coefficient and two-photon absorption cross section, with the relevant value increasing from 2.04 × 10-12 cm W-1 to 3.91 × 10-12 cm W-1, and from 148 GM to 286 GM, respectively.
NASA Astrophysics Data System (ADS)
Pitoňák, Martin; Šprlák, Michal; Tenzer, Robert
2017-05-01
We investigate a numerical performance of four different schemes applied to a regional recovery of the gravity anomalies from the third-order gravitational tensor components (assumed to be observable in the future) synthetized at the satellite altitude of 200 km above the mean sphere. The first approach is based on applying a regional inversion without modelling the far-zone contribution or long-wavelength support. In the second approach we separate integral formulas into two parts, that is, the effects of the third-order disturbing tensor data within near and far zones. Whereas the far-zone contribution is evaluated by using existing global geopotential model (GGM) with spectral weights given by truncation error coefficients, the near-zone contribution is solved by applying a regional inversion. We then extend this approach for a smoothing procedure, in which we remove the gravitational contributions of the topographic-isostatic and atmospheric masses. Finally, we apply the remove-compute-restore (r-c-r) scheme in order to reduce the far-zone contribution by subtracting the reference (long-wavelength) gravity field, which is computed for maximum degree 80. We apply these four numerical schemes to a regional recovery of the gravity anomalies from individual components of the third-order gravitational tensor as well as from their combinations, while applying two different levels of a white noise. We validated our results with respect to gravity anomalies evaluated at the mean sphere from EGM2008 up to the degree 250. Not surprisingly, better fit in terms of standard deviation (STD) was attained using lower level of noise. The worst results were gained applying classical approach, STD values of our solution from Tzzz are 1.705 mGal (noise value with a standard deviation 0.01 × 10 - 15m - 1s - 2) and 2.005 mGal (noise value with a standard deviation 0.05 × 10 - 15m - 1s - 2), while the superior from r-c-r up to the degree 80, STD fit of gravity anomalies from Tzzz
NASA Astrophysics Data System (ADS)
Bornacelli, Jhovani; Torres-Torres, Carlos; Silva-Pereyra, Héctor Gabriel; Rodríguez-Fernández, Luis; Avalos-Borja, Miguel; Cheang-Wong, Juan Carlos; Oliver, Alicia
2017-06-01
A systematic study has been carried out to investigate photoluminescence and third order nonlinear ultraviolet properties exhibited by platinum nanoparticles nucleated in a high-purity silica matrix. The modification in the characteristic photoluminescence spectra of the nanocomposites, ranging between 400 and 600 nm, was obtained with the assistance of a thermal annealing process that changed the average size of the platinum nanoparticles. The influence of temperature, between 200 °C-1100 °C, during the thermal treatment of the nanostructures was analyzed. UV-vis spectroscopy studies corroborated changes in the optical absorption resonances of the ion-implanted samples after annealing, which could then be correlated with the average size of the nanoparticles. The estimated average size was also corroborated by transmision electron microscopy. For temperatures below 600 °C the system is mainly composed of ultra-small photoluminescent platinum nanoparticles. Larger platinum nanoparticles were formed at higher annealing temperatures but photoluminescence quenching was observed as the typical plasmonics response of larger metal nanoparticles started to emerge. The photoluminescence emission for samples with a particle size of less than 2 nm is enhanced approximately 12 fold with respect to the samples with a particle size in the range of 3-7 nm. Differences in the resulting photoluminescence spectra were revealed by substituting the participation of argon, hydrogen or nitrogen, as environmental gases for thermal annealing. A weak PL emission, featuring 1.5 nW at a laser excitation power of 800 μW, related to larger platinum nanoparticles was observed. New emission peaks emerging from the larger platinum nanoparticles were associated with possible hydrogen adsorption on the nanoparticles’ surface. Third order nonlinear ultraviolet measurements were conducted using a time-resolved two-wave mixing method with self-diffraction at 355 nm wavelength. The observed self
Bornacelli, Jhovani; Torres-Torres, Carlos; Silva-Pereyra, Héctor Gabriel; Rodríguez-Fernández, Luis; Avalos-Borja, Miguel; Cheang-Wong, Juan Carlos; Oliver, Alicia
2017-05-09
A systematic study has been carried out to investigate photoluminescence and third order nonlinear ultraviolet properties exhibited by platinum nanoparticles nucleated in a high-purity silica matrix. The modification in the characteristic photoluminescence spectra of the nanocomposites, ranging between 400 and 600 nm, was obtained with the assistance of a thermal annealing process that changed the average size of the platinum nanoparticles. The influence of temperature, between 200 °C-1100 °C, during the thermal treatment of the nanostructures was analyzed. UV-vis spectroscopy studies corroborated changes in the optical absorption resonances of the ion-implanted samples after annealing, which could then be correlated with the average size of the nanoparticles. The estimated average size was also corroborated by transmision electron microscopy. For temperatures below 600 °C the system is mainly composed of ultra-small photoluminescent platinum nanoparticles. Larger platinum nanoparticles were formed at higher annealing temperatures but photoluminescence quenching was observed as the typical plasmonics response of larger metal nanoparticles started to emerge. The photoluminescence emission for samples with a particle size of less than 2 nm is enhanced approximately 12 fold with respect to the samples with a particle size in the range of 3-7 nm. Differences in the resulting photoluminescence spectra were revealed by substituting the participation of argon, hydrogen or nitrogen, as environmental gases for thermal annealing. A weak PL emission, featuring 1.5 nW at a laser excitation power of 800 μW, related to larger platinum nanoparticles was observed. New emission peaks emerging from the larger platinum nanoparticles were associated with possible hydrogen adsorption on the nanoparticles' surface. Third order nonlinear ultraviolet measurements were conducted using a time-resolved two-wave mixing method with self-diffraction at 355 nm wavelength. The observed self
Ramos, Sergio Luis L M; Ogino, Michihiko; Oguni, Masaharu
2015-01-28
We investigated the thermal properties of liquid methylcyclohexane and racemic sec-butylcyclohexane, as representatives of a molecular system with only dispersion-force intermolecular interactions, confined in the pores (thickness/diameter d = 12, 6, 1.1 nm) of silica gels by adiabatic calorimetry. The results imply a heterogeneous picture for molecular aggregate under confinement consisting of an interfacial region and an inner pore one. In the vicinity of a glass-transition temperature T(g,bulk) of bulk liquid, two distinguishable relaxation phenomena were observed for the confined systems and their origins were attributed to the devitrification, namely glass transition, processes of (1) a layer of interfacial molecules adjacent to the pore walls and (2) the molecules located in the middle of the pore. A third glass-transition phenomenon was observed at lower temperatures and ascribed to a secondary relaxation process. The glass transition of the interfacial-layer molecules was found to proceed at temperatures rather above T(g,bulk), whereas that of the molecules located in the inner pore region occurred at temperatures below T(g,bulk). We discuss the reason why the molecules located in different places in the pores reveal the respectively different dynamical properties.
Chen, Zheng; Huang, Hongying; Yan, Jue
2015-12-21
We develop 3rd order maximum-principle-satisfying direct discontinuous Galerkin methods [8], [9], [19] and [21] for convection diffusion equations on unstructured triangular mesh. We carefully calculate the normal derivative numerical flux across element edges and prove that, with proper choice of parameter pair (β_{0},β_{1}) in the numerical flux formula, the quadratic polynomial solution satisfies strict maximum principle. The polynomial solution is bounded within the given range and third order accuracy is maintained. There is no geometric restriction on the meshes and obtuse triangles are allowed in the partition. As a result, a sequence of numerical examples are carried out to demonstrate the accuracy and capability of the maximum-principle-satisfying limiter.
Chen, Zheng; Huang, Hongying; Yan, Jue
2015-12-21
We develop 3rd order maximum-principle-satisfying direct discontinuous Galerkin methods [8], [9], [19] and [21] for convection diffusion equations on unstructured triangular mesh. We carefully calculate the normal derivative numerical flux across element edges and prove that, with proper choice of parameter pair (β0,β1) in the numerical flux formula, the quadratic polynomial solution satisfies strict maximum principle. The polynomial solution is bounded within the given range and third order accuracy is maintained. There is no geometric restriction on the meshes and obtuse triangles are allowed in the partition. As a result, a sequence of numerical examples are carried out to demonstratemore » the accuracy and capability of the maximum-principle-satisfying limiter.« less
Cobb, J.W.
1995-02-01
There is an increasing need for more accurate numerical methods for large-scale nonlinear magneto-fluid turbulence calculations. These methods should not only increase the current state of the art in terms of accuracy, but should also continue to optimize other desired properties such as simplicity, minimized computation, minimized memory requirements, and robust stability. This includes the ability to stably solve stiff problems with long time-steps. This work discusses a general methodology for deriving higher-order numerical methods. It also discusses how the selection of various choices can affect the desired properties. The explicit discussion focuses on third-order Runge-Kutta methods, including general solutions and five examples. The study investigates the linear numerical analysis of these methods, including their accuracy, general stability, and stiff stability. Additional appendices discuss linear multistep methods, discuss directions for further work, and exhibit numerical analysis results for some other commonly used lower-order methods.
Behzadi, Kobra; Baghelani, Masoud
2013-01-01
This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator. PMID:25685504
Investigation of the third-order nonlinear property of Ge-Se-Te glasses at mid-infrared
NASA Astrophysics Data System (ADS)
Sun, Lihong; Chen, Feifei; Xu, Yinsheng; Huang, Yicong; Liu, Shuo; Zhao, Zheming; Wang, Xunsi; Zhang, Peiqing; Dai, Shixun; Zhang, Xianghua
2016-09-01
In this study, a series of Ge20Te x Se(80- x) ( x = 0, 5, 10, 20, 30, 60, 70) chalcogenide glasses were prepared using conventional melt-quenching technique. Through absorption spectra analysis, the optical Tauc gaps were derived in detail along the increase in the Te content which can be supported by structural changing of glass network shown by Raman spectra. The third-order optical nonlinearity of the glasses at mid-infrared wavelength of 3.1 μm was investigated by traditional Z-scan method. The nonlinear refractive index of the glasses increased with the increase in the Te content, typically the measured nonlinear refractive index of Ge20Se50Te30 glass increased to 8.2 ± 1.2 × 10-18 m2/W. The relationship between the nonlinear refractive index and the optical band gap was analyzed.
NASA Astrophysics Data System (ADS)
Li, Baoming; Shi, Mingwei; Yan, Dong; Bai, Mengdi
2016-10-01
MWCNTs/poly (pyrrolyl methine) composites with the different contents of MWCNTs were synthesized by in-situ ultrasonic polymerization, and their structures and photophysical properties were also investigated. The results revealed that the third-order nonlinear optical susceptibility of MWCNTs/PHPDTBE composite showed a rapid increase with the increase of MWCNTs' content, and obtained a maximum value of 3.41 × 10-7 esu, which was almost ten times larger than that of PHPDTBE of 3.49 × 10-8 esu. The enhanced optical nonlinearity was attributed to strong photoinduced electron transfer from PHPDTBE to MWCNTs by right of their strong noncovalent π-π interaction in the photoexcited state.
Zhou Yu; Simon, Jason; Liu Jianbin; Shih, Yanhua
2010-04-15
In a near-field three-photon correlation measurement, we observed the third-order temporal and spatial correlation functions of chaotic thermal light in the single-photon counting regime. In the study, we found that the probability of jointly detecting three randomly radiated photons from a chaotic thermal source by three individual detectors is 6 times greater if the photodetection events fall in the coherence time and coherence area of the radiation field than if they do not. From the viewpoint of quantum mechanics, the observed phenomenon is the result of three-photon interference. By making use of this property, we measured the three-photon thermal light lensless ghost image of a double spot and achieved higher visibility compared with the two-photon thermal light ghost image.
An assessment of four-noded plate finite elements based on a generalized third-order theory
NASA Astrophysics Data System (ADS)
Averill, R. C.; Reddy, J. N.
1992-06-01
Plate finite elements based on the generalized third-order theory of Reddy and the first-order shear deformation theory are analyzed and compared on the basis of thick and thin plate modeling behavior, distortion sensitivity, overall accuracy, reliability, and efficiency. In particular, several four-noded Reddy-type elements and the nine-noded Lagrangian and heterosis (Mindlin-type) plate elements are analyzed to assess their behavior in bending, vibration, and stability of isotropic and laminated composite plates. A four-noded Reddy-type element is identified which is free of all spurious stiffness and zero energy modes, computationally efficient, and suitable for use in any general-purpose finite element program.
An assessment of four-noded plate finite elements based on a generalized third-order theory
NASA Technical Reports Server (NTRS)
Averill, R. C.; Reddy, J. N.
1992-01-01
Plate finite elements based on the generalized third-order theory of Reddy and the first-order shear deformation theory are analyzed and compared on the basis of thick and thin plate modeling behavior, distortion sensitivity, overall accuracy, reliability, and efficiency. In particular, several four-noded Reddy-type elements and the nine-noded Lagrangian and heterosis (Mindlin-type) plate elements are analyzed to assess their behavior in bending, vibration, and stability of isotropic and laminated composite plates. A four-noded Reddy-type element is identified which is free of all spurious stiffness and zero energy modes, computationally efficient, and suitable for use in any general-purpose finite element program.
Mueller, Alexander; Fuerbach, Alexander
2016-03-20
The standard technique commonly utilized to introduce large amounts of negative group delay dispersion (GDD) into the beam path of ultrashort laser pulses with low insertion losses is the use of a pair of prisms in a double pass configuration. However, one disadvantage of this approach is the unavoidable introduction of additional high-order spectral phase errors, most notably third-order dispersion (TOD) due to the characteristics of the refractive index of available optical materials. In this paper we provide an overview of the dispersive properties of more than 100 common types of optical glasses, used either as a bulk stretcher or in a prism compressor configuration. In addition, we present a novel method that enables independent control of GDD and TOD in a prism-only setup. The performance of different prism combinations is analyzed numerically, and design guidelines are given.
NASA Astrophysics Data System (ADS)
Dhavamurthy, M.; Raja, R.; Syed Suresh Babu, K.; Mohan, R.
2016-08-01
Guanidinium cinnamate (GUCN), a single crystal, was grown by slow evaporation technique. Single-crystal X-ray diffraction study revealed that GUCN crystal belongs to monoclinic crystal system with the space group P21/c. Thermal studies revealed that the GUCN is thermally stable up to 238 °C. The optical transmittance studies were carried out for the crystal, and the lower cutoff wavelength of the grown crystal was observed at 322 nm. The luminescent study showed that the GUCN crystal has high degree of luminescence. Third-order nonlinear refractive index n2, nonlinear absorption coefficient β and susceptibility χ(3) parameters were estimated by Z-scan technique. The four independent tensor coefficients ɛ11, ɛ22, ɛ33 and ɛ13 of dielectric permittivities for monoclinic GUCN were calculated. The mechanical properties of the grown crystals were studied using Vickers micro-hardness tester at different planes.
Enhancement of third-order nonlinear optical susceptibility of Alq_{3} in polar aprotic solvents.
Derkowska-Zielinska, Beata
2017-02-01
The influence of solvent polarity on nonlinear optical properties of tris-(8-hydroxyquinoline)-aluminum (Alq_{3}) was investigated by the degenerate four-wave mixing method at the 532 nm. It was obtained that the effective values of the third-order nonlinear optical susceptibility (χeff⟨3⟩) and the second-order hyperpolarizability (γ_{eff}) of Alq_{3} depend on the solvent polarity. Additionally, it was found that Alq_{3} dissolved in dimethyl sulfoxide has the highest values of χeff⟨3⟩ and γ_{eff}. Furthermore, two Stegeman's figures of merit were also calculated. The obtained results suggest that Alq_{3} is also promising material for application in all-optical signal processing devices.
Dridi, Kais; Benhsaien, Abdessamad; Zhang, Jessica; Hinzer, Karin; Hall, Trevor J
2014-08-11
We report on the design and characterization of a re-growth free InGaAsP/InP multiple quantum well two-electrode laterally coupled distributed feedback (LC-DFB) lasers. Third-order surface etched gratings have been defined on the ridge sidewalls along the laser cavity by means of stepper lithography. The lasers oscillate in single-mode around 1560 nm with high side mode suppression ratios (>52 dB), a wavelength tuning (≥ 3nm), an output power (≥ 6 mW), and narrow linewidth (<170 kHz) under various current injection ranges at room temperature. A minimum linewidth of 94 kHz has been recorded for 1500 µm-long two-electrode LC-DFB laser while providing non-uniform current injection through the two electrodes. The effect of the width of the inter-electrode gap on these different performance measures is also studied.
A clock steering method: using a third-order type 3 DPLL equivalent to a Kalman filter with a delay
NASA Astrophysics Data System (ADS)
Wu, Yiwei; Gong, Hang; Zhu, Xiangwei; Ou, Gang
2015-12-01
In this paper we propose a new clock steering method, which uses a third-order type 3 digital phase locked loop (DPLL) which is equivalent to a Kalman filter with a delay. A general overview of the theoretical framework is described in detail including the transfer functions, the structure and control values, the specifications, and the approach to choosing a parameter. Simulations show that the performance of the time and frequency steering errors and the frequency stability are quite desirable. Comparing with traditional clock steering methods, it is easier to work with just one parameter. The DPLL method satisfies the requirements of generating a local representation of universal time coordinated and the system time of a global navigation satellite system.
NASA Astrophysics Data System (ADS)
Dakova, D.; Dakova, A.; Slavchev, V.; Staykov, P.; Kovachev, L.
2016-01-01
In last two decades the phenomena resulting from the evolution of ultra-short laser pulses in nonlinear dispersive medium actively are being studied. The most commonly used equation for describing the dynamics of optical pulses in one-dimensional and planar waveguides is the standard nonlinear Schrodinger equation (NSE). It works very well for nanosecond and picosecond laser pulses, but in the frames of femtosecond optics, it is necessary two additional terms to be included. They are responsible for higher order of linear dispersion and dispersion of nonlinearity. These effects are significant in the range of ultra-short light pulses. In the present paper, it is presented a theoretical model of the propagation of optical solitons. We found an exact analytical soliton solution of the modified NSE, including third order of linear dispersion and dispersion of nonlinearity. It is possible to observe a soliton as a result of the dynamic balance between effects of higher order of dispersion and nonlinearity.
Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source
Corona, Maria; Garay-Palmett, Karina; U'Ren, Alfred B.
2011-09-15
We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.
NASA Astrophysics Data System (ADS)
Karvonen, Lasse; Alasaarela, Tapani; Jussila, Henri; Mehravar, Soroush; Chen, Ya; Säynätjoki, Antti; Norwood, Robert A.; Peyghambarian, Nasser; Kieu, Khanh; Honkanen, Seppo; Lipsanen, Harri
2014-03-01
We demonstrate a novel atomic layer deposition (ALD) process to make high quality nanocrystalline titanium dioxide (TiO2) and zinc oxide (ZnO) with intermediate Al2O3 layers to limit the crystal size. The waveguide losses of TiO2/Al2O3 nanolaminates measured using the prism coupling method for both 633 nm and 1551 nm wavelengths are as low as 0.2 +/- 0.1 dB/mm with the smallest crystal size. We also show that the third-order optical nonlinearity in ZnO/Al2O3 nanolaminates can be enhanced by nanoscale engineering of the thin film structure.
NASA Astrophysics Data System (ADS)
Rustad, James R.; Felmy, Andrew R.; Hay, Benjamin P.
1996-05-01
Molecular statics calculations are used to model the major FeOOH polymorphs and hematite. The potentials were taken from a previous investigation of Fe(III) in aqueous solutions which involved the extrapolation of the gas-phase Fe(III)-OH 2 potential energy surface to the solvated hexaaqua complex. Using this model for the solid phases, lattice parameters for goethite, akaganeite, lepidocrocite, and hematite are generally within 4% of experiment. Internal energies (at 0 K) were computed for each structure; lepidocrocite is energetically the most stable polymorph, followed by akaganeite, with goethite being the least stable. While the model exhibits some variances with experiment, it performs remarkably well, despite the challenging constraint of being consistent with a dissociating molecular dynamics model for water in its gas, aqueous, and solid phases. Because of this consistency, the model allows qualitative theoretical treatment of previously unapproachable problems in mineral-water interface geochemistry. We apply the model to identify surface species on the solvated (110) surface of goethite.
Using bifurcations in the determination of lock-in ranges for third-order phase-locked loops
NASA Astrophysics Data System (ADS)
Piqueira, José Roberto Castilho
2009-05-01
Transmission and switching in digital telecommunication networks require distribution of precise time signals among the nodes. Commercial systems usually adopt a master-slave (MS) clock distribution strategy building slave nodes with phase-locked loop (PLL) circuits. PLLs are responsible for synchronizing their local oscillations with signals from master nodes, providing reliable clocks in all nodes. The dynamics of a PLL is described by an ordinary nonlinear differential equation, with order one plus the order of its internal linear low-pass filter. Second-order loops are commonly used because their synchronous state is asymptotically stable and the lock-in range and design parameters are expressed by a linear equivalent system [Gardner FM. Phaselock techniques. New York: John Wiley & Sons; 1979]. In spite of being simple and robust, second-order PLLs frequently present double-frequency terms in PD output and it is very difficult to adapt a first-order filter in order to cut off these components [Piqueira JRC, Monteiro LHA. Considering second-harmonic terms in the operation of the phase detector for second order phase-locked loop. IEEE Trans Circuits Syst I 2003;50(6):805-9; Piqueira JRC, Monteiro LHA. All-pole phase-locked loops: calculating lock-in range by using Evan's root-locus. Int J Control 2006;79(7):822-9]. Consequently, higher-order filters are used, resulting in nonlinear loops with order greater than 2. Such systems, due to high order and nonlinear terms, depending on parameters combinations, can present some undesirable behaviors, resulting from bifurcations, as error oscillation and chaos, decreasing synchronization ranges. In this work, we consider a second-order Sallen-Key loop filter [van Valkenburg ME. Analog filter design. New York: Holt, Rinehart & Winston; 1982] implying a third order PLL. The resulting lock-in range of the third-order PLL is determined by two bifurcation conditions: a saddle-node and a Hopf.
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; ...
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g. diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently, the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elasticmore » constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.« less
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; ...
2016-05-23
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g., diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elasticmore » constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Lastly, our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.« less
NASA Astrophysics Data System (ADS)
Thankappan, Aparna; Thomas, Sheenu; Nampoori, V. P. N.
2013-10-01
We report on the solvent effect on the third order optical nonlinearity of betanin natural dye extracted from red beet root and their third order nonlinear optical (NLO) properties have been studied using a Q-switched Nd:YAG laser at 532 nm. The third order nonlinearity of these samples are dominated by nonlinear absorption, which leads to strong optical limiting and their strength is influenced by the solvent used, suggesting that betanin natural dyes are promising candidate for the development of photonic nonlinear optic devices.
Equilibrium fluctuations of liquid state static properties in a subvolume by molecular dynamics.
Heyes, D M; Dini, D; Smith, E R
2016-09-14
System property fluctuations increasingly dominate a physical process as the sampling volume decreases. The purpose of this work is to explore how the fluctuation statistics of various thermodynamic properties depend on the sampling volume, using molecular dynamics (MD) simulations. First an examination of various expressions for calculating the bulk pressure of a bulk liquid is made, which includes a decomposition of the virial expression into two terms, one of which is the Method of Planes (MOP) applied to the faces of the cubic simulation cell. Then an analysis is made of the fluctuations of local density, temperature, pressure, and shear stress as a function of sampling volume (SV). Cubic and spherical shaped SVs were used within a spatially homogeneous LJ liquid at a state point along the melting curve. It is shown that the MD-generated probability distribution functions (PDFs) of all of these properties are to a good approximation Gaussian even for SV containing only a few molecules (∼10), with the variances being inversely proportional to the SV volume, Ω. For small subvolumes the shear stress PDF fits better to a Gaussian than the pressure PDF. A new stochastic sampling technique to implement the volume averaging definition of the pressure tensor is presented, which is employed for cubic, spherical, thin cubic, and spherical shell SV. This method is more efficient for less symmetric SV shapes.
Equilibrium fluctuations of liquid state static properties in a subvolume by molecular dynamics
NASA Astrophysics Data System (ADS)
Heyes, D. M.; Dini, D.; Smith, E. R.
2016-09-01
System property fluctuations increasingly dominate a physical process as the sampling volume decreases. The purpose of this work is to explore how the fluctuation statistics of various thermodynamic properties depend on the sampling volume, using molecular dynamics (MD) simulations. First an examination of various expressions for calculating the bulk pressure of a bulk liquid is made, which includes a decomposition of the virial expression into two terms, one of which is the Method of Planes (MOP) applied to the faces of the cubic simulation cell. Then an analysis is made of the fluctuations of local density, temperature, pressure, and shear stress as a function of sampling volume (SV). Cubic and spherical shaped SVs were used within a spatially homogeneous LJ liquid at a state point along the melting curve. It is shown that the MD-generated probability distribution functions (PDFs) of all of these properties are to a good approximation Gaussian even for SV containing only a few molecules (˜10), with the variances being inversely proportional to the SV volume, Ω. For small subvolumes the shear stress PDF fits better to a Gaussian than the pressure PDF. A new stochastic sampling technique to implement the volume averaging definition of the pressure tensor is presented, which is employed for cubic, spherical, thin cubic, and spherical shell SV. This method is more efficient for less symmetric SV shapes.
Wang, Qi; Huang, Xiaoqing; Nakamura, Akihiro; Burchard, Walther; Hallett, F Ross
2005-12-12
Water soluble polysaccharides from soybean (SSPS) have a pectin-like structure and are used as stabilisers in acidified beverages. Physicochemical properties such as structure, molecular weight and shape or conformation are primary factors controlling their functional properties. Two soybean polysaccharides, a native SSPS and a modified SSPS treated with beta-(1-->4)-D-galactosidase (GPase/SSPS) were studied by dynamic and static light scattering (DLS, SLS) and size exclusion chromatography (SEC). Consecutive filtrations using a range of membrane pore size removed a small fraction of macromolecular aggregates from dilute polysaccharide solutions with relatively little effect on the major component molecules as monitored by DLS and SEC measurements. Access to aggregate-free dilute solutions of SSPS and GPase/SSPS allowed the direct measurement of molecular characteristics. SLS results showed that SSPS had a weight average molecular weight of (645+/-11)x 10(3)g/mol and a radius of gyration, Rg, of (23.5+/-2.8)nm. By comparing R(g) with the hydrodynamic radius, Rh (21.1+/-0.5 nm) obtained from DLS, the structural parameter rho (Rg/Rh) was found to be 1.1, suggesting that SSPS has an overall globular shape due to a highly branched structure. The modified SSPS had a significantly lower molecular weight (287+/-18)x 10(3)g/mol but a similar radius of gyration (23.2+/-1.7 nm). The structure parameter rho of GPase/SSPS was higher (rho=1.3) because of a smaller hydrodynamic radius (17.7+/-1.8 nm). This suggests that GPase/SSPS has a much less branched structure yet still differs significantly from a linear random coil conformation (rho=1.7-2.0). The results derived from SLS and DLS are in agreement with the conclusions obtained from a chemical analysis where the reduction of molecular weight of GPase/SSPS was caused by the cleavage of galactan side chains.
NASA Astrophysics Data System (ADS)
Senthilkumar, Kabali; Thirumoorthy, Krishnan; Vinitha, G.; Soni, Kiran; Bhuvanesh, Nattamai S. P.; Palanisami, Nallasamy
2017-01-01
The d10 metal complexes based on 3-methyl-5-ferrocenyl-1H-pyrazole (L = 3-Me-5-FcPz) ligand [M(L)4(NO3)2] Zn=(1) and Cd=(2), [Hg(L)4(NO3)2].dmf (3) have been synthesized and characterized by FT-IR, NMR, UV-Vis and elemental analysis. The molecular structure of compound 2 and its crystal packing were determined by single crystal X-ray diffraction. The nitrate anions are also involved in intermolecular hydrogen bonding with adjacent ferrocene units and it forms zig-zag one-dimensional polymeric structure. UV-Vis investigations on the positive solvatochromic behavior of 1-3 revealed that the solvation of the push-pull character increases with increasing polarity. The third-order nonlinear optical (NLO) properties of 1-3 have been determined by Z-scan technique and the results indicate that compounds 1-3 exhibits the strong self-defocusing effect. The nonlinear susceptibility χ(3) values are calculated in the order of 10-6 esu.
Nirosha, M; Kalainathan, S; Sarveswari, S; Vijayakumar, V; Srikanth, A
2015-02-25
Single crystal of 1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone was grown using slow evaporation solution growth technique. Single crystal X-ray diffraction study reveals the lattice parameters of the grown crystal. The modes of vibration of different molecular groups present in 2M6NQE were identified by FTIR spectral analysis. Its optical behavior was examined through UV-vis-NIR absorption and PL emission spectrum. They signify that the crystal has transparency in the region between 383 and 1100 nm. The PL spectrum of the title compound shows green emission in the crystal. From the thermal analysis, 2M6NQE has found to be thermally stable up to 263°C, and the melting point of the material is 170°C. The estimations of third order non-linear optical properties like non-linear absorption coefficient (β), non-linear refractive index (n2) and susceptibility [χ(3)] were calculated using Z-scan technique. It has observed that, crystal exhibits reverse saturation absorption and self-defocusing performance. Etching study was carried out for the grown crystal using different solvents. Copyright © 2014 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Thirupugalmani, K.; Karthick, S.; Shanmugam, G.; Kannan, V.; Sridhar, B.; Nehru, K.; Brahadeeswaran, S.
2015-11-01
The title compound, 2-amino-4-picolinium-nitrophenolate-nitrophenol (2A4PNN), has been synthesized and optical quality single crystals of 2A4PNN were grown by solution growth technique. The crystal structure was solved by single crystal X-ray diffraction method. The 2A4PNN molecule was found to possess intermolecular herringbone structure and to crystallize in orthorhombic crystal system with a noncentrosymmetric space group of Pna21 (Point group mm2). The functional groups of 2A4PNN were confirmed through FT-IR and Raman vibrational spectroscopic studies and NMR spectrum was recorded to study its molecular structure. The UV-Vis and photoluminescence spectra were recorded to explore its optical transmittance and emission properties respectively. The SHG efficiency and phasematchability were investigated through Kurtz and Perry powder technique using sieved/graded powders derived from polycrystals of 2A4PNN. The laser damage threshold studies of 2A4PNN single crystal were performed on (1 0 0) plane using a pulsed Nd:YAG laser (1064 nm). The third-order optical properties of 2A4PNN single crystal were measured by Z-scan technique. In addition, the quantum chemical studies were performed on the isolated 2A4PNN molecule using density functional theory (DFT) calculations at the B3LYP/6-311++G (d, p) basis set.
1984-02-01
proerm witi three ina added to it for geeration of the mueamdn of tho the em tem doadom Wee. CCI’ % ud he dowo Z domsan veruloms, CWVUN sad CIILL The m...THIRD ORDER BUTTERWORTH FILTER USING IMPLEMENTATIONS DERIVED FROM BOTH Z AND S DOMAIN REPRESENTATIONS get Edvard E. L. Mitchell Mitchell and Gauthier...S. TYPE OF REPORT & PERIOD COVERED ACSL SIMULATION OF A THIRD ORDER BUTTERWORTH FILTER USING IMPLEMENTATIONS DERIVED FROM BOTH Z AND S DOMAIN
Analytic energy gradients for the orbital-optimized third-order Møller-Plesset perturbation theory
NASA Astrophysics Data System (ADS)
Bozkaya, Uǧur
2013-09-01
Analytic energy gradients for the orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) [U. Bozkaya, J. Chem. Phys. 135, 224103 (2011)], 10.1063/1.3665134 are presented. The OMP3 method is applied to problematic chemical systems with challenging electronic structures. The performance of the OMP3 method is compared with those of canonical second-order Møller-Plesset perturbation theory (MP2), third-order Møller-Plesset perturbation theory (MP3), coupled-cluster singles and doubles (CCSD), and coupled-cluster singles and doubles with perturbative triples [CCSD(T)] for investigating equilibrium geometries, vibrational frequencies, and open-shell reaction energies. For bond lengths, the performance of OMP3 is in between those of MP3 and CCSD. For harmonic vibrational frequencies, the OMP3 method significantly eliminates the singularities arising from the abnormal response contributions observed for MP3 in case of symmetry-breaking problems, and provides noticeably improved vibrational frequencies for open-shell molecules. For open-shell reaction energies, OMP3 exhibits a better performance than MP3 and CCSD as in case of barrier heights and radical stabilization energies. As discussed in previous studies, the OMP3 method is several times faster than CCSD in energy computations. Further, in analytic gradient computations for the CCSD method one needs to solve λ-amplitude equations, however for OMP3 one does not since λ _{ab}^{ij(1)} = t_{ij}^{ab(1)} and λ _{ab}^{ij(2)} = t_{ij}^{ab(2)}. Additionally, one needs to solve orbital Z-vector equations for CCSD, but for OMP3 orbital response contributions are zero owing to the stationary property of OMP3. Overall, for analytic gradient computations the OMP3 method is several times less expensive than CCSD (roughly ˜4-6 times). Considering the balance of computational cost and accuracy we conclude that the OMP3 method emerges as a very useful tool for the study of electronically challenging chemical
Analytic energy gradients for the orbital-optimized third-order Møller-Plesset perturbation theory.
Bozkaya, Uğur
2013-09-14
Analytic energy gradients for the orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) [U. Bozkaya, J. Chem. Phys. 135, 224103 (2011)] are presented. The OMP3 method is applied to problematic chemical systems with challenging electronic structures. The performance of the OMP3 method is compared with those of canonical second-order Møller-Plesset perturbation theory (MP2), third-order Møller-Plesset perturbation theory (MP3), coupled-cluster singles and doubles (CCSD), and coupled-cluster singles and doubles with perturbative triples [CCSD(T)] for investigating equilibrium geometries, vibrational frequencies, and open-shell reaction energies. For bond lengths, the performance of OMP3 is in between those of MP3 and CCSD. For harmonic vibrational frequencies, the OMP3 method significantly eliminates the singularities arising from the abnormal response contributions observed for MP3 in case of symmetry-breaking problems, and provides noticeably improved vibrational frequencies for open-shell molecules. For open-shell reaction energies, OMP3 exhibits a better performance than MP3 and CCSD as in case of barrier heights and radical stabilization energies. As discussed in previous studies, the OMP3 method is several times faster than CCSD in energy computations. Further, in analytic gradient computations for the CCSD method one needs to solve λ-amplitude equations, however for OMP3 one does not since λ(ab)(ij(1))=t(ij)(ab(1)) and λ(ab)(ij(2))=t(ij)(ab(2)). Additionally, one needs to solve orbital Z-vector equations for CCSD, but for OMP3 orbital response contributions are zero owing to the stationary property of OMP3. Overall, for analytic gradient computations the OMP3 method is several times less expensive than CCSD (roughly ~4-6 times). Considering the balance of computational cost and accuracy we conclude that the OMP3 method emerges as a very useful tool for the study of electronically challenging chemical systems.
Yu, J. M.; Balbuena, P. B.; Budzien, J. L.; Leung, Kevin
2011-02-22
We applied static and dynamic hybrid functional density functional theory (DFT) calculations to study the interactions of one and two excess electrons with ethylene carbonate (EC) liquid and clusters. Optimal structures of (EC)_{n} and (EC)_{n}^{-} clusters devoid of Li_{+} ions, n = 1–6, were obtained. The excess electron was found to be localized on a single EC in all cases, and the EC dimeric radical anion exhibits a reduced barrier associated with the breaking of the ethylene carbon–oxygen covalent bond compared to EC_{-}. In ab initio molecular dynamics (AIMD) simulations of EC_{-} solvated in liquid EC, large fluctuations in the carbonyl carbon–oxygen bond lengths were observed. AIMD simulations of a two-electron attack on EC in EC liquid and on Li metal surfaces yielded products similar to those predicted using nonhybrid DFT functionals, except that CO release did not occur for all attempted initial configurations in the liquid state.
NASA Astrophysics Data System (ADS)
Chen, Xueli; Sun, Fangfang; Yang, Defu; Liang, Jimin
2015-09-01
For fluorescence tomographic imaging of small animals, the liver is usually regarded as a low-scattering tissue and is surrounded by adipose, kidneys, and heart, all of which have a high scattering property. This leads to a breakdown of the diffusion equation (DE)-based reconstruction method as well as a heavy computational burden for the simplified spherical harmonics equation (SPN). Coupling the SPN and DE provides a perfect balance between the imaging accuracy and computational burden. The coupled third-order SPN and DE (CSDE)-based reconstruction method is developed for fluorescence tomographic imaging. This is achieved by doubly using the CSDE for the excitation and emission processes of the fluorescence propagation. At the same time, the finite-element method and hybrid multilevel regularization strategy are incorporated in inverse reconstruction. The CSDE-based reconstruction method is first demonstrated with a digital mouse-based liver cancer simulation, which reveals superior performance compared with the SPN and DE-based methods. It is more accurate than the DE-based method and has lesser computational burden than the SPN-based method. The feasibility of the proposed approach in applications of in vivo studies is also illustrated with a liver cancer mouse-based in situ experiment, revealing its potential application in whole-body imaging of small animals.
Chen, Xueli; Sun, Fangfang; Yang, Defu; Liang, Jimin
2015-01-01
For fluorescence tomographic imaging of small animals, the liver is usually regarded as a low-scattering tissue and is surrounded by adipose, kidneys, and heart, all of which have a high scattering property. This leads to a breakdown of the diffusion equation (DE)–based reconstruction method as well as a heavy computational burden for the simplified spherical harmonics equation (SP(N)). Coupling the SP(N) and DE provides a perfect balance between the imaging accuracy and computational burden. The coupled third-order SPN and DE (CSDE)-based reconstruction method is developed for fluorescence tomographic imaging. This is achieved by doubly using the CSDE for the excitation and emission processes of the fluorescence propagation. At the same time, the finite-element method and hybrid multilevel regularization strategy are incorporated in inverse reconstruction. The CSDE-based reconstruction method is first demonstrated with a digital mouse-based liver cancer simulation, which reveals superior performance compared with the SPN and DE-based methods. It is more accurate than the DE-based method and has lesser computational burden than the SPN-based method. The feasibility of the proposed approach in applications of in vivo studies is also illustrated with a liver cancer mouse-based in situ experiment, revealing its potential application in whole-body imaging of small animals.
Vinogradova, I M; Zajicek, J; Gentile, S; Brown, E R
2002-05-31
Intracellular microelectrode recordings were made from presynaptic and postsynaptic regions of the third order giant synapses of the squids Alloteuthis subulata and Loligo vulgaris. Synaptically generated postsynaptic action potential trains, and excitatory postsynaptic potentials (EPSPs) were reversibly decreased by glycine, beta - alanine or taurine while presynaptic action potentials (APs) were unaltered. Glycine was effective in the presence of strychnine (30-50 microM), NMDA (500 microM), AP-5 (50 microM), CPP (100 microM), or MK 801 (which also had no effect on normal synaptic transmission). The glycine effect was reduced reversibly by D-tubocurarine (100 microM) and blocked by reducing extracellular chloride by 50% with propionate. Excitatory postsynaptic currents (EPSCs) were decreased by glycine addition without altering resting membrane conductance. We postulate that glycine or a glycine like substance provides an excitatory postsynaptic input during synaptic stimulation. Bath addition of glycine desensitises these receptors and decreases the amplitude of the EPSPs and EPSCs. Modulation of this synaptic input may provide an effective mechanism to suppress or potentiate synaptic transmission in the squid giant synapse.
NASA Astrophysics Data System (ADS)
García-Merino, J. A.; Mercado-Zúñiga, C.; Martínez-González, C. L.; Torres-SanMiguel, C. R.; Vargas-García, J. R.; Torres-Torres, C.
2017-03-01
The influence of a magnetic field on electrical conductivity and the third-order nonlinear optical properties exhibited by carbon nanotubes decorated with platinum nanoparticles is reported. The experimental and numerical results of the nonlinear magneto-optics, magneto-conductivity and photo-thermal processes were analyzed. The simultaneous impact of optical absorptive nonlinearities and the magnetic field in the sample allowed us to encrypt information in the electronic signals by designing an exclusive-OR logic gate scheme. The samples were prepared in film form using a spray pyrolysis route and a chemical vapor deposition approach. The characterization of the morphological nature of the multiwall nanotubes was evaluated by transmission electron microscopy and x-ray techniques. A vectorial two-wave mixing method was conducted by using nanosecond pulses at 532 nm in order to estimate the nonlinear optical behavior in the nanohybrid materials explored. An important enhancement in the phonon-band-structured transport from the inclusion of nanoparticles in the nanotubes was numerically calculated. A distinguished modification in the transient dynamics of the photo-thermal transitions and Kerr nonlinearities was pointed out to be due to the metallic nanoparticles incorporated in the sample. An extraordinary evolution of the magneto-conductivity, together with a strong change in the optical Kerr transmittance exposed to the magnetic field in propagation through the nanostructures, was observed.
Second- and Third-Order Elastic Constants of Filaments of HexTow® IM7 Carbon Fiber
NASA Astrophysics Data System (ADS)
Oliveira, L.; Hitchcock, D.; Behlow, H.; Podila, R.; Skove, M. J.; Serkiz, S. M.; Rao, A. M.
2014-03-01
Single filaments of HexTow® IM7-12K carbon fiber were subjected to tensile measurements on a device which applies a known stress σ, and measures the resulting strain ɛ, and the change in resistivity Δρ. Young's modulus E, the resistivity ρ, the piezoresistivity Δρ/ρɛ, and the nonlinearity in the stress-strain relation δ, were determined to be 264.1 ± 16.0 GPa, 1.5 ± 0.1 × 10-3 Ω cm, 1.3 ± 0.1, and -4.96 ± 0.23, respectively. The values obtained for Young's modulus and the resistivity of the fiber are in reasonable agreement with the values reported by the manufacturer. To the best of our knowledge, this is the first report of a measurement of a third-order elastic constant of a single filament of HexTow® IM7-12K. Given the high elastic strains attainable in these fibers and the negative value of δ, the usual calculation of E from a linear fit to the stress-strain data leads to an incorrect higher value of E. According to the accepted thermodynamic definition of the elastic constants, one must use the initial slope of the stress-strain curve to evaluate E. We also observed that the glue used to secure the fiber has an influence on the apparent modulus of the fiber.
NASA Astrophysics Data System (ADS)
Hättig, Christof; Tew, David P.; Helmich, Benjamin
2012-05-01
We present an algorithm for computing explicitly correlated second- and third-order Møller-Plesset energies near the basis set limit for large molecules with a cost that scales formally as N^4 with system size N. This is achieved through a hybrid approach where locality is exploited first through orbital specific virtuals (OSVs) and subsequently through pair natural orbitals (PNOs) and integrals are approximated using density fitting. Our method combines the low orbital transformation costs of the OSVs with the compactness of the PNO representation of the doubles amplitude vector. The N^4 scaling does not rely upon the a priori definition of domains, enforced truncation of pair lists, or even screening and the energies converge smoothly to the canonical values with decreasing occupation number thresholds, used in the selection of the PNO basis. For MP2.5 intermolecular interaction energies, we find that 99% of benchmark basis set limit correlation energy contributions are recovered using an aug-cc-pVTZ basis and that on average only 50 PNOs are required to correlate the significant orbital pairs.
Hättig, Christof; Tew, David P; Helmich, Benjamin
2012-05-28
We present an algorithm for computing explicitly correlated second- and third-order Møller-Plesset energies near the basis set limit for large molecules with a cost that scales formally as N(4) with system size N. This is achieved through a hybrid approach where locality is exploited first through orbital specific virtuals (OSVs) and subsequently through pair natural orbitals (PNOs) and integrals are approximated using density fitting. Our method combines the low orbital transformation costs of the OSVs with the compactness of the PNO representation of the doubles amplitude vector. The N(4) scaling does not rely upon the a priori definition of domains, enforced truncation of pair lists, or even screening and the energies converge smoothly to the canonical values with decreasing occupation number thresholds, used in the selection of the PNO basis. For MP2.5 intermolecular interaction energies, we find that 99% of benchmark basis set limit correlation energy contributions are recovered using an aug-cc-pVTZ basis and that on average only 50 PNOs are required to correlate the significant orbital pairs.
NASA Astrophysics Data System (ADS)
Htwe, Zin Maung; Zhang, Yun-Dong; Yao, Cheng-Bao; Li, Hui; Yuan, Ping
2017-04-01
Aluminum doped zinc oxide (AZO) thin films were fabricated by simultaneous RF/DC magnetron sputtering technique on sapphire (Al2O3) substrate with different DC sputtering power 2, 6, 8 and 10 W respectively. The sputtered thin films were annealed at 350 °C in order to improve the crystal quality. AZO thin films are systematically analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-VIS spectrometer for structural and optical properties. XRD patterns show that all sputtered thin films are well crystallized with hexagonal wurtzite structure. SEM images reveal the average crystallite sizes are increased after doping Al in ZnO which agreed with the calculated values from XRD. All thin films possess high optical transmittance in visible region and optical band gap values are relatively increased with Al concentration. The ultrafast transient absorption (TA) of AZO was analyzed by femtosecond pump-probe spectroscopy. The kinetic TA curves were fitted by tri-exponential decay function and obtained decay time constants are found to be in few picosecond and nanosecond range for ultrafast and slow processes respectively. Third order nonlinear optical absorption and refraction coefficients were investigated by using Z-scan technique. The observed nonlinear coefficients are enhanced with Al concentration in ZnO.
NASA Astrophysics Data System (ADS)
Mao, L.; Andreoli, A.; Comiti, F.; Lenzi, M. A.; Iturraspe, R.; Burns, S.; Novillo, M. G.
2007-05-01
Dead wood pieces, especially when organized in jams, play an important geomorphic role in streams because of the effects on flow hydraulics, pool formation and sediments storage. The increase of stream morphological diversity and complexity also exerts also an important ecological role. This work reports on geomorphic role of large wood pieces and jams in a third order mountain stream located in the Southern Tierra del Fuego (Argentina), and draining an old-growth nothofagus forested basin not influenced by the beavers damming activity. Even if the in-stream number of wood pieces (length > 1m; diameter > 0.1 m) is comparable to what observed in other climatic areas, the slow growth of the nothofagus forest causes a lower wood abundance in terms of volumetric load. Since the relatively small dimensions of the surveyed large wood pieces, almost the 70% of them demonstrated to have been fluvial transported and the also wood jams reflect the apparent dynamic of wood in the channel. Wood jams exert a significant influence on the channel morphology, representing almost the half of the drop caused by steps and being responsible for the creation of 30% of the pools. The LW-forced pool volume is strongly and positively correlated to the height of the LW jam, and a significant inverse relationship between pool spacing and wood density within is evident if only the LW-forced pools are considered. The geomorphic influence of LW jams is also exerted by a considerable sediment storing capacity.
NASA Astrophysics Data System (ADS)
Sabari Girisun, T. C.; Saravanan, M.; Vinitha, G.
2017-03-01
Single crystalline nanoclusters and nanorods like structure of barium borate (β- BaB2O4) were synthesized by organic free hydrothermal method at various reaction times of 8, 24 and 48 h. XRD shows the formation of pure and single phase of β- BaB2O4 with improved crystallinity at elevated reaction time. β- BaB2O4 crystallizes in hexagonal system with lattice parameter a=b=12.53 Å and c=12.72 Å. The surface morphology picturizes the formation of nanoclusters and rod structures with several micrometer length and nanometer diameter. By increasing the reaction time and due to prolonged pressure, aggregation followed by elongation resulted in the transformation of nanoclusters into rod like structure. The nanostructured barium borates possess strong UV absorbance and wide optical window. The nonlinear optical studies by Z- scan technique shows the material to possess saturable absorption and self-defocusing nature. A strong variation in third order nonlinear optical parameters with change in the morphology of β- BaB2O4 was observed. Also β- BaB2O4 rod like structure is identified to be more efficient optical limiters in the green regime of continuous wave lasers.
NASA Astrophysics Data System (ADS)
Muruganandi, G.; Saravanan, M.; Vinitha, G.; Jessie Raj, M. B.; Sabari Girisun, T. C.
2017-05-01
Reduced graphene oxide (rGO) was prepared by reduction method using various reductants like hydrazine, sodium borohydride and ascorbic acid. XRD and Raman analysis confirmed the effective removal of functional groups in GO. SEM revealed that rGO consists of thin crumpled and disordered sheets closely associated with each other. Blue shift in UV-absorption maxima was due to weak interlayer coupling between the layers of rGO. Third order NLO properties of dispersed rGO were measured by Z-scan technique (532 nm, 50 mW). Both GO and rGO possess self defocusing, saturable absorption and optical limiting behavior. The nonlinear component of refractive index, absorption coefficient and optical susceptibility were found to be 10-8 cm2/W, 10-3 cm/W and 10-6 esu respectively. Tunability of NLO coefficients with altering functional groups upon rGO was achieved. rGO prepared using hydrazine with high NLO coefficient and excellent durability, signify the scope of utilizing them as optical limiters.
Chen, Feifei; Cheng, Junwen; Dai, Shixun; Xu, Zhe; Ji, Wei; Tan, Ruiqin; Zhang, Qinyuan
2014-06-02
Large and ultrafast third-order optical nonlinearities in Ag-doped bismuthate glasses which are prepared by incorporating Ag ions into bismuthate glasses to form Ag nanoparticles through a consecutive melting-quenching-annealing technique are reported. Due to the high refractive index of bismuthate glass, surface plasmon resonance (SPR) of Ag nanoparticles is extendable to 1400 nm, resulting in a higher nonlinear refractive index than bismuthate glass. Femtosecond Z-scans show that the nonlinear refractive index, as high as 9.4 × 10(-17) and 5.6 × 10(-18) m(2) W(-1) at 800 and 1300 nm, respectively, can be achieved by selecting an optimized concentration of Ag nano-sized particles. And two-photon absorption at 800 nm is suppressed due to a blue shift in the band-gap of Ag-doped bismuthate glasses, as compared to pristine bismuthate glasses. Optical Kerr shutter technique reveals that these nonlinearities have a relaxation time of < 1 ps.
Third-order random lasing via Raman gain and Rayleigh feedback within a half-open cavity.
Wang, Zinan; Wu, Han; Fan, Mengqiu; Rao, Yunjiang; Jia, Xinhong; Zhang, Weili
2013-08-26
Third-order random lasing operating in 1670 nm spectral band is experimentally demonstrated for the first time to the best of our knowledge, with only 2.45 W pump threshold. The lasing cavity is formed by G.652 fiber and fiber loop mirrors (FLMs), while the former acts as the distributed reflector and the latter acts as the point reflector. The G.652 fiber and the FLMs are connected via a multi-band wavelength-division-multiplexer, which ensures each of the three Raman Stokes components generated in the long fiber is routed to one FLM and then reflected back with minimum loss. Unlike existing half-open random lasing cavities using fiber Bragg gratings, the reflection bandwidth of FLMs is wide enough to preserve the intrinsic spectral features of each lasing bands, providing a valuable platform to study the mechanism of high-order random lasing in fibers. Also, the reflection efficiency can be treated as an invariant as the pump power grows, significantly reducing the threshold of high-order random lasing. The stationary model is used to calculate the output power, and the results fit the experimental data well.
NASA Technical Reports Server (NTRS)
Cheng, A.; Xu, K.-M.; Golaz, J.-C.
2004-01-01
A hierarchy of third-order turbulence closure models are used to simulate boundary-layer cumuli in this study. An unrealistically strong liquid-water oscillation (LWO) is found in the fully prognostic model, which predicts all third moments. The LWO propagates from cloud base to cloud top with a speed of 1 m/s. The period of the oscillation is about 1000 s. Liquid-water buoyancy terms in the third-moment equations contribute to the LWO. The LWO mainly affects the vertical profiles of cloud fraction, mean liquid-water mixing ratio and the fluxes of liquid-water potential temperature and total water, but has less impact on the vertical profiles of other second-moments and third-moments. In order to minimize the LWO, a moderate large diffusion coefficient and a large turbulent dissipation at its originating level are needed. However, this approach distorts the vertical distributions of cloud fraction and liquid-water mixing ratio. A better approach is to parameterize liquid-water buoyancy more reasonably. A minimally prognostic model, which diagnoses all third moments except for vertical velocity, is shown to produce better results, compared to a fully prognostic model.
NASA Astrophysics Data System (ADS)
Gong, Weixiang; Yang, Junyi; Qin, Yuan-cheng; Wu, Xing-zhi; Jin, Xiao; Song, Yinglin
2016-10-01
The third-order nonlinear optical properties of benzothiadiazole copolymer with triphenylamine derivative side chain (BCT) dissolved in chloroform are investigated by top-hat Z-scan and time-resolved pump-probe techniques with a picoseconds pulses laser at wavelength of 532nm. Organic polymers of triphenylamine have been widely applied to optoelectronic devices owing to its outstanding physics and chemistry characteristic. So its nonlinear optical characteristic is worth studying. The sample's excited-state dynamics can be detected by the pump-probe with phase object device with/without an aperture in the far field. We can determine the sample's nonlinear absorptive and refractive coefficient by the top-hot Z-scan device with/without an aperture in the far field. The experimental results show that the BCT has a good reverse saturation absorption and negative refraction. At the same time, the BCT showed up long excited-state lifetimes. By means of a five-level model and analyzing the experimental curves, all nonlinear optical parameters are obtained. With the proper lifetime and intersystem crossing time, this sample can be a candidate for optical limiting.
NASA Technical Reports Server (NTRS)
Cheng, A.; Xu, K.-M.; Golaz, J.-C.
2004-01-01
A hierarchy of third-order turbulence closure models are used to simulate boundary-layer cumuli in this study. An unrealistically strong liquid-water oscillation (LWO) is found in the fully prognostic model, which predicts all third moments. The LWO propagates from cloud base to cloud top with a speed of 1 m/s. The period of the oscillation is about 1000 s. Liquid-water buoyancy terms in the third-moment equations contribute to the LWO. The LWO mainly affects the vertical profiles of cloud fraction, mean liquid-water mixing ratio and the fluxes of liquid-water potential temperature and total water, but has less impact on the vertical profiles of other second-moments and third-moments. In order to minimize the LWO, a moderate large diffusion coefficient and a large turbulent dissipation at its originating level are needed. However, this approach distorts the vertical distributions of cloud fraction and liquid-water mixing ratio. A better approach is to parameterize liquid-water buoyancy more reasonably. A minimally prognostic model, which diagnoses all third moments except for vertical velocity, is shown to produce better results, compared to a fully prognostic model.
Self-oscillations of a third order PLL in periodic and chaotic mode and its tracking in a slave PLL
NASA Astrophysics Data System (ADS)
Sarkar, B. C.; Chakraborty, S.
2014-03-01
The dynamics of a third order phase locked loop (PLL) with a resonant low pass filter (LPF) has been studied numerically in the parameter space of the system. The range of stable synchronous operating zone of the PLL, expressed in terms of system and signal parameters, is estimated. The obtained results are in agreement with the analytically predicted results in the literature. The PLL dynamics in the unstable region is found to have a sequence of period doubling bifurcation and chaos. In the master-slave mode of operation of two 3rd order PLLs, the slave PLL can track the periodic as well as chaotic dynamics of the master PLL for a narrow range of effective frequency offset when other design parameters are within the stable zone as predicted for an isolated PLL. The synchronization of the master and slave PLLs in this condition is proved to be a generalized one using the auxiliary slave system approach. Experimental observations on prototype hardware circuits for an isolated PLL and for a master-slave PLL arrangement are also given.
NASA Astrophysics Data System (ADS)
Kengne, J.; Njitacke Tabekoueng, Z.; Fotsin, H. B.
2016-07-01
We perform a systematic analysis of a system consisting of an autonomous third order Duffing-Holmes type chaotic oscillator recently introduced by Tamasevicius et al. (2009). In this type of oscillators, the symmetrical characteristics of the nonlinear component necessary for generating chaotic oscillations is synthesized by using a pair of semiconductor diodes connected in anti-parallel. Based on the Shockley diode equation and a judicious choice of state variables, we derive a smooth mathematical model (involving hyperbolic sine and cosine functions) for a better description of both the regular and chaotic dynamics of the oscillator. The bifurcation analysis shows that chaos is achieved via the classical period-doubling and symmetry restoring crisis scenarios. More interestingly, some regions of the parameter space corresponding to the coexistence of multiple attractors (e.g. coexistence of four different attractors for the same values of system parameters) are discovered. This striking phenomenon is unique and has not yet been reported previously in an electrical circuit (the universal Chua's circuit included, in spite the immense amount of related research work), and thus represents a meaningful contribution to the understanding of the behavior of nonlinear dynamical systems in general. Some PSpice simulations of the nonlinear dynamics of the oscillator are carried out to verify the theoretical analysis.
Yuan, Kai-Jun; Bandrauk, Andre D.
2011-06-15
Molecular high-order harmonic generation (MHOHG) by a combined intense circularly polarized laser pulse and static electric field has been studied from the appropriate time-dependent Schroedinger equation (TDSE) for the H{sub 2}{sup +} molecular ion. It is found that for a particular static field strength derived from a classical model, efficient MHOHG spectra are obtained with maximum energy I{sub p} + 9.05U{sub p}, where I{sub p} is the ionization potential and U{sub p}=E{sub 0}{sup 2}/4m{sub e{omega}0}{sup 2} is the ponderomotive energy at amplitude E{sub 0} and frequency {omega}{sub 0} of the circularly polarized laser pulse. The static field controls recollision of the electron with parent ions and is confirmed by numerical solutions of the H{sub 2}{sup +} TDSE at equilibrium. To produce circularly polarized MHOHG spectra, a combination of an elliptically polarized pulse and a static electric field is found to be most efficient. A time-frequency analysis obtained via Gabor transforms is employed to identify electron recollision times responsible for the generation of these high-order harmonics. It is found that only single recollision trajectories contribute to the circularly polarized harmonics, thus generating new sources for high-frequency circularly polarized attosecond pulses.
Chella, F; Marzetti, L; Pizzella, V; Zappasodi, F; Nolte, G
2014-05-01
We present a novel approach to the third order spectral analysis, commonly called bispectral analysis, of electroencephalographic (EEG) and magnetoencephalographic (MEG) data for studying cross-frequency functional brain connectivity. The main obstacle in estimating functional connectivity from EEG and MEG measurements lies in the signals being a largely unknown mixture of the activities of the underlying brain sources. This often constitutes a severe confounder and heavily affects the detection of brain source interactions. To overcome this problem, we previously developed metrics based on the properties of the imaginary part of coherency. Here, we generalize these properties from the linear to the nonlinear case. Specifically, we propose a metric based on an antisymmetric combination of cross-bispectra, which we demonstrate to be robust to mixing artifacts. Moreover, our metric provides complex-valued quantities that give the opportunity to study phase relationships between brain sources. The effectiveness of the method is first demonstrated on simulated EEG data. The proposed approach shows a reduced sensitivity to mixing artifacts when compared with a traditional bispectral metric. It also exhibits a better performance in extracting phase relationships between sources than the imaginary part of the cross-spectrum for delayed interactions. The method is then applied to real EEG data recorded during resting state. A cross-frequency interaction is observed between brain sources at 10Hz and 20Hz, i.e., for alpha and beta rhythms. This interaction is then projected from signal to source level by using a fit-based procedure. This approach highlights a 10-20Hz dominant interaction localized in an occipito-parieto-central network.
NASA Astrophysics Data System (ADS)
Pichan, Karuppasamy; Muthu, Senthil Pandian; Perumalsamy, Ramasamy
2017-09-01
The organic single crystal of piperazinium bis(4-hydroxybenzenesulphonate) (P4HBS) was grown by slow evaporation solution technique (SEST) at room temperature. The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. Functional groups of P4HBS crystal were confirmed by FTIR spectrum analysis. The optical quality of the grown crystal was identified by the UV-Vis NIR spectrum analysis. The grown crystal has good optical transmittance in the range of 410-1100 nm. In photoluminescence spectrum, sharp emission peaks are observed, which indicates the ultraviolet (UV) emission. The photoconductivity study reveals that the grown crystal has negative photoconductive nature. The thermal behaviour of the P4HBS crystal was investigated by thermogravimetric and differential thermal analysis (TG-DTA). The mechanical stability of grown crystal was analyzed and the indentation size effect (ISE) was explained by Hays-Kendall's (HK) approach and proportional specimen resistance model (PSRM). Chemical etching study was carried out and the etch pit density (EPD) was calculated. The dielectric constant (ε‧) and dielectric loss (tan δ) as a function of frequency were measured for the grown crystal. The solid state parameters such as valence electron, plasma energy, Penn gap and Fermi energy were evaluated theoretically for the P4HBS using the empirical relation. The estimated values are used to calculate the electronic polarizability. The third-order nonlinear optical properties such as nonlinear refractive index (n2), absorption co-efficient (β) and susceptibility (χ(3)) were studied by Z-scan technique at 632.8 nm using He-Ne laser.
Time-dependent fifth-order bands in nominally third-order 2D IR vibrational echo spectra.
Thielges, Megan C; Fayer, Michael D
2011-09-01
Progress in the field of 2D IR vibrational spectroscopy has been bolstered by the production of intense mid-IR laser pulses. As higher-energy pulses are employed, a concomitant increase occurs in the likelihood of fifth-order contributions to the 2D IR spectra. We report the appearance of fifth-order signals in 2D IR spectra of CO bound to the active site of the enzyme cytochrome P450(cam) with the substrate norcamphor. Two bands with novel time dependences, one on the diagonal and one off-diagonal, are not accounted for by normal third-order interactions. These bands are associated with a ν = 1-2 vibrational transition frequency. Both bands decay to 0 and then grow back in with opposite sign. The diagonal band is positive at short time, decays to 0, reappears with negative sign, before eventually decaying to 0. The off-diagonal band is negative at short time, decays to 0, reappears positive, and then decays to 0. The appearance and time dependence of these bands are characterized. Understanding these fifth-order bands is useful because they may be misidentified with time-dependent bands that arise from other processes, such as chemical exchange, vibrational coupling, or energy transfer. The presence and unusual time dependences of the fifth-order bands are reproduced with model calculations that account for the fact that vibrational relaxation from the ν = 2 to 1 level is approximately a factor of 2 faster than that from the ν = 1 to 0 level. © 2011 American Chemical Society
Chella, F.; Marzetti, L.; Pizzella, V.; Zappasodi, F.; Nolte, G.
2014-01-01
We present a novel approach to the third order spectral analysis, commonly called bispectral analysis, of electroencephalographic (EEG) and magnetoencephalographic (MEG) data for studying cross-frequency functional brain connectivity. The main obstacle in estimating functional connectivity from EEG and MEG measurements lies in the signals being a largely unknown mixture of the activities of the underlying brain sources. This often constitutes a severe confounder and heavily affects the detection of brain source interactions. To overcome this problem, we previously developed metrics based on the properties of the imaginary part of coherency. Here, we generalize these properties from the linear to the nonlinear case. Specifically, we propose a metric based on an antisymmetric combination of cross-bispectra, which we demonstrate to be robust to mixing artifacts. Moreover, our metric provides complex-valued quantities that give the opportunity to study phase relationships between brain sources. The effectiveness of the method is first demonstrated on simulated EEG data. The proposed approach shows a reduced sensitivity to mixing artifacts when compared with a traditional bispectral metric. It also exhibits a better performance in extracting phase relationships between sources than the imaginary part of cross-spectrum for delayed interactions. The method is then applied to real EEG data recorded during resting state. A cross-frequency interaction is observed between brain sources at 10 Hz and 20 Hz, i.e., for alpha and beta rhythms. This interaction is then projected from signal to source level by using a fit-based procedure. This approach highlights a 10–20 Hz dominant interaction localized in an occipito-parieto-central network. PMID:24418509
NASA Astrophysics Data System (ADS)
Makhal, Krishnandu; Mathur, Paresh; Maurya, Sidharth; Goswami, Debabrata
2017-02-01
Third order nonlinearities of Mn(III)-Phthalocyanine chloride in dimethyl-sulphoxide under 50 fs pulses, operating at 94 MHz, by eliminating cumulative thermal effects have been investigated and reported by us. Modifications were done in data acquisition during Z-scan experiment, which included recording of time evolution waveform traces in an oscilloscope and not collection of Z versus transmission and utilization of a chopper of a suitable duty cycle. Time evolution traces were further processed analytically through MatLab® programming, which yielded Z-scan traces similar to what was obtained with single shot 50 fs pulse. We observed reverse saturable absorption at 800 nm owing to excited state absorption. We show that the nonlinear refractive index (γ) and nonlinear absorption coefficient (β) are over estimated almost 100 times, when MHz pulses are used compared to a situation, where thermo-optical nonlinearities are accounted. Illumination and dark periods are carefully set in a way, so that the sample is able to completely recover its initial temperature before arrival of the next pulse. Magnitudes of γ and β were found to be -(6.5-4.9) × 10-16 m2/W and (5.4-6.2) × 10-10 m/W under the MHz condition, whereas they were -(0.18-2.2) × 10-18 m2/W and (9.5-15) × 10-12 m/W under the thermally managed condition, respectively. To reveal the associated fast nonlinearity, femtosecond transient absorption experiment was performed, which inferred excited state absorption and ground state bleaching across the 450-780 nm region. Dynamics associated with these processes are reported along with fluorescence lifetime obtained through the TCSPC technique. Structure optimization using TDDFT calculations and HOMO-LUMO gaps with orbital pictures are also shown.
Yan, Ling; Zhao, Ying; Han, Cui-xiang; Tong, Xiao-li
2007-11-01
By placing 5 mm- and 0.1 mm mesh bags with Dracontomelon duperreanum (Anacardiaceae) and Syzygium jambos (Myrtaceae) litters in the Hengshishui Stream, a third-order stream in northern Guangdong of China, this paper studied the decomposition of the litters and the colonization of macro-invertebrates over a 101-day period. The results showed that the decomposition rate of D. duperreanum litter in 5 mm- and 0.1 mm mesh bags was 0.0247 d(-1) and 0.0151 d(-1), while that of S. jambos litter was 0.0108 d(-1) and 0.0095 d(-1), respectively, indicating that D. duperreanum litter decomposed faster than S. jambos litter, and the decomposition rates of these two kinds of litters were higher in coarse mesh bag than in fine mesh bag. Among the colonized macro-invertebrate functional feeding groups, scraper occupied the highest proportion (36%), followed by collector (33%), predator (25%), and shredder (6%). At the middle and late stages of the experiment, the total number of individuals and the numbers and densities of dominant groups of macroinvertebrates on D. duperreanum litter were significantly higher than those on S. jambos litter. It was suggested that in the subtropical medium-size streams where shredders are few or absent, scrapers play an important role in the breakdown of litter. The low decomposition rate of S. jambos litter was mainly due to its high content of polyphenols which inhibits microbial activity and makes the litter less eatable to the macro-invertebrates.
1.55μm laterally coupled ridge-waveguide DFB lasers with third-order surface grating
NASA Astrophysics Data System (ADS)
Dridi, Kais; Benhsaien, Abdessamad; Zhang, Jessica; Hall, Trevor
2012-10-01
Laterally-coupled distributed feedback (LC-DFB) lasers offer compelling advantages over standard DFB lasers. The use of surface grating on the ridge waveguide sidewalls in LC-DFB devices avoids any epitaxial overgrowth. This provides a considerable simplification in the fabrication process, reducing cost and time of manufacturing, and ultimately increasing yield. It offers also the potential for monolithic integration with other devices; paving the way towards low-cost and mass-production of photonics integrated circuits. In this work, we report on the realization of high-order grating InGaAsP/InP multiple-quantum-well (MQW) LC-DFB lasers at 1.55 μm by means of stepper lithography and inductively-coupled reactive-ion as well as wet chemical etching. Third-order rectangular-shaped grating has been lithographically defined on the ridge waveguide sidewalls with a relatively deep etching along the laser cavity. The preliminary experimental characterization shows interesting results for as-cleaved devices tested in room temperature under CW operation. A fabricated 1500 μm-long cavity LC-DFB laser shows stable single-mode operation with a side mode suppression ratio as high as 50 dB. The tested device can emit at power as high as 9 mW, and the measured threshold current is around 80 mA at room temperature. Moreover, the measured linewidth has been found to be as narrow as 178 kHz using the delayed self-heterodyne interferometric technique.
Faccinetto, Alessandro; Mazzucato, Simone; Pedron, Danilo; Bozio, Renato; Destri, Silvia; Porzio, William
2008-10-06
The nonlinear optical properties of a functionalized poly(thiophene azine), namely, poly(3,4-didodecylthiophene azine), PAZ, at the optical telecommunication wavelength of 1550 nm are investigated by means of the closed-aperture z-scan technique in both thin films and solutions. Values of chi((3))=(2.4+/-0.4)x10(-13) esu, n(2)=(4.0+/-0.7)x10(-15) cm(2) W(-1), and gamma=(4.5+/-0.7)x10(-34) esu are estimated for the third-order (Kerr) susceptibility, the intensity-dependent refractive index, and the molecular second hyperpolarizability of solution samples, respectively. A very small dependence on the polymer chain length is found. Markedly higher values of (4.4+/-1.1)x10(-11) esu, (6.6+/-1.0)x10(-13) cm(2) W(-1), and (5.0+/-0.8)x10(-33) esu are measured for the corresponding quantities in thick (up to 20 mum) polymer films cast on quartz plates. The enhancement of the NLO responses on going from solution to solid samples is attributed to a partially ordered structure and to the presence of interchain interactions leading to greater pi-electron delocalization in the cast polymer films. The results are compared with those previously obtained by using third-harmonic generation (THG), taking into account that those data were measured under conditions of three-photon resonance, whereas our z-scan measurements are fully off-resonance.
Xia, Yidong; Liu, Xiaodong; Luo, Hong; ...
2015-06-01
Here, a space and time third-order discontinuous Galerkin method based on a Hermite weighted essentially non-oscillatory reconstruction is presented for the unsteady compressible Euler and Navier–Stokes equations. At each time step, a lower-upper symmetric Gauss–Seidel preconditioned generalized minimal residual solver is used to solve the systems of linear equations arising from an explicit first stage, single diagonal coefficient, diagonally implicit Runge–Kutta time integration scheme. The performance of the developed method is assessed through a variety of unsteady flow problems. Numerical results indicate that this method is able to deliver the designed third-order accuracy of convergence in both space and time,more » while requiring remarkably less storage than the standard third-order discontinous Galerkin methods, and less computing time than the lower-order discontinous Galerkin methods to achieve the same level of temporal accuracy for computing unsteady flow problems.« less
Xia, Yidong; Liu, Xiaodong; Luo, Hong; Nourgaliev, Robert
2015-06-01
Here, a space and time third-order discontinuous Galerkin method based on a Hermite weighted essentially non-oscillatory reconstruction is presented for the unsteady compressible Euler and Navier–Stokes equations. At each time step, a lower-upper symmetric Gauss–Seidel preconditioned generalized minimal residual solver is used to solve the systems of linear equations arising from an explicit first stage, single diagonal coefficient, diagonally implicit Runge–Kutta time integration scheme. The performance of the developed method is assessed through a variety of unsteady flow problems. Numerical results indicate that this method is able to deliver the designed third-order accuracy of convergence in both space and time, while requiring remarkably less storage than the standard third-order discontinous Galerkin methods, and less computing time than the lower-order discontinous Galerkin methods to achieve the same level of temporal accuracy for computing unsteady flow problems.
NASA Astrophysics Data System (ADS)
Wenzel, Jan; Holzer, Andre; Wormit, Michael; Dreuw, Andreas
2015-06-01
The extended second order algebraic-diagrammatic construction (ADC(2)-x) scheme for the polarization operator in combination with core-valence separation (CVS) approximation is well known to be a powerful quantum chemical method for the calculation of core-excited states and the description of X-ray absorption spectra. For the first time, the implementation and results of the third order approach CVS-ADC(3) are reported. Therefore, the CVS approximation has been applied to the ADC(3) working equations and the resulting terms have been implemented efficiently in the adcman program. By treating the α and β spins separately from each other, the unrestricted variant CVS-UADC(3) for the treatment of open-shell systems has been implemented as well. The performance and accuracy of the CVS-ADC(3) method are demonstrated with respect to a set of small and middle-sized organic molecules. Therefore, the results obtained at the CVS-ADC(3) level are compared with CVS-ADC(2)-x values as well as experimental data by calculating complete basis set limits. The influence of basis sets is further investigated by employing a large set of different basis sets. Besides the accuracy of core-excitation energies and oscillator strengths, the importance of cartesian basis functions and the treatment of orbital relaxation effects are analyzed in this work as well as computational timings. It turns out that at the CVS-ADC(3) level, the results are not further improved compared to CVS-ADC(2)-x and experimental data, because the fortuitous error compensation inherent in the CVS-ADC(2)-x approach is broken. While CVS-ADC(3) overestimates the core excitation energies on average by 0.61% ± 0.31%, CVS-ADC(2)-x provides an averaged underestimation of -0.22% ± 0.12%. Eventually, the best agreement with experiments can be achieved using the CVS-ADC(2)-x method in combination with a diffuse cartesian basis set at least at the triple-ζ level.
Wenzel, Jan; Holzer, Andre; Wormit, Michael; Dreuw, Andreas
2015-06-07
The extended second order algebraic-diagrammatic construction (ADC(2)-x) scheme for the polarization operator in combination with core-valence separation (CVS) approximation is well known to be a powerful quantum chemical method for the calculation of core-excited states and the description of X-ray absorption spectra. For the first time, the implementation and results of the third order approach CVS-ADC(3) are reported. Therefore, the CVS approximation has been applied to the ADC(3) working equations and the resulting terms have been implemented efficiently in the adcman program. By treating the α and β spins separately from each other, the unrestricted variant CVS-UADC(3) for the treatment of open-shell systems has been implemented as well. The performance and accuracy of the CVS-ADC(3) method are demonstrated with respect to a set of small and middle-sized organic molecules. Therefore, the results obtained at the CVS-ADC(3) level are compared with CVS-ADC(2)-x values as well as experimental data by calculating complete basis set limits. The influence of basis sets is further investigated by employing a large set of different basis sets. Besides the accuracy of core-excitation energies and oscillator strengths, the importance of cartesian basis functions and the treatment of orbital relaxation effects are analyzed in this work as well as computational timings. It turns out that at the CVS-ADC(3) level, the results are not further improved compared to CVS-ADC(2)-x and experimental data, because the fortuitous error compensation inherent in the CVS-ADC(2)-x approach is broken. While CVS-ADC(3) overestimates the core excitation energies on average by 0.61% ± 0.31%, CVS-ADC(2)-x provides an averaged underestimation of -0.22% ± 0.12%. Eventually, the best agreement with experiments can be achieved using the CVS-ADC(2)-x method in combination with a diffuse cartesian basis set at least at the triple-ζ level.
Bozkaya, Uğur
2011-12-14
In this research, orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) and its spin-component and spin-opposite scaled variants (SCS-OMP3 and SOS-OMP3) are introduced. Using a Lagrangian-based approach, an efficient, quadratically convergent algorithm for variational optimization of the molecular orbitals (MOs) for third-order Møller-Plesset perturbation theory (MP3) is presented. Explicit equations for response density matrices, the MO gradient, and Hessian are reported in spin-orbital form. The OMP3, SCS-OMP3, and SOS-OMP3 approaches are compared with the second-order Møller-Plesset perturbation theory (MP2), MP3, coupled-cluster doubles (CCD), optimized-doubles (OD), and coupled-cluster singles and doubles (CCSD) methods. All these methods are applied to the O(4)(+), O(3), and seven diatomic molecules. Results demonstrate that the OMP3 and its variants provide significantly better vibrational frequencies than MP3, CCSD, and OD for the molecules where the symmetry-breaking problems are observed. For O(4)(+), the OMP3 prediction, 1343 cm(-1), for ω(6) (b(3u)) mode, where symmetry-breaking appears, is even better than presumably more reliable methods such as Brueckner doubles (BD), 1194 cm(-1), and OD, 1193 cm(-1), methods (the experimental value is 1320 cm(-1)). For O(3), the predictions of SCS-OMP3 (1143 cm(-1)) and SOS-OMP3 (1165 cm(-1)) are remarkably better than the more robust OD method (1282 cm(-1)); the experimental value is 1089 cm(-1). For the seven diatomics, again the SCS-OMP3 and SOS-OMP3 methods provide the lowest average errors, ∣Δω(e)∣ = 44 and ∣Δω(e)∣ = 35 cm(-1), respectively, while for OD, ∣Δω(e)∣ = 161 cm(-1)and CCSD ∣Δω(e)∣ = 106 cm(-1). Hence, the OMP3 and especially its spin-scaled variants perform much better than the MP3, CCSD, and more robust OD approaches for considered test cases. Therefore, considering both the computational cost and the reliability, SCS-OMP3 and SOS-OMP3 appear to be the
NASA Astrophysics Data System (ADS)
Bozkaya, Uǧur
2011-12-01
In this research, orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) and its spin-component and spin-opposite scaled variants (SCS-OMP3 and SOS-OMP3) are introduced. Using a Lagrangian-based approach, an efficient, quadratically convergent algorithm for variational optimization of the molecular orbitals (MOs) for third-order Møller-Plesset perturbation theory (MP3) is presented. Explicit equations for response density matrices, the MO gradient, and Hessian are reported in spin-orbital form. The OMP3, SCS-OMP3, and SOS-OMP3 approaches are compared with the second-order Møller-Plesset perturbation theory (MP2), MP3, coupled-cluster doubles (CCD), optimized-doubles (OD), and coupled-cluster singles and doubles (CCSD) methods. All these methods are applied to the O4 +, O3, and seven diatomic molecules. Results demonstrate that the OMP3 and its variants provide significantly better vibrational frequencies than MP3, CCSD, and OD for the molecules where the symmetry-breaking problems are observed. For O4 +, the OMP3 prediction, 1343 cm-1, for ω6 (b3u) mode, where symmetry-breaking appears, is even better than presumably more reliable methods such as Brueckner doubles (BD), 1194 cm-1, and OD, 1193 cm-1, methods (the experimental value is 1320 cm-1). For O3, the predictions of SCS-OMP3 (1143 cm-1) and SOS-OMP3 (1165 cm-1) are remarkably better than the more robust OD method (1282 cm-1); the experimental value is 1089 cm-1. For the seven diatomics, again the SCS-OMP3 and SOS-OMP3 methods provide the lowest average errors, |Δωe| = 44 and |Δωe| = 35 cm-1, respectively, while for OD, |Δωe| = 161 cm-1and CCSD |Δωe| = 106 cm-1. Hence, the OMP3 and especially its spin-scaled variants perform much better than the MP3, CCSD, and more robust OD approaches for considered test cases. Therefore, considering both the computational cost and the reliability, SCS-OMP3 and SOS-OMP3 appear to be the best methods for the symmetry-breaking cases, based on
ERIC Educational Resources Information Center
Rijmen, Frank; Jeon, Minjeong; von Davier, Matthias; Rabe-Hesketh, Sophia
2014-01-01
Second-order item response theory models have been used for assessments consisting of several domains, such as content areas. We extend the second-order model to a third-order model for assessments that include subdomains nested in domains. Using a graphical model framework, it is shown how the model does not suffer from the curse of…
Russell F. Thurow; James T. Peterson; John W. Guzevich
2006-01-01
Despite the widespread use of underwater observation to census stream-dwelling fishes, the accuracy of snorkeling methods has rarely been validated. We evaluated the efficiency of day and night snorkel counts for estimating the abundance of bull trout Salvelinus confluentus in 215 sites within first- to third-order streams. We used a dual-gear...
Montanez, I.P.; Droser, M.L. )
1991-03-01
The Middle to Late Cambrian Bonanza King Formation (CA, NV) is characterized by superimposed scales of cyclicity. Small-scale cycles (0.5 to 10m) occur as shallowing-upward peritidal and subtidal cycles that repeat at high frequencies (10{sup 4} to 10{sup 5}). Systematic changes in stacking patterns of meter-scale cycles define several large-scale (50-250 m) third-order depositional sequences in the Bonanza King Formation. Third-order depositional sequences can be traced within ranges and correlated regionally across the platform. Peritidal cycles in the Bonanza King Formation are both subtidal- and tidal flat-dominated. Tidal flat-dominated cycles consist of muddy bases grading upward into thrombolites or columnar stromatolites all capped by planar stromatolites. Subtidal cycles in the Bonanza King Formation consist of grainstone bases that commonly fine upward and contain stacked hardgrounds. These are overlain by digitate-algal bioherms with grainstone channel fills and/or bioturbated ribbon carbonates with grainstone lenses. Transgressive depositional facies of third-order depositional sequences consist primarily of stacks of subtidal-dominated pertidial cycles and subtidal cycles, whereas regressive depositional facies are dominated by stacks of tidal flat-dominated peritidal cycles and regoliths developed over laminite cycle caps. The use of high frequency cycles in the Bonanza King Formation to delineate regionally developed third-order depositional sequences thus provides a link between cycle stratigraphy and sequence stratigraphy.
NASA Astrophysics Data System (ADS)
Matsumi, Yusuke; Nakano, Hiroshi; Sato, Hirofumi
2017-08-01
We investigated a Pt electrode-water molecules system by constant potential molecular dynamics simulations using two different models for electronically polarizable metal electrodes. Static quantities were calculated such as the number density profiles, electrostatic potential profiles, and the potential of mean force profiles for the approach of a Na+ to an electrode. The two models were compared to find out they give results in good agreement with each other. The electrostatic potential acting on the Na+ was also evaluated and decomposed to get insight into the importance of the interactions between a redox species and polarizable metal electrodes.
Chang, Kan-Fa; Hwang, Sheau-Fang; Khadhair, Abdul-Hameed; Kawchuk, Lawrence; Howard, Ronald
2004-01-01
Queen Anne's lace and poker statice plants were found with a yellows-type disease with typical phytoplasma symptoms in an experimental farm near Brooks, Alberta in 1996. Phytoplasma bodies were detected by transmission electron microscopy in phloem cells of symptomatic plants, but not in healthy plants. The presence of a phytoplasma was confirmed by analysis with the polymerase chain reaction. Using a pair of universal primer sequences derived from phytoplasma 16S rRNA, an amplified product of the expected size (1.2 kb) was observed in samples from infected plants, but not in asymptomatic plants. Sequence analysis of the PCR products from the 16S/23S rDNA intergenic spacer region indicated that the two phytoplasma isolates in Queen Anne's lace and poker statice are genetically closely related to the western aster yellows phytoplasma.
Cassano, T; Tommasi, R; Babudri, F; Cardone, A; Farinola, G M; Naso, F
2002-12-15
The third-order nonlinear optical properties of a series of copoly(2, 3, 5, 6-tetrafluoro-1, 4-phenylenevinylene-2, 5-dioctyloxy-1, 4-phenylenevinylene) that contain variable ratios of two differently substituted monomers have been studied in chloroform solutions at l=1064 nm by the picosecond Z-scan technique. Nonlinear refractive index n(2) of the samples investigated has been found to be negative, and a strong dependence of its magnitude on the copolymer's composition has been observed. The highest third-order nonlinear optical susceptibility, |x((3))|=(6 +/- 2)x 10(-10) esu, was measured for a copolymer obtained by reaction of equimolar quantitites of the parent monomers.
NASA Astrophysics Data System (ADS)
Tang, Yiwen; Liu, Hui; Zhang, Hui; Li, Dandan; Su, Jian; Zhang, Shengyi; Zhou, Hongping; Li, Shengli; Wu, Jieying; Tian, Yupeng
2017-03-01
A series of water-soluble stilbazolium salts with A-π-A (A: Acceptor) model have been synthesized and fully characterized. The results obtained from absorption spectra and TD-DFT computational studies show that there is a relative strong intramolecular charge transfer (ICT) transition from pyridine unit to pyridine cation of the stilbazolium salts. Furthermore, it is found that the three stilbazolium salts (T1, T2, T3) show the strong two-photon absorption (2PA) response in the near-infrared (IR) region by Z-scan technique using femtosecond laser. And the stilbazolium salt T3 shows the largest two-photon absorption cross-section and third-order nonlinear optical (NLO) coefficient χ(3) at 730 nm, indicating the different terminal substituent group of the pyridinium plays a vital role in third-order NLO behavior.
Tang, Yiwen; Liu, Hui; Zhang, Hui; Li, Dandan; Su, Jian; Zhang, Shengyi; Zhou, Hongping; Li, Shengli; Wu, Jieying; Tian, Yupeng
2017-03-15
A series of water-soluble stilbazolium salts with A-π-A (A: Acceptor) model have been synthesized and fully characterized. The results obtained from absorption spectra and TD-DFT computational studies show that there is a relative strong intramolecular charge transfer (ICT) transition from pyridine unit to pyridine cation of the stilbazolium salts. Furthermore, it is found that the three stilbazolium salts (T1, T2, T3) show the strong two-photon absorption (2PA) response in the near-infrared (IR) region by Z-scan technique using femtosecond laser. And the stilbazolium salt T3 shows the largest two-photon absorption cross-section and third-order nonlinear optical (NLO) coefficient χ((3)) at 730nm, indicating the different terminal substituent group of the pyridinium plays a vital role in third-order NLO behavior. Copyright © 2016 Elsevier B.V. All rights reserved.
Syromyatnikov, A V
2010-06-02
The spectrum of short-wavelength magnons in a two-dimensional quantum Heisenberg antiferromagnet on a square lattice is calculated to the third order in a 1/S expansion. It is shown that a 1/S series for S = 1/2 converges quickly in the whole Brillouin zone except in the neighborhood of the point k = (π, 0), at which absolute values of the third-and the second-order 1/S-corrections are approximately equal to each other. It is shown that the third-order corrections make deeper the roton-like local minimum at k = (π, 0), improving the agreement with recent experiments and numerical results in the neighborhood of this point. It is suggested that the 1/S series converges slowly near k = (π, 0) also for S = 1 although the spectrum renormalization would be small in this case due to the very small values of high-order 1/S corrections.
Study of the third order nonlinear optical properties of Zn1-xMgxSe and Cd1-xMgxSe crystals
NASA Astrophysics Data System (ADS)
Derkowska, B.; Firszt, F.; Sahraoui, B.; Marasek, A.; Kujawa, M.
2008-03-01
Third order nonlinear optical susceptibilities χ<3> of ternary Zn1-xMgxSe and Cd1-xMgxSe crystals have been measured using standard degenerate four-wave mixing (DFWM) method at 532 nm. The nonlinear transmission technique has been applied to check if our crystals exhibit two-photon absorption. The studied Zn1-xMgxSe and Cd1-xMgxSe solid solutions were grown from the melt by the modified high-pressure Bridgman method. For both crystals the energy gap increases with increasing Mg content. In the case of Zn1-xMgxSe, it was found that the value of third order nonlinear optical susceptibility χ<3> decreases with increasing Mg content. An explanation of this behaviour results from the dependence of optical nonlinearities on the energy band gap Eg of the studied crystals. In the case of Cd1txMgxSe with low content of Mg, no response was observed for the studied wavelength since the energy gap in such crystals is smaller than the photon energy of the used laser radiation. It was also found that the value of third order nonlinear optical susceptibility χ<3> for Cd0.70Mg0.30Se is higher than for Zn0.67Mg0.33Se. This behaviour can be understood if one take into consideration that the free carrier concentration in Cd1-xMgxSe samples is about four orders of magnitude higher than that in Zn1txMgxSe ones with comparable Mg content respectively. It is commonly known that when the electric conductivity increases, the values of nonlinear optical properties increase. From the performed measurements one can conclude that the incorporation of Mg as constituent into ZnSe and CdSe crystals leads to a change of the third order nonlinear optical susceptibilities.
Generation of 13-fs pulses from a mode-locked Ti:Al2O3 laser with reduced third-order dispersion
NASA Astrophysics Data System (ADS)
Proctor, Bob; Wise, Frank
1993-02-01
The third-order dispersion of a mode-locked Ti:Al2O3 laser has been reduced by replacing a pair of flint glass prisms with a sequence of four quartz prisms. This allows transform-limited 13-fs pulses to be generated with a gain crystal 20 mm long. To date, these are the shortest pulses generated directly from a laser.
NASA Astrophysics Data System (ADS)
Pitonak, Martin; Sprlak, Michal; Novak, Pavel; Tenzer, Robert
2016-04-01
Recently realized gravity-dedicated satellite missions allow for measuring values of scalar, vectorial (Gravity Recovery And Climate Experiment - GRACE) and second-order tensorial (Gravity field and steady-state Ocean Circulation Explorer - GOCE) parameters of the Earth's gravitational potential. Theoretical aspects related to using moving sensors for measuring elements of the third-order gravitational tensor are currently under investigation, e.g., the gravity field-dedicated satellite mission OPTIMA (OPTical Interferometry for global Mass change detection from space) should measure third-order derivatives of the Earth's gravitational potential. This contribution investigates regional recovery of the disturbing gravitational potential on the Earth's surface from satellite and aerial observations of the first-, second- and third-order radial derivatives of the disturbing gravitational potential. Synthetic measurements along a satellite orbit at the altitude of 250 km and along an aircraft track at the altitude of 10 km are synthetized from the global gravitational model EGM2008 and polluted by the Gaussian noise. The process of downward continuation is stabilized by the Tikhonov regularization. Estimated values of the disturbing gravitational potential are compared with the same quantity synthesized directly from EGM2008.
Chen, Yong; Yan, Zhenya
2016-03-22
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields.
NASA Astrophysics Data System (ADS)
Novak, P.; Pitonak, M.; Sprlak, M.
2015-12-01
Recently realized gravity-dedicated satellite missions allow for measuring values of scalar, vectorial (Gravity Recovery And Climate Experiment - GRACE) and second-order tensorial (Gravity field and steady-state Ocean Circulation Explorer - GOCE) parameters of the Earth's gravitational potential. Theoretical aspects related to using moving sensors for measuring elements of a third-order gravitational tensor are currently under investigation, e.g. the gravity-dedicated satellite mission OPTIMA (OPTical Interferometry for global Mass change detection from space) should measure third-order derivatives of the Earth's gravitational potential. This contribution investigates regional recovery of the disturbing gravitational potential on the Earth's surface from satellite observations of first-, second- and third-order radial derivatives of the disturbing gravitational potential. Synthetic measurements along a satellite orbit at the altitude of 250 km are synthetized from the global gravitational model EGM2008 and polluted by the Gaussian noise. The process of downward continuation is stabilized by the Tikhonov regularization. Estimated values of the disturbing gravitational potential are compared with the same quantity synthesized directly from EGM2008. Finally, this contribution also discusses merging a regional solution into a global field as a patchwork.
Chen, Yong; Yan, Zhenya
2016-01-01
Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields. PMID:27002543
Alcaráz, Mirta R; Bortolato, Santiago A; Goicoechea, Héctor C; Olivieri, Alejandro C
2015-03-01
Matrix augmentation is regularly employed in extended multivariate curve resolution-alternating least-squares (MCR-ALS), as applied to analytical calibration based on second- and third-order data. However, this highly useful concept has almost no correspondence in parallel factor analysis (PARAFAC) of third-order data. In the present work, we propose a strategy to process third-order chromatographic data with matrix fluorescence detection, based on an Augmented PARAFAC model. The latter involves decomposition of a three-way data array augmented along the elution time mode with data for the calibration samples and for each of the test samples. A set of excitation-emission fluorescence matrices, measured at different chromatographic elution times for drinking water samples, containing three fluoroquinolones and uncalibrated interferences, were evaluated using this approach. Augmented PARAFAC exploits the second-order advantage, even in the presence of significant changes in chromatographic profiles from run to run. The obtained relative errors of prediction were ca. 10 % for ofloxacin, ciprofloxacin, and danofloxacin, with a significant enhancement in analytical figures of merit in comparison with previous reports. The results are compared with those furnished by MCR-ALS.
NASA Astrophysics Data System (ADS)
Futera, Zdenek; English, Niall J.
2017-07-01
The response of water to externally applied electric fields is of central relevance in the modern world, where many extraneous electric fields are ubiquitous. Historically, the application of external fields in non-equilibrium molecular dynamics has been restricted, by and large, to relatively inexpensive, more or less sophisticated, empirical models. Here, we report long-time non-equilibrium ab initio molecular dynamics in both static and oscillating (time-dependent) external electric fields, therefore opening up a new vista in rigorous studies of electric-field effects on dynamical systems with the full arsenal of electronic-structure methods. In so doing, we apply this to liquid water with state-of-the-art non-local treatment of dispersion, and we compute a range of field effects on structural and dynamical properties, such as diffusivities and hydrogen-bond kinetics.
NASA Astrophysics Data System (ADS)
Felmy, Andrew R.; Rustad, James R.
1998-01-01
Molecular statics calculations of proton binding at the hydroxylated faces of goethite are used to guide the development of a thermodynamic model which describes the surface charging properties of goethite in electrolyte solutions. The molecular statics calculations combined with a linear free energy relation between the energies of the hydroxylated surface and the aqueous solvated surface predict that the acidity constants for most singly (aqua or hydroxo), doubly (μ-hydroxo), and triply (μ 3-hydroxo or μ 3-oxo) coordinated surface sites all have similar values. This model which binds protons to the goethite 110 and 021 faces satisfactorily describes the surface charging behavior of goethite, if pair formation between bulk electrolyte species, i.e., Na +, Cl -, and NO 3-, is included in the model. Inclusion of minor species of quite different charging behavior (designed to describe the possible presence of defect species) did not improve our predictions of surface charge since the protonation of the major surface sites changed when these minor species were introduced into the calculations thereby negating the effect of small amounts of defect species on the overall charging behavior. The final thermodynamic model is shown to be consistent with the surface charging properties of goethite over a range of pH values, NaNO 3, and NaCl concentrations.
Li, Haipeng; Xu, Hu; Shen, Xiaopeng; Han, Kui; Bi, Zetong; Xu, Runfeng
2016-01-01
We investigated the electronic properties and second hyperpolarizabilities of hydrogenated silicon nanoclusters (H-SiNCs) by using the density functional theory method. The effects of cluster size, external electric field and incident frequency on the second hyperpolarizability were also examined, respectively. We found that small H-SiNCs exhibit large second hyperpolarizability. With the increase of the number of silicon atoms in H-SiNCs, the frontier molecular orbital energy gap decreases, attributed to the enhancement of the second hyperpolarizability. Interestingly, we also found the electric-field-induced gigantic enhancement of the second hyperpolarizability for H-SiNCs due to the change of electron density distributions. In addition, our results demonstrate a significant dependence on the frequency of incident light. PMID:27305957
NASA Astrophysics Data System (ADS)
Li, Haipeng; Xu, Hu; Shen, Xiaopeng; Han, Kui; Bi, Zetong; Xu, Runfeng
2016-06-01
We investigated the electronic properties and second hyperpolarizabilities of hydrogenated silicon nanoclusters (H-SiNCs) by using the density functional theory method. The effects of cluster size, external electric field and incident frequency on the second hyperpolarizability were also examined, respectively. We found that small H-SiNCs exhibit large second hyperpolarizability. With the increase of the number of silicon atoms in H-SiNCs, the frontier molecular orbital energy gap decreases, attributed to the enhancement of the second hyperpolarizability. Interestingly, we also found the electric-field-induced gigantic enhancement of the second hyperpolarizability for H-SiNCs due to the change of electron density distributions. In addition, our results demonstrate a significant dependence on the frequency of incident light.
Đorđević, L; Marangoni, T; De Leo, F; Papagiannouli, I; Aloukos, P; Couris, S; Pavoni, E; Monti, F; Armaroli, N; Prato, M; Bonifazi, D
2016-04-28
By means of different spectroscopic techniques, we investigate a novel series of porphyrin derivatives (H2TPP), connected to dibenzo-24-crown-8 (DB24C8) moieties, which undergo self-assembly with different methano[60]fullerene units bearing dibenzylammonium (DBA) cations. The formation of both [2] and [3]pseudorotaxanes was proved by means of NMR, UV-Vis-NIR absorption and emission spectroscopies. With the support of molecular modelling studies, spectroscopic investigations showed the presence of a secondary interaction between the porphyrin and the C60 chromophores leading to the formation of different types of "face-to-face" assemblies. Remarkably, investigations of the non-linear optical response of these supramolecular systems showed that individual porphyrin and fullerene derivatives exhibit significantly lower second hyperpolarizability values when compared to their pseudorotaxanes functionalised counterparts. This proves that this class of supramolecular materials possesses relevant NLO response, which strongly depends on the structural arrangement of the chromophores in solution.
Teran, Natasha B; He, Guang S; Baev, Alexander; Shi, Yanrong; Swihart, Mark T; Prasad, Paras N; Marks, Tobin J; Reynolds, John R
2016-06-08
Exploiting synergistic cooperation between multiple sources of optical nonlinearity, we report the design, synthesis, and nonlinear optical properties of a series of electron-rich thiophene-containing donor-acceptor chromophores with condensed π-systems and sterically regulated inter-aryl twist angles. These structures couple two key mechanisms underlying optical nonlinearity, namely, (i) intramolecular charge transfer, greatly enhanced by increased electron density and reduced aromaticity at chromophore thiophene rings and (ii) a twisted chromophore geometry, producing a manifold of close-lying excited states and dipole moment changes between ground and excited states that are nearly twice that of untwisted systems. Spectroscopic, electrochemical, and nonlinear Z-scan measurements, combined with quantum chemical calculations, illuminate relationships between molecular structure and mechanisms of enhancement of the nonlinear refractive index. Experiment and calculations together reveal ground-state structures that are strongly responsive to the solvent polarity, leading to substantial negative solvatochromism (Δλ ≈ 10(2) nm) and prevailing zwitterionic/aromatic structures in the solid state and in polar solvents. Ground-to-excited-state energy gaps below 2.0 eV are obtained in condensed π-systems, with lower energy gaps for twisted versus untwisted systems. The real part of the second hyperpolarizability in the twisted structures is much greater than the imaginary part, with the highest twist angle chromophore giving |Re(γ)/Im(γ)| ≈ 100, making such chromophores very promising for all-optical-switching applications.
Fukui, Hitoshi; Inoue, Yudai; Yamada, Taishi; Ito, Soichi; Shigeta, Yasuteru; Kishi, Ryohei; Champagne, Benoît; Nakano, Masayoshi
2012-06-07
Metal-metal multiply bonded complexes in their singlet state have been predicted to form a novel class of "σ-dominant" third-order nonlinear optical compounds based on the results of dichromium(II) and dimolybdenum(II) systems (H. Fukui et al. J. Phys. Chem. Lett.2011, 2, 2063) whose second hyperpolarizabilities (γ) are enhanced by the contribution of the dσ electrons with an intermediate diradical character. In this study, using the spin-unrestricted coupled-cluster method with singles and doubles as well as with perturbative triples, we investigate the dependences of γ on the group and on the period of the transition metals as well as on their atomic charges in several open-shell singlet dimetallic systems. A significant enhancement of γ is observed in those dimetallic systems composed of (i) transition metals with a small group number, (ii) transition metals with a large periodic number, and (iii) transition metals with a small positive charge. From the decomposition of the γ values into the contributions of dσ, dπ, and dδ electrons, the γ enhancements are shown to originate from the dσ contribution, because it corresponds to the intermediate diradical character region. Furthermore, the amplitude of dσ contribution turns out to be related to the size of the d(z(2)) atomic orbital of the transition metal, which accounts for the dependence of γ on the group, on the period, and on the charge of the metal atoms. These dependences provide a guideline for an effective molecular design of highly efficient third-order nonlinear optical (NLO) systems based on the metal-metal bonded systems.
Suzuki, Katsuaki; Kubo, Shosei; Aussenac, Fabien; Engelke, Frank; Fukushima, Tatsuya; Kaji, Hironori
2017-10-09
Molecular orientation in amorphous organic semiconducting thin film devices is an important issue affecting device performances. However, to date it has not been possible to analyze the "distribution" of the orientations. Although solid-state NMR (ssNMR) can provide information on the distribution of molecular orientations, the technique is limited because of the small amounts of sample in the devices and the low sensitivity of ssNMR. Here, we report the first application of dynamic nuclear polarization enhanced ssNMR (DNP-ssNMR) to orientational analysis of amorphous phenyldi(pyren-1-yl)phosphine oxide (POPy2). The 31P DNP-ssNMR spectra exhibited a sufficient signal-to-noise ratio to quantify the distribution of molecular orientations in amorphous films: the P=O axis of the vacuum-deposited and drop-cast POPy2 shows anisotropic and isotropic distribution, respectively. The different molecular orientations reflect the molecular origin of the different charge transport behaviors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Kominami, Taro; Ueno, Shinji; Okado, Satoshi; Nakanishi, Ayami; Kondo, Mineo; Terasaki, Hiroko
2017-03-01
To determine the contribution of second- and third-order retinal neurons to the photopic electroretinograms (ERGs) after the degeneration of the rods in rhodopsin P347L transgenic rabbits (Tg). Four wild-type (WT) rabbits and four Tg rabbits were studied at 18 months of age. The photopic ERGs elicited at stimulus onset and offset were analyzed. To block different retinal pathways, 2-amino-4-phosphonobutyric acid (APB), 6-cyano-7-nitroquinoxaline-2, 3 (1H,4H)-dione (CNQX), tetrodotoxin (TTX), and N-methyl-DL-aspartic acid (NMDA) were injected intravitreally. Digital subtraction of the postdrug ERGs from the predrug ERGs was used to determine the contributions of the ON-components blocked by APB, the OFF-components blocked by CNQX, and the third-order neurons blocked by TTX+NMDA. Contribution of the cone photoreceptors to the photopic ERGs in Tg rabbits was approximately 10% of that in WT rabbits. The amplitudes of the positive waves of the ON-components at stimulus onset in Tg rabbits were approximately one-half as large as those in WT. On the other hand, the amplitudes of the positive waves of the OFF-components at stimulus offset in Tg rabbits were approximately 1.4 to 2.3 times larger than those in WT. Transgenic rabbits had a positive wave at stimulus offset, which was reduced after the TTX+NMDA injection. A reduced ON-component and an augmented OFF-component with abnormal responses of the third-order neurons contributed to the cone ERGs after the loss of rod function in Tg rabbits. Our results suggest a complex synaptic remodeling of the residual retinal cells in the advanced stage in Tg rabbits.
Han, Xiuyou; Chen, Xiang; Yao, Jianping
2016-06-27
A microwave photonic link (MPL) with simultaneous suppression of the even-order and third-order distortions using a polarization modulator (PolM), an optical bandpass filter (OBPF), and a balanced photodetector (BPD) is proposed and experimentally demonstrated. The even-order distortions are suppressed by utilizing orthogonal polarization modulation based on the PolM and balanced differential detection based on the BPD. The third-order distortions (IMD3) are suppressed by optimizing the spectral response of the OBPF with an optimal power ratio between the optical carrier and the sidebands of the phase-modulated signals from the PolM. Since the suppression of the IMD3 is achieved when the MPL is optimized for even-order distortion suppression, the proposed MPL can operate with simultaneous suppression of the even-order and third-order distortions. The proposed MPL is analyzed theoretically and is verified by an experiment. For a two-tone RF signal of f_{1} = 10 GHz and f_{2} = 19.95 GHz, the spurious-free dynamic range (SFDR2) is enhanced by 23.4 dB for the second harmonic (2f_{1}), and 29.1 and 27.6 dB for the second intermodulation (f_{2}-f_{1} and f_{1} + f_{2}), as compared with a conventional MPL. For a two-tone RF signal of f_{1} = 9.95 GHz and f_{2} = 10 GHz, the SFDR3 is increased by 13.1 dB as compared with a conventional MPL.
NASA Astrophysics Data System (ADS)
Sudheesh, P.; Siji Narendran, N. K.; Chandrasekharan, K.
2013-12-01
Here we report a study on the third-order nonlinear optical properties of a new class of phenylhydrazones and the influence of silver and gold metal nanoparticles on their nonlinear response. Metal nanoparticles were prepared by laser ablation method. Single beam Z-scan technique with a 7 ns, 10 Hz Nd: YAG laser pulses at 532 nm were employed for the measurements. The compounds exhibit well optical limiting properties. Hence, these compounds are a promising class of materials for the optical device applications.
Curtiss, L. A.; Redfern, P. C.; Raghavachari, K.; Pople, J. A.; Chemistry; Lucent Tech.; Northwestern Univ.
1999-11-12
A variation of Gaussian-3 (G3) theory is presented in which third-order perturbation theory is used in place of fourth-order perturbation theory to decrease the computational requirements. This method, referred to as G3(MP3) theory, is assessed on 299 energies from the G2/97 test set. The average absolute deviation from experiment of G3(MP3) theory for the 299 energies is 1.22 kcal/mol. The importance of core-related correlation in various G3 methods is also discussed.
NASA Astrophysics Data System (ADS)
Wen, J.; Gao, Ch. Y.; Yu, H. T.; Zhao, M.; Shang, J. J.; Li, X. L.
2017-03-01
A new method for measuring third-order nonlinear optical properties of photo refractive materials based on modified Z-scan technique in which employing focus-tunable lens was proposed. By this method, the nonlinear refractive index and the nonlinear absorption coefficient of an undoped {{LiNb}}{{{O}}_{{3}}} crystal were investigated γ = - 1.48 × {10^{ - 12}}{{{m}}^{{2}}}{{/W}} and β = 0.33{{mm/W}}, respectively. The investigation suggests that the calculated results keep agreement with the traditional Z-scan technique in the order of magnitude.
NASA Astrophysics Data System (ADS)
Liu, Mi; Ma, Ming; Cui, Yiping; Zhang, Yu; Wang, Gang; Sun, Yongkang
2005-01-01
The third-order optical nonlinearity of Fe2O3 nanoparticles capped with glutamic acid molecules and bare particles in hydrosol have been investigated by Z-scan technique. The signs and magnitudes of nonlinear refractive coefficients (γ) of these two kinds Fe2O3 nanoparticles were obtained. The results suggested that γ was intensively subject to the surface-capping molecules. This phenomenon may be in particular considered with local field enhancement effect related to the refractive index of the media around nanoparticles, and the local field enhancement factor was evaluated by the solution of Laplace's equation.
Li, Jian; Zhang, Yi-Chen; Yu, Song; Jiang, Tianwei; Xie, Qian; Gu, Wanyi
2013-11-01
A method to realize a highly linear microwave photonics link is proposed based on the dual-drive dual-parallel Mach-Zehnder modulator (MZM). The scheme theoretically eliminates third-order intermodulation distortion (IMD3) completely by taking all the sidebands in the optical spectrum that cause IMD3 into consideration. Without digital linearization and other optical processors, the method utilizes simple electrical signal phase control. Microwave signals are symmetrically single sideband modulated in the two MZMs. IMD3 suppression of approximately 30 dB is experimentally demonstrated, and the spurious-free dynamic range is improved by 12 dB·Hz2/3.
NASA Astrophysics Data System (ADS)
Motiei, H.; Jafari, A.; Naderali, R.
2017-02-01
In this paper, two chemically synthesized organic azo dyes, 2-(2,5-Dichloro-phenyazo)-5,5-dimethyl-cyclohexane-1,3-dione (azo dye (i)) and 5,5-Dimethyl-2-tolylazo-cyclohexane-1,3-dione (azo dye (ii)), have been studied from optical Kerr nonlinearity point of view. These materials were characterized by Ultraviolet-visible spectroscopy. Experiments were performed using a continous wave diode-pumped laser at 532 nm wavelength in three intensities of the laser beam. Nonlinear absorption (β), refractive index (n2) and third-order susceptibility (χ (3)) of dyes, were calculated. Nonlinear absorption coefficient of dyes have been calculated from two methods; 1) using theoretical fits and experimental data in the Z-scan technique, 2) using the strength of nonlinearity curves. The values of β obtained from both of the methods were approximately the same. The results demonstrated that azo dye (ii) displays better nonlinearity and has a lower two-photon absorption threshold than azo dye (i). Calculated parameter related to strength of nonlinearity for azo dye (ii) was higher than azo dye (i), It may be due to presence of methyl in azo dye (ii) instead of chlorine in azo dye (i). Furthermore, The measured values of third order susceptibility of azo dyes were from the order of 10-9 esu . These azo dyes can be suitable candidate for optical switching devices.
NASA Astrophysics Data System (ADS)
Carrillo-Delgado, C.; García-Gil, C. I.; Trejo-Valdez, M.; Torres-Torres, C.; García-Merino, J. A.; Martínez-Gutiérrez, H.; Khomenko, A. V.; Torres-Martínez, R.
2016-01-01
Measurements of the third-order nonlinear optical properties exhibited by a ZnO thin solid film deposited on a SnO2 substrate are presented. The samples were prepared by a spray pyrolysis processing route. Scanning electron microscopy analysis and UV-Vis spectroscopy studies were carried out. The picosecond response at 1064 nm was explored by the z-scan technique. A large optical Kerr effect with two-photon absorption was obtained. The inhibition of the nonlinear optical absorption together with a noticeable enhancement in the optical Kerr effect in the sample was achieved by the incorporation of Au nanoparticles into the ZnO film. Additionally, a two-wave mixing configuration at 532 nm was performed and an optical Kerr effect was identified as the main cause of the nanosecond third-order optical nonlinearity. The relaxation time of the photothermal response of the sample was estimated to be about 1 s when the sample was excited by nanosecond single-shots. The rotation of the sample during the nanosecond two-wave mixing experiments was analyzed. It was stated that a non-monotonic relation between rotating frequency and pulse repetition rate governs the thermal contribution to the nonlinear refractive index exhibited by a rotating film. Potential applications for switching photothermal interactions in rotating samples can be contemplated. A rotary logic system dependent on Kerr transmittance in a two-wave mixing experiment was proposed.
Yoshimatsu, Katsunori
2012-06-01
The four-fifths law for third-order longitudinal moments is examined, using direct numerical simulation (DNS) data on three-dimensional (3D) forced incompressible magnetohydrodynamic (MHD) turbulence without a uniformly imposed magnetic field in a periodic box. The magnetic Prandtl number is set to one, and the number of grid points is 512(3). A generalized Kármán-Howarth-Kolmogorov equation for second-order velocity moments in isotropic MHD turbulence is extended to anisotropic MHD turbulence by means of a spherical average over the direction of r. Here, r is a separation vector. The viscous, forcing, anisotropic and nonstationary terms in the generalized equation are quantified. It is found that the influence of the anisotropic terms on the four-fifths law is negligible at small scales, compared to that of the viscous term. However, the influence of the directional anisotropy, which is measured by the departure of the third-order moments in a particular direction of r from the spherically averaged ones, on the four-fifths law is suggested to be substantial, at least in the case studied here.
NASA Astrophysics Data System (ADS)
Mageshwari, P. S. Latha; Priya, R.; Krishnan, S.; Joseph, V.; Das, S. Jerome
2016-11-01
A third order nonlinear optical (NLO)single crystals of sodium succinate hexahydrate (SSH) (β phase) has been grown by a slow evaporation growth technique using aqueous solution at ambient temperature. The lattice parameters and morphology of SSH were determined by single crystal X-ray diffraction analysis. SSH crystallizes in centrosymmetric monoclinic system with space group P 21 / c and the crystalline purity was analyzed by powder X-ray diffraction analysis. The UV-vis-NIR spectrum reveals that the crystal is transparent in the entire visible region. The recorded FT-IR spectrum verified the presence of various functional groups in the material. NMR analysis of the grown crystal confirms the structural elucidation and detects the major and minor functional groups present in the title compound. ICP-OES analysis proved the presence of sodium in SSH. TG-DTA/DSCanalysis was used to investigate the thermal stability of the material. The dielectric permittivity and dielectric loss of SSH were carried out as a function of frequency for different temperatures and the results were discussed. The mechanical stability was evaluated from Vicker's microhardness test. The third order nonlinear optical properties of SSH has been investigated employing Z-scan technique with He-Ne laser operating at 632.8 nm wavelength.
NASA Astrophysics Data System (ADS)
Patro, L. N.; Burghaus, O.; Roling, B.
2017-04-01
We have measured the third-order permittivity spectra ɛ33 of a monocationic and of a dicationic liquid close to the glass transition temperature by applying ac electric fields with large amplitudes up to 180 kV/cm. A peak ("hump") in the modulus of ɛ33 is observed for a mono-cationic liquid after subtraction of the dc contribution from the imaginary part of ɛ33. We show that the origin of this experimental "hump" is a peak in the imaginary part of ɛ33, with the peak height strongly increasing with decreasing temperature. Overall, the spectral shape of the third-order permittivity of both ionic liquids is similar to the predictions of a symmetric double well potential model, although this model does not predict a "hump" in the modulus. In contrast, an asymmetric double well potential model predicts a "hump," but the spectral shape of both the real and imaginary part of ɛ33 deviates significantly from the experimental spectra. These results show that not only the modulus of ɛ33 but also its phase is an important quantity when comparing experimental results with theoretical predictions.
NASA Astrophysics Data System (ADS)
Niestegge, Gerd
2014-04-01
Quantum probabilities differ from classical ones in many ways, e.g. by violating the well-known Bell and Clauser-Horne-Shimony-Holt inequalities or another simple inequality due to R Wright. The latter has recently regained attention because of its equivalence to a novel noncontextual inequality by Klyachko et al. On the other hand, quantum probabilities still obey many limitations which need not hold in more general probabilistic theories (super quantum probabilities). Wright, Popescu and Rohrlich identified states which are included in such theories, but impossible in quantum mechanics, and they showed this using the Hilbert space formalism. Recently, Fritz et al and Cabello detected that the impossibility of these states can be derived from very general principles (local orthogonality and global exclusive disjunction, respectively) without using Hilbert space techniques. In the paper, an alternative derivation from rather different physical principles will be presented. These are a reasonable calculus of conditional probability (i.e. a model for the quantum measurement process) and the absence of third-order interference. The concept of third-order interference was introduced by Sorkin, who also recognized its impossibility in quantum mechanics.
Goldhammer, R.K.; Lehmann, P.J.; Dunn, P.A. )
1993-05-01
The passive-margin succession of the Diablo Platform is represented by the second-order Sauk C supersequence set, consisting of a basal transgressive clastic unit (The Bliss Sandstone) above the breakup unconformity, marking the second-order basal lowstand transgressive phase, overlain by 750 m of drift-related, shallow-marine platform carbonate (the El Paso Group) recording the second-order highstand. Due to late Paleozoic structuring of the Gondwanan passive margin, present exposures in Texas are in an updip shelf position and lack internal stratal geometries across depositional strike, so sequences and systems tracts are identified solely by the vertical stacking patterns of depositional subfacies and higher-frequency, fifth-order cycles. By analysis of outcrop data the authors develop a sequence-stratigraphic model for lower Paleozoic passive-margin, shallow-water, platform carbonates that de-emphasizes the physical expression of sequence boundaries and systems-tract boundaries and focuses on the vertical and lateral, meter-scale cyclic and subfacies architecture of carbonate shelf deposits in the framework of third-order depositional sequences. They rely on analyses of stratal stacking patterns to bridge the gap from cycle-scale stratigraphy to seismic-scale sequence stratigraphy. In many settings, like the Permian of west Texas, sequence boundaries are often obvious, but in others, especially shallow-dipping ramps or flat-topped platforms on passive margins, third-order sequence boundaries are less obvious, particularly in deformed terranes lacking two-dimensional dip continuity.
NASA Astrophysics Data System (ADS)
Sun, S. X.-L.; Kaduwela, A. P.; Gray, A. X.; Fadley, C. S.
2014-05-01
The availability of short-pulse free-electron lasers has led to the idea of using photoelectron holography as a method of directly imaging molecular dissociations or reactions in real time, as, e.g., in a recent theoretical study by Krasniqi et al., [F. Krasniqi, B. Najjari, L. Strüder, D. Rolles, A. Voitkiv, and J. Ullrich, Phys. Rev. A 81, 033411 (2010), 10.1103/PhysRevA.81.033411]. In this paper, we extend this earlier work and in particular look at two critical questions concerning the optimum type of data required for such holographic imaging: the choice of photoelectron kinetic energy (e.g., ˜300 eV versus ˜1700 eV as in the prior study), and the use of a single energy or multiple energies. After verifying that our calculations fully duplicate those in this prior paper, we show that using lower energies is preferable to using higher energies for image quality, a conclusion consistent with prior photoelectron holography studies at surfaces, and that multiple lower energies in which the hologram effectively spans a volume in kspace yields the best quality images that should be useful for such "molecular movies." Although the amount of data required for such multi-energy holography is roughly an order of magnitude higher than that for single energy, the reduction of artifacts and the improved quality of the images suggest this as the optimum ultimate future strategy for such dynamic imaging.
Ganesh, P.; Jiang, D.; Kent, P.R.C.
2011-03-31
Lithium-ion batteries have the potential to revolutionize the transportation industry, as they did for wireless communication. A judicious choice of the liquid electrolytes used in these systems is required to achieve a good balance among high-energy storage, long cycle life and stability, and fast charging. Ethylene-carbonate (EC) and propylene-carbonate (PC) are popular electrolytes. However, to date, almost all molecular-dynamics simulations of these fluids rely on classical force fields, while a complete description of the functionality of Li-ion batteries will eventually require quantum mechanics. We perform accurate ab initio molecular-dynamics simulations of ethylene- and propylene-carbonate with LiPF6 at experimental concentrations to build solvation models which explain available neutron scattering and nuclear magnetic resonance (NMR) results and to compute Li-ion solvation energies and diffusion constants. Our results suggest some similarities between the two liquids as well as some important differences. Simulations also provide useful insights into formation of solid-electrolyte interphases in the presence of electrodes in conventional Li-ion batteries.
Ganesh, Panchapakesan; Jiang, Deen; Kent, Paul R
2011-01-01
Lithium-ion batteries have the potential to revolutionize the transportation industry, as they did for wireless communication. A judicious choice of the liquid electrolytes used in these systems is required to achieve a good balance among high-energy storage, long cycle life and stability, and fast charging. Ethylene-carbonate (EC) and propylene-carbonate (PC) are popular electrolytes. However, to date, almost all molecular-dynamics simulations of these fluids rely on classical force fields, while a complete description of the functionality of Li-ion batteries will eventually require quantum mechanics. We perform accurate ab initio molecular-dynamics simulations of ethylene- and propylene-carbonate with LiPF6 at experimental concentrations to build solvation models which explain available neutron scattering and nuclear magnetic resonance (NMR) results and to compute Li-ion solvation energies and diffusion constants. Our results suggest some similarities between the two liquids as well as some important differences. Simulations also provide useful insights into formation of solid-electrolyte interphases in the presence of electrodes in conventional Li-ion batteries.
Ganesh, P; Jiang, De-en; Kent, P R C
2011-03-31
Lithium-ion batteries have the potential to revolutionize the transportation industry, as they did for wireless communication. A judicious choice of the liquid electrolytes used in these systems is required to achieve a good balance among high-energy storage, long cycle life and stability, and fast charging. Ethylene-carbonate (EC) and propylene-carbonate (PC) are popular electrolytes. However, to date, almost all molecular-dynamics simulations of these fluids rely on classical force fields, while a complete description of the functionality of Li-ion batteries will eventually require quantum mechanics. We perform accurate ab initio molecular-dynamics simulations of ethylene- and propylene-carbonate with LiPF(6) at experimental concentrations to build solvation models which explain available neutron scattering and nuclear magnetic resonance (NMR) results and to compute Li-ion solvation energies and diffusion constants. Our results suggest some similarities between the two liquids as well as some important differences. Simulations also provide useful insights into formation of solid-electrolyte interphases in the presence of electrodes in conventional Li-ion batteries.
NASA Technical Reports Server (NTRS)
Cheng, Anning; Xu, Kuan-Man
2006-01-01
The abilities of cloud-resolving models (CRMs) with the double-Gaussian based and the single-Gaussian based third-order closures (TOCs) to simulate the shallow cumuli and their transition to deep convective clouds are compared in this study. The single-Gaussian based TOC is fully prognostic (FP), while the double-Gaussian based TOC is partially prognostic (PP). The latter only predicts three important third-order moments while the former predicts all the thirdorder moments. A shallow cumulus case is simulated by single-column versions of the FP and PP TOC models. The PP TOC improves the simulation of shallow cumulus greatly over the FP TOC by producing more realistic cloud structures. Large differences between the FP and PP TOC simulations appear in the cloud layer of the second- and third-order moments, which are related mainly to the underestimate of the cloud height in the FP TOC simulation. Sensitivity experiments and analysis of probability density functions (PDFs) used in the TOCs show that both the turbulence-scale condensation and higher-order moments are important to realistic simulations of the boundary-layer shallow cumuli. A shallow to deep convective cloud transition case is also simulated by the 2-D versions of the FP and PP TOC models. Both CRMs can capture the transition from the shallow cumuli to deep convective clouds. The PP simulations produce more and deeper shallow cumuli than the FP simulations, but the FP simulations produce larger and wider convective clouds than the PP simulations. The temporal evolutions of cloud and precipitation are closely related to the turbulent transport, the cold pool and the cloud-scale circulation. The large amount of turbulent mixing associated with the shallow cumuli slows down the increase of the convective available potential energy and inhibits the early transition to deep convective clouds in the PP simulation. When the deep convective clouds fully develop and the precipitation is produced, the cold pools
NASA Astrophysics Data System (ADS)
Reale, Riccardo; English, Niall J.; Garate, José-Antonio; Marracino, Paolo; Liberti, Micaela; Apollonio, Francesca
2013-11-01
Water self-diffusion and the dipolar response of the selectivity filter within human aquaporin 4 have been studied using molecular dynamics (MD) simulations in the absence and presence of pulses of external static and alternating electric fields. The pulses were approximately 50 and 100 ns in duration and 0.0065 V/Å in (r.m.s.) intensity and were either static or else 2.45 or 100 GHz in frequency and applied both along and perpendicular to the channels. In addition, the relaxation of the aquaporin, water self-diffusion and gating dynamics following cessation of the impulses was studied. In previous work it was determined that switches in the dihedral angle of the selectivity filter led to boosting of water permeation events within the channels, in the presence of identical external static and alternating electric fields, although applied continuously. Here the application of field impulses (and subsequently, upon removal) has shown that it is the dipolar orientation of the histidine-201 residue in the selectivity filter which governs the dihedral angle, and hence influences water self-diffusion; this constitutes an appropriate order parameter. The dipolar response of this residue to the applied field leads to the adoption of four distinct states, which we modelled as time-homogeneous Markov jump processes, and may be distinguished in the potential of mean force (PMF) as a function of the dipolar orientation of histidine-201. The observations of enhanced "dipolar flipping" of H201 serve to explain increased levels of water self-diffusion within aquaporin channels during, and immediately following, field impulses, although the level of statistical certainty here is lower. Given the appreciable size of the energy barriers evident in PMFs computed directly from deterministic MD (whether in the absence or presence of external fields), metadynamics calculations were undertaken to explore the free-energy landscape of histidine-201 orientation with greater accuracy and
Reale, Riccardo; English, Niall J; Garate, José-Antonio; Marracino, Paolo; Liberti, Micaela; Apollonio, Francesca
2013-11-28
Water self-diffusion and the dipolar response of the selectivity filter within human aquaporin 4 have been studied using molecular dynamics (MD) simulations in the absence and presence of pulses of external static and alternating electric fields. The pulses were approximately 50 and 100 ns in duration and 0.0065 V/Å in (r.m.s.) intensity and were either static or else 2.45 or 100 GHz in frequency and applied both along and perpendicular to the channels. In addition, the relaxation of the aquaporin, water self-diffusion and gating dynamics following cessation of the impulses was studied. In previous work it was determined that switches in the dihedral angle of the selectivity filter led to boosting of water permeation events within the channels, in the presence of identical external static and alternating electric fields, although applied continuously. Here the application of field impulses (and subsequently, upon removal) has shown that it is the dipolar orientation of the histidine-201 residue in the selectivity filter which governs the dihedral angle, and hence influences water self-diffusion; this constitutes an appropriate order parameter. The dipolar response of this residue to the applied field leads to the adoption of four distinct states, which we modelled as time-homogeneous Markov jump processes, and may be distinguished in the potential of mean force (PMF) as a function of the dipolar orientation of histidine-201. The observations of enhanced "dipolar flipping" of H201 serve to explain increased levels of water self-diffusion within aquaporin channels during, and immediately following, field impulses, although the level of statistical certainty here is lower. Given the appreciable size of the energy barriers evident in PMFs computed directly from deterministic MD (whether in the absence or presence of external fields), metadynamics calculations were undertaken to explore the free-energy landscape of histidine-201 orientation with greater accuracy and
NASA Astrophysics Data System (ADS)
Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan
2016-11-01
An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.
NASA Astrophysics Data System (ADS)
Kulyk, B.; Essaidi, Z.; Luc, J.; Sofiani, Z.; Boudebs, G.; Sahraoui, B.; Kapustianyk, V.; Turko, B.
2007-12-01
We report the preparation of microcrystalline ZnO thin films on sapphire substrates using a simple method based on the thermal evaporation of metallic Zn in vacuum with further annealing process. The aim of annealing in the oxygen atmosphere in the range of 800-850°C was to obtain the high quality ZnO films. The surface morphology was studied by scanning electron microscopy and atomic force microscopy. The polycrystalline films with ZnO microrods at different stages of their growth were investigated. Second and third harmonic generation measurements were performed by means of the rotational Maker fringe technique using Nd:YAG laser at 1064nm in picosecond regime. The obtained values of second and third order nonlinear susceptibilities were found to be high enough for the potential applications of the investigated materials in the optical switching devices based on refractive index changes.
NASA Astrophysics Data System (ADS)
Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Mohan Kumar, R.; Umarani, P. R.
2015-01-01
An organic nonlinear optical bulk single crystal, Ammonium 3-carboxy-4-hydroxy benzenesulfonate monohydrate (ACHBS) was successfully grown by solution growth technique. Single crystal X-ray diffraction study confirms that, the grown crystal belongs to P21/c space group. Powder X-ray diffraction and high resolution X-ray diffraction analyses revealed the crystallinity of the grown crystal. Infrared spectral analysis showed the vibrational behavior of chemical bonds and its functional groups. The thermal stability and decomposition stages of the grown crystal were studied by TG-DTA analysis. UV-Visible transmittance studies showed the transparency region and cut-off wavelength of the grown crystal. The third-order nonlinear optical susceptibility of the grown crystal was estimated by Z-scan technique using Hesbnd Ne laser source. The mechanical property of the grown crystal was studied by using Vicker's microhardness test.
On the Trellis structure of a (64,40,8) subcode of the (64,42,8) third-order Reed-Muller code
NASA Technical Reports Server (NTRS)
Moorthy, Hari T.; Lin, Shu; Uehara, Gregory
1995-01-01
A (64,40,8) subcode of the (64,42,8) third-order Reed-Muller code is proposed to NASA for high-speed satellite communications. This code can be either used alone or used as an inner-code in a concatenated coding system with the NASA standard (255,223,33) Reed-Solomon code as the outer code to achieve high performance with reduced decoding complexity. This Reed-Muller subcode has a relatively simple and parallel trellis structure and consequently can be decoded with a group of identical and relatively simple Viterbi decoders in parallel to achieve high-speed decoding. In this report, the complexities of various sectionalized trellis diagrams are analyzed. Based on this analysis, the trellis diagram with the smallest overall complexity will be used for the implementation of a high-speed decoder.
NASA Astrophysics Data System (ADS)
Feng, L.; Wang, Y. L.; Ren, Q.; Zhang, G. H.; Yang, H. L.; Sun, X. B.
A novel dmit2- salt: (hexadecyltrimethylammonium)bis(4,5-dithiolato-1,3-dithiole-2-thione)copper, abbreviated as HTCu, is synthesized and characterized for third-order optical nonlinearity by Z-scan technique at a wavelength of 1064 nm with laser duration of 30 ps. Z-scan spectra reveal a negative Kerr coefficient at 1064 nm and no nonlinear absorption was observed under this condition. The nonlinear refraction coefficient n2 and the second hyperpolarizability γ have been determined to be -1.51 × 10-11 and 1.36 × 10-30 esu, respectively, suggesting HTCu is a promising material for all-optical switching.
NASA Astrophysics Data System (ADS)
Lefrancois, Daniel; Rehn, Dirk R.; Dreuw, Andreas
2016-08-01
For the calculation of adiabatic singlet-triplet gaps (STG) in diradicaloid systems the spin-flip (SF) variant of the algebraic diagrammatic construction (ADC) scheme for the polarization propagator in third order perturbation theory (SF-ADC(3)) has been applied. Due to the methodology of the SF approach the singlet and triplet states are treated on an equal footing since they are part of the same determinant subspace. This leads to a systematically more accurate description of, e.g., diradicaloid systems than with the corresponding non-SF single-reference methods. Furthermore, using analytical excited state gradients at ADC(3) level, geometry optimizations of the singlet and triplet states were performed leading to a fully consistent description of the systems, leading to only small errors in the calculated STGs ranging between 0.6 and 2.4 kcal/mol with respect to experimental references.
Lefrancois, Daniel; Rehn, Dirk R; Dreuw, Andreas
2016-08-28
For the calculation of adiabatic singlet-triplet gaps (STG) in diradicaloid systems the spin-flip (SF) variant of the algebraic diagrammatic construction (ADC) scheme for the polarization propagator in third order perturbation theory (SF-ADC(3)) has been applied. Due to the methodology of the SF approach the singlet and triplet states are treated on an equal footing since they are part of the same determinant subspace. This leads to a systematically more accurate description of, e.g., diradicaloid systems than with the corresponding non-SF single-reference methods. Furthermore, using analytical excited state gradients at ADC(3) level, geometry optimizations of the singlet and triplet states were performed leading to a fully consistent description of the systems, leading to only small errors in the calculated STGs ranging between 0.6 and 2.4 kcal/mol with respect to experimental references.
NASA Astrophysics Data System (ADS)
Kong, Ming; Liu, Yanqiu; Wang, Hui; Luo, Junshan; Li, Dandan; Zhang, Shengyi; Li, Shengli; Wu, Jieying; Tian, Yupeng
2015-01-01
Four novel Zn(II) terpyridine complexes (ZnLCl2, ZnLBr2, ZnLI2, ZnL(SCN)2) based on carbazole derivative group were designed, synthesized and fully characterized. Their photophysical properties including absorption and one-photon excited fluorescence, two-photon absorption (TPA) and optical power limiting (OPL) were further investigated systematically and interpreted on the basis of theoretical calculations (TD-DFT). The influences of different solvents on the absorption and One-Photon Excited Fluorescence (OPEF) spectral behavior, quantum yields and the lifetime of the chromophores have been investigated in detail. The third-order nonlinear optical (NLO) properties were investigated by open/closed aperture Z-scan measurements using femtosecond pulse laser in the range from 680 to 1080 nm. These results revealed that ZnLCl2 and ZnLBr2 exhibited strong two-photon absorption and ZnLCl2 showed superior optical power limiting property.
Okcan, Burak; Gielen, Georges; Van Hoof, Chris
2012-02-01
This paper presents a third-order switched-capacitor sigma-delta modulator implemented in a standard 0.35-μm CMOS process. It operates from 300 K down to 4.2 K, achieving 70.8 dB signal-to-noise-plus-distortion ratio (SNDR) in a signal bandwidth of 5 kHz with a sampling frequency of 500 kHz at 300 K. The modulator utilizes an operational transconductance amplifier in its loop filter, whose architecture has been optimized in order to eliminate the cryogenic anomalies below the freeze-out temperature. At 4.2 K, the modulator achieves 67.7 dB SNDR consuming 21.17 μA current from a 3.3 V supply.
NASA Astrophysics Data System (ADS)
Okcan, Burak; Gielen, Georges; Van Hoof, Chris
2012-02-01
This paper presents a third-order switched-capacitor sigma-delta modulator implemented in a standard 0.35-μm CMOS process. It operates from 300 K down to 4.2 K, achieving 70.8 dB signal-to-noise-plus-distortion ratio (SNDR) in a signal bandwidth of 5 kHz with a sampling frequency of 500 kHz at 300 K. The modulator utilizes an operational transconductance amplifier in its loop filter, whose architecture has been optimized in order to eliminate the cryogenic anomalies below the freeze-out temperature. At 4.2 K, the modulator achieves 67.7 dB SNDR consuming 21.17 μA current from a 3.3 V supply.
Sivasubramani, V.; Pandian, Muthu Senthil Ramasamy, P.
2016-05-23
2-amino-5-nitropyridinium nitrate (2A5NPN) is a semi-organic nonlinear optical crystal and optically good quality 2A5NPN single crystals were successfully grown by slow evaporation solution growth technique (SEST) at ambient temperature. The crystallographic structure of the grown crystal was determined by single crystal X-Ray diffraction analysis and it belongs to Monoclinic crystal system with centro symmetric crystalline nature. The crystallinity of the grown crystal was confirmed by powder X-ray diffraction analysis. The other physical properties of grown crystals are also characterized using TG-DTA, UV-Visible NIR, chemical etching, photoconductivity and Z-scan measurements. The Z-scan method reveals that the 2A5NPN crystal possesses multi photon absorption behaviour and the significantly higher third order susceptibility and it is a promising potential NLO material.
NASA Astrophysics Data System (ADS)
Htwe, Zin Maung; Zhang, Yun-Dong; Yao, Cheng-Bao; Li, Hui; Li, Han-Yang; Yuan, Ping
2016-02-01
We report the investigation of third order nonlinear optical properties of undoped zinc oxide and indium doped zinc oxide thin films using nanosecond (6 ns, 18 μJ at 532 nm) Z-scan technique. Undoped (ZnO) and indium doped zinc oxide (InZnO) thin films were synthesized on quart silica substrate by using radio frequency (RF) magnetron sputtering technique. The structural and characterization of deposited thin films were analyzed by X-ray diffraction (XRD). In XRD results show different behaviors as amorphous oxide semiconductor and polycrystalline oxide semiconductor for ZnO and InZnO thin films respectively. Elemental compositions of thin films were analyzed by energy dispersive spectrometer (EDS). Surface morphology of ZnO and InZnO films were measured by using scanning electron microscopy (SEM), which show uniform and regular surface with small grain size distribution. Linear optical transmission and reflection thin films were analyzed by UV-VIS spectrometer. The UV-VIS results reveal that the optical transmittances of deposited thin films were increased after doping indium. The third order nonlinear optical properties of ZnO and InZnO thin films were carried out using nanosecond (6 ns) laser Z-scan technique at 532 nm wavelength. In open aperture case, both ZnO and InZnO thin films are show reverse saturable absorption (RSA) behaviors. For close-aperture Z-scan, the transmittance curve of ZnO thin film occurs as valley-peak (positive nonlinear refraction) characteristic, which indicates self-focusing behavior.
NASA Astrophysics Data System (ADS)
Senthil, K.; Kalainathan, S.; Hamada, F.; Yamada, M.; Aravindan, P. G.
2015-08-01
the grown crystals. Its third-order nonlinear optical properties were investigated by Z-scan technique and proved that the 4MSTB crystal possesses two-photon absorptions (TPA) and the self-defocusing effect. The second-order molecular hyperpolarizability (γ) value at 632.8 nm is calculated to be 3.555 × 10-34 esu. The photoconductivity study of 4MSTB reveals that the negative photoconducting nature. The obtained all the results in the present work are making a 4MSTB promising candidate for the possible applications in optical switches, optical power limiter, and non-linear optical applications.
Fischer, Sean A.; Ueltschi, Tyler W.; El-Khoury, Patrick Z.; ...
2015-07-29
Carbon-hydrogen (C-H) vibration modes serve as key probes in the chemical identification of hydrocarbons and in vibrational sum-frequency generation (SFG) spectroscopy of hydrocarbons at the liquid/gas interface. Their assignments pose a challenge from a theoretical viewpoint. Here in this work, we present a detailed study of the C-H stretching region of dimethyl sulfoxide (DMSO) using a new Gaussian basis set- based ab initio molecular dynamics (AIMD) module that we have implemented in the NWChem computational chemistry program. By combining AIMD simulations and static normal mode analysis, we interpret experimental infrared and Raman spectra and explore the role of anharmonic effectsmore » in this system. Our anharmonic normal mode analysis of the in-phase and out-of-phase symmetric C-H stretching modes challenges the previous experimental assignment of the shoulder in the symmetric C-H stretching peak as an overtone or Fermi resonance. In addition, our AIMD simulations also show significant broadening of the in-phase symmetric C-H stretching resonance, which suggests that the experimentally observed shoulder is due to thermal broadening of the symmetric stretching resonance.« less
Fischer, Sean A.; Ueltschi, Tyler W.; El-Khoury, Patrick Z.; Mifflin, Amanda L.; Hess, Wayne P.; Wang, Hong-Fei; Cramer, Christopher J.; Govind, Niranjan
2015-07-29
Carbon-hydrogen (C-H) vibration modes serve as key probes in the chemical identification of hydrocarbons and in vibrational sum-frequency generation (SFG) spectroscopy of hydrocarbons at the liquid/gas interface. Their assignments pose a challenge from a theoretical viewpoint. Here in this work, we present a detailed study of the C-H stretching region of dimethyl sulfoxide (DMSO) using a new Gaussian basis set- based ab initio molecular dynamics (AIMD) module that we have implemented in the NWChem computational chemistry program. By combining AIMD simulations and static normal mode analysis, we interpret experimental infrared and Raman spectra and explore the role of anharmonic effects in this system. Our anharmonic normal mode analysis of the in-phase and out-of-phase symmetric C-H stretching modes challenges the previous experimental assignment of the shoulder in the symmetric C-H stretching peak as an overtone or Fermi resonance. In addition, our AIMD simulations also show significant broadening of the in-phase symmetric C-H stretching resonance, which suggests that the experimentally observed shoulder is due to thermal broadening of the symmetric stretching resonance.
Fischer, Sean A; Ueltschi, Tyler W; El-Khoury, Patrick Z; Mifflin, Amanda L; Hess, Wayne P; Wang, Hong-Fei; Cramer, Christopher J; Govind, Niranjan
2016-03-03
Carbon-hydrogen (C-H) vibration modes serve as key probes in the chemical identification of hydrocarbons and in vibrational sum-frequency generation spectroscopy of hydrocarbons at the liquid/gas interface. Their assignments pose a challenge from a theoretical viewpoint. In this work, we present a detailed study of the C-H stretching region of dimethyl sulfoxide using a new ab initio molecular dynamics (AIMD) module that we have implemented in NWChem. Through a combination of AIMD simulations and static normal mode analysis, we interpret experimental infrared and Raman spectra and explore the role of anharmonic effects in this system. Comprehensive anharmonic normal mode analysis of the C-H stretching region casts doubt upon previous experimental assignments of the shoulder on the symmetric C-H stretching peak. In addition, our AIMD simulations also show significant broadening of the in-phase symmetric C-H stretching resonance, which suggests that the experimentally observed shoulder is due to thermal broadening of the symmetric stretching resonance.
Fischer, Sean A.; Ueltschi, Tyler W.; El-Khoury, Patrick Z.; Mifflin, Amanda L.; Hess, Wayne P.; Wang, Hongfei; Cramer, Christopher J.; Govind, Niranjan
2016-03-03
Carbon-hydrogen (C-H) vibration modes serve as key probes in the chemical iden- tication of hydrocarbons and in vibrational sum-frequency generation (SFG) spec- *troscopy of hydrocarbons at the liquid/gas interface. Their assignments pose a chal- lenge from a theoretical viewpoint. In this work, we present a detailed study of the C-H stretching region of dimethyl sulfoxide (DMSO) using a new Gaussian basis set- based ab initio molecular dynamics (AIMD) module that we have implemented in the NWChem computational chemistry program. By combining AIMD simulations and static normal mode analysis, we interpret experimental infrared and Raman spectra and explore the role of anharmonic effects in this system. Our anharmonic normal mode analysis of the in-phase and out-of-phase symmetric C-H stretching modes chal- lenges the previous experimental assignment of the shoulder in the symmetric C-H stretching peak as an overtone or Fermi resonance. In addition, our AIMD simulations also show signicant broadening of the in-phase symmetric C-H stretching resonance, which suggests that the experimentally observed shoulder is due to thermal broadening of the symmetric stretching resonance.
NASA Astrophysics Data System (ADS)
Rustad, James R.; Felmy, Andrew R.; Hay, Benjamin P.
1996-05-01
A new approach to estimating stability constants for proton binding in multisite surface complexation models is presented. The method is based on molecular statics computation of energies for the formation of proton vacancies and interstitials in ideal periodic slabs representing the (100), (110), (010), (001), and (021) surfaces of goethite. Gas-phase energies of clusters representing the hydrolysis products of ferric iron are calculated using the same potential energy functions used for the surface. These energies are linearly related to the hydrolysis constants for ferric iron in aqueous solution. Stability constants for proton binding at goethite surfaces are estimated by assuming the same log K- Δ E relationship for goethite surface protonation reactions. These stability constants predict a pH of zero charge of 8.9, in adequate agreement with measurements on CO 2-free goethite. The estimated stability constants differ significantly from previous estimations based on Pauling bond strength. We find that nearly all the surface oxide ions are reactive; nineteen of the twenty-six surface sites investigated have log Kint between 7.7 and 9.4. This implies a site density between fifteen and sixteen reactive sites/nm for crystals dominated by (110) and (021) crystal faces.
Third-Order Incremental Dual-Basis Set Zero-Buffer Approach for Large High-Spin Open-Shell Systems.
Zhang, Jun; Dolg, Michael
2015-03-10
The third-order incremental dual-basis set zero-buffer approach (inc3-db-B0) is an efficient, accurate, and black-box quantum chemical method for obtaining correlation energies of large systems, and it has been successfully applied to many real chemical problems. In this work, we extend this approach to high-spin open-shell systems. In the open-shell approach, we will first decompose the occupied orbitals of a system into several domains by a K-means clustering algorithm. The essential part is that we preserve the active (singly occupied) orbitals in all the calculations of the domain correlation energies. The duplicated contributions of the active orbitals to the correlation energy are subtracted from the incremental expansion. All techniques of truncating the virtual space such as the B0 approximation can be applied. This open-shell inc3-db-B0 approach is combined with the CCSD and CCSD(T) methods and applied to the computations of a singlet-triplet gap and an electron detachment process. Our approach exhibits an accuracy better than 0.6 kcal/mol or 0.3 eV compared with the standard implementation, while it saves a large amount of the computational time and can be efficiently parallelized.
NASA Technical Reports Server (NTRS)
Xu, Kuan-Man; Cheng, Anning
2010-01-01
This study presents preliminary results from a multiscale modeling framework (MMF) with an advanced third-order turbulence closure in its cloud-resolving model (CRM) component. In the original MMF, the Community Atmosphere Model (CAM3.5) is used as the host general circulation model (GCM), and the System for Atmospheric Modeling with a first-order turbulence closure is used as the CRM for representing cloud processes in each grid box of the GCM. The results of annual and seasonal means and diurnal variability are compared between the modified and original MMFs and the CAM3.5. The global distributions of low-level cloud amounts and precipitation and the amounts of low-level clouds in the subtropics and middle-level clouds in mid-latitude storm track regions in the modified MMF show substantial improvement relative to the original MMF when both are compared to observations. Some improvements can also be seen in the diurnal variability of precipitation.
Vivek, P; Suvitha, A; Murugakoothan, P
2015-01-05
A new semiorganic nonlinear optical material anilinium perchlorate was grown by the slow evaporation technique using water as solvent. The solubility and meta stable zone width were determined. The anilinium perchlorate crystal belongs to orthorhombic system with noncentrosymmetric space group P2₁2₁2₁. The presence of various functional groups was identified by FT-IR FT-Raman spectrum. The morphology of the anilinium perchlorate crystal was studied. From this morphology, anilinium perchlorate crystal plate was cut along three prominent planes, such as (001), (010) and (20-1). The thermal stability of the crystal was determined using TG-DTA studies. The hardness, laser damage threshold, transmittance, reflectance, experimental refractive index of the crystal was found. The particle size dependent second harmonic generation efficiency for anilinium perchlorate was evaluated by Kurtz-Perry powder method using Nd:YAG laser, which established the existence of phase matching. The third order nonlinear refractive index and nonlinear absorption coefficient of the grown crystal were measured by Z-scan studies. Copyright © 2014 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Abraham, N. B.; Matlin, M. D.; Gioggia, R. S.
1996-05-01
Instabilities and dynamical pulsations are common features of solutions of a model that includes the material variable dynamics for a laser with a polarization isotropic resonator and with a homogeneously broadened j=1-->j=0 transition. These resemble in some respects features found in third-order Lamb theories under anisotropic conditions, such as splitting of the optical field into two relatively independent orthogonally polarized modes with different optical frequencies. At higher intensities the amplitudes and frequencies of these modes exhibit such strong coupling that a ``two-mode'' description loses its usefulness or effectiveness. Various periodic attractors with strong intensity and polarization pulsations are found for moderate excitation levels. Some of these attractors preserve the breaking of the polarization isotropy on average just as does any linearly polarized solution. But in some cases the dynamics restore the polarization isotropy on average. We also find other dynamical phenomena, including periodic and apparently chaotic states, often involving rapid switching between long interludes of nearly constant polarization, and homoclinic behavior.
Kim, Hyun Sung; Yoon, Kyung Byung
2012-02-08
The third-order nonlinear optical (3NLO) activity of PbS quantum dots (QDs) encapsulated in zeolite Y has been expected to depend sensitively on the countercation of the zeolite host. However, ion exchange of the pristine countercation, H(+), with other cations has not been possible because the framework decomposes and the QDs aggregate immediately when the PbS QD-incorporating zeolite Y with H(+) as the countercation is exposed to the atmosphere. We now report that when H(+) is transformed to NH(4)(+), the framework of PbS QD-containing zeolite Y does not undergo decomposition and the PbS QDs do not undergo aggregation to form larger QDs during the aqueous ion exchange of NH(4)(+) with alkali-metal ions (M(A)(+) = Li, Na(+), K(+), Rb(+)). The 3NLO activity of the M(A)(+)-exchanged PbS QD-incorporating zeolite Y film increases with increasing size of M(A)(+). The stabilization of the surface-bound exciton by the electron-rich framework oxide and electron-poor cation is proposed to be responsible for the increase. This is the first example of a method for systematically increasing the 3NLO activity of QDs dispersed in a dielectric matrix by systematically changing its properties. These results will serve as a guideline for future research and also promote applications of QD-incorporating zeolites in various fields.
NASA Astrophysics Data System (ADS)
Tamgadge, Y. S.; Pahurkar, V. G.; Talwatkar, S. S.; Sunatkari, A. L.; Muley, G. G.
2015-08-01
We report synthesis, linear and third-order nonlinear optical properties of Cd-doped CuO-PVA nanocomposite thin films. Cd-doped CuO nanoparticles (NPs) were obtained by chemical synthesis method, and spin coating technique was used to obtain thin films in polyvinyl alcohol matrix. X-ray diffraction (XRD) shows formation of crystalline CuO having monoclinic phase with average particle size of 10 nm. Ultraviolet-visible (UV-Vis) spectroscopy attests formation of NPs by witnessing strong blue shift in the excitonic absorption. Absorption wavelength of CuO NPs shifts from 365 to 342 nm for Cd doping of 1-5 wt%. Both XRD and UV-Vis data confirm decrease in particle size with increase in Cd-doping concentration. Thin films have been characterized by Z-scan technique under continuous-wave He-Ne laser, and enhanced values of nonlinear refractive index n 2 and nonlinear absorption coefficient β have been obtained. Enhancements in the nonlinear optical properties have been attributed to the thermal effect due to strong linear absorption coefficient combined with increased thermo-optic coefficient. Contributing mechanisms such as photoacoustic effect, surface states effect and dielectric effect due to dopant and thin film structure have been discussed.
NASA Astrophysics Data System (ADS)
Izsák, Róbert; Neese, Frank
2013-07-01
The 'chain of spheres' approximation, developed earlier for the efficient evaluation of the self-consistent field exchange term, is introduced here into the evaluation of the external exchange term of higher order correlation methods. Its performance is studied in the specific case of the spin-component-scaled third-order Møller--Plesset perturbation (SCS-MP3) theory. The results indicate that the approximation performs excellently in terms of both computer time and achievable accuracy. Significant speedups over a conventional method are obtained for larger systems and basis sets. Owing to this development, SCS-MP3 calculations on molecules of the size of penicillin (42 atoms) with a polarised triple-zeta basis set can be performed in ∼3 hours using 16 cores of an Intel Xeon E7-8837 processor with a 2.67 GHz clock speed, which represents a speedup by a factor of 8-9 compared to the previously most efficient algorithm. Thus, the increased accuracy offered by SCS-MP3 can now be explored for at least medium-sized molecules.
NASA Astrophysics Data System (ADS)
Li, Kang; Tang, Guodong; Kou, ShanShan; Culnane, Lance F.; Zhang, Yu; Song, Yinglin; Li, Rongqing; Wei, Changmei
2015-03-01
Three complexes of M(DPIP)2 (M = Cu, Co, Zn as 1, 2, 3) were synthesized and characterized by elemental analysis, IR, UV-Vis, thermogravimetry, and X-ray diffraction. Their nonlinear optical properties were measured by the Z-scan technique and yielded a normalized transmittance of about 70% for complex 1 (45 μJ pulse), and 93% for complex 3 (68 μJ pulse at the focus point). The nonlinear absorption coefficient, β, is 1.4 × 10-11 m/W for 1 and 5.6 × 10-13 m/W for 3, and the third-order nonlinear refraction index, n2, is 1.0 × 10-18 m2/W for 3. Complex 1 shows self-defocusing property, while complex 3 exhibits self-focusing property. The thermogravimetric results show that the frame structure of compounds 1-3 begin to collapse at 400, 250 and 280 °C, respectively, which suggests that they elicit excellent thermal stability. This research aims to provide better understanding of these compounds, and offer preliminary explanations for the significant differences between compounds 1-3, in order to potentially help in the designing of future novel materials with NLO properties.
NASA Astrophysics Data System (ADS)
Sivakumar, N.; Anbalagan, G.
2016-10-01
Z-scan studies on the grown crystal was investigated by diode-pumped Nd; YAG laser. Nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) values of MLM were found to be -1.0 × 10-8 cm2/W and 1.36 × 10-6 esu respectively. Powder X-ray diffraction analysis depicted that the crystal belongs to monoclinic system with space group P21/c. Birefringence study revealed the optical dispersion behavior of MLM crystal. Linear refractive index on (10-1) plane was measured by prism coupling technique and was estimated to be 1.4705. Hardness study was carried out along three different planes which exhibit hardness anisotropy of 41.11%. Meyer's index values of the grown crystal for the (10-1), (010) and (111) planes were found to be 2.39, 2.61 and 2.04 respectively. Etching studies on the prominent (10-1) growth plane was explained by two dimensional layer growth mechanisms. Photoluminescence study was performed on MLM crystal to explore its efficacy towards optical device fabrications.
NASA Astrophysics Data System (ADS)
Dobeš, Josef; Grábner, Martin; Puričer, Pavel; Vejražka, František; Míchal, Jan; Popp, Jakub
2017-05-01
Nowadays, there exist relatively precise pHEMT models available for computer-aided design, and they are frequently compared to each other. However, such comparisons are mostly based on absolute errors of drain-current equations and their derivatives. In the paper, a novel method is suggested based on relative root-mean-square errors of both drain current and its derivatives up to the third order. Moreover, the relative errors are subsequently relativized to the best model in each category to further clarify obtained accuracies of both drain current and its derivatives. Furthermore, one our older and two newly suggested models are also included in comparison with the traditionally precise Ahmed, TOM-2 and Materka ones. The assessment is performed using measured characteristics of a pHEMT operating up to 110 GHz. Finally, a usability of the proposed models including the higher-order derivatives is illustrated using s-parameters analysis and measurement at more operating points as well as computation and measurement of IP3 points of a low-noise amplifier of a multi-constellation satellite navigation receiver with ATF-54143 pHEMT.
NASA Astrophysics Data System (ADS)
Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Md Zahid, I.; Mohan Kumar, R.; Umarani, P. R.
2015-05-01
Organic Uronium 3-carboxy-4-hydroxybenzenesulfonate (UCHBS) nonlinear optical single crystal was grown by solution growth technique. The solubility and nucleation studies were performed for UCHBS at different temperatures 30, 35, 40, 45, 50 and 55 °C. The crystal structure of UCHBS was elucidated from single crystal X-ray diffraction study. High resolution X-ray diffraction technique was employed to study the perfection and internal defects of UCHBS crystal. Infrared and Raman spectra were recorded to analyze the vibrational behavior of chemical bonds and its functional groups. The physico-chemical changes, stability and decomposition stages of the UCHBS compound were established by TG-DTA studies. The dielectric phenomenon of UCHBS crystal was studied at different temperatures with respect to frequency. Linear optical properties of transmittance, cut-off wavelength, band gap of UCHBS were found from UV-visible spectral studies. Third-order nonlinear optical susceptibility, nonlinear refractive index, nonlinear optical absorption coefficient values were measured by Z-scan technique. The mechanical properties of UCHBS crystal was studied by using Vicker's microhardness test. The growth features of UCHBS crystal were analyzed from etching studies.
NASA Astrophysics Data System (ADS)
Loheac, Andrew C.; Drut, Joaquín E.
2017-05-01
We analyze the pressure and density equations of state of unpolarized nonrelativistic fermions at finite temperature in one spatial dimension with contact interactions. For attractively interacting regimes, we perform a third-order lattice perturbation theory calculation, assess its convergence properties by comparing with hybrid Monte Carlo results (there is no sign problem in this regime), and demonstrate agreement with real Langevin calculations. For repulsive interactions, we present lattice perturbation theory results as well as complex Langevin calculations, with a modified action to prevent uncontrolled excursions in the complex plane. Although perturbation theory is a common tool, our implementation of it is unconventional; we use a Hubbard-Stratonovich transformation to decouple the system and automate the application of Wick's theorem, thus generating the diagrammatic expansion, including symmetry factors, at any desired order. We also present an efficient technique to tackle nested Matsubara frequency sums without relying on contour integration, which is independent of dimension and applies to both relativistic and nonrelativistic systems, as well as all energy-independent interactions. We find exceptional agreement between perturbative and nonperturbative results at weak couplings, and furnish predictions based on complex Langevin at strong couplings. We additionally present perturbative calculations of up to the fifth-order virial coefficient for repulsive and attractive couplings. Both the lattice perturbation theory and complex Langevin formalisms can easily be extended to a variety of situations including polarized systems, bosons, and higher dimension.
Prager, Stefan; Zech, Alexander; Wesolowski, Tomasz A; Dreuw, Andreas
2017-10-10
Implementation, benchmarking, and representative applications of the new FDE-ADC(3) method for describing environmental effects on excited states as a combination of frozen density embedding (FDE) and the algebraic-diagrammatic construction scheme for the polarization propagator of third order (ADC(3)) are presented. Results of FDE-ADC(3) calculations are validated with respect to supersystem calculations on test systems with varying molecule-environment interaction strengths from dispersion up to multiple hydrogen bonds. The overall deviation compared to the supersystem calculations is as small as 0.029 eV for excitation energies, which is even smaller than the intrinsic error of ADC(3). The dependence of the accuracy on the choice of method and functional for the calculation of the environment and the nonelectrostatic part of the system-environment interaction is evaluated. In three representative examples, the FDE-ADC method is applied to investigate larger systems and to analyze excited state properties using visualization of embedded densities and orbitals.
Tanizawa, Ken; Kurosu, Takayuki; Namiki, Shu
2010-05-10
A wideband and fast tunable chromatic dispersion compensator is one of the key components for the future high-speed optical transmissions. We have so far proposed and demonstrated a new tunable dispersion compensation scheme called parametric tunable dispersion compensator (P-TDC), which is based on the combination of parametric frequency conversion and frequency dependent dispersive media. The P-TDC has many attractive features such as a seamlessly wideband operation, wide tunable range and fast dispersion tuning. In fact, with appropriate configurations of dispersive media, the P-TDC can compensate the dispersion slope of transmission fibers even though the second-order dispersion is small. In this paper, we use such a P-TDC scheme and successfully achieve high-speed optical transmissions over a second- and third-order dispersion managed dispersion shifted fiber (DSF) span. The transmission experiments show low-penalty 172 Gbit/s return-to-zero on-off-keying transmissions over 126-km DSF. (c) 2010 Optical Society of America.
NASA Technical Reports Server (NTRS)
Wang, Shouping; Wang, Qing
1994-01-01
This study focuses on the effects of drizzle in a one-dimensional third-order turbulence closure model of the nocturnal stratus-topped marine boundary layer. When the simulated drizzle rate is relatively small (maximum approximately equal to 0.6 mm/day), steady-state solutions are obtained. The boundary layer stabilizes essentially because drizzle causes evaporative cooling of the subcloud layer. This stabilization considerably reduces the buoyancy flux and turbulence kinetic energy below the stratus cloud. Thus, drizzle tends to decouple the cloud from the subcloud layer in the model, as suggested by many observational studies. In addition, the evaporation of drizzle in the subcloud layer creates small scattered clouds, which are likely to represent cumulus clouds, below the solid stratus cloud in the model. The sensitivity experiments show that these scattered clouds help maintain a coupled boundary layer. When the drizzle rate is relatively large (maximum approximately equal to 0.9 mm/day), the response of the model becomes transient with bursts in turbulent fluxes. This phenomenon is related to the formation of the scattered cloud layer below the solid stratus cloud. It appears that the model is inadequate to represent the heat and moisture transport by strong updrafts covering a small fractional area in cumulus convection.