Showing papers on "Hyperpolarizability published in 1979"
TL;DR: In this paper, an all-valence-electron self-consistent field linear-combination of atomic-orbitals molecular-orbital procedure including configuration interactions for calculating the magnitude and sign of the nonlinear second-order molecular susceptibility components (hyperpolarizability) for substituted dipolar aromatic molecular systems is reported.
Abstract: An all-valence-electron self-consistent-field linear-combination-of-atomic-orbitals molecular-orbital procedure including configuration interactions for calculating the magnitude and sign of the nonlinear second-order molecular susceptibility components (hyperpolarizability) for substituted dipolar aromatic molecular systems is reported. Three fundamentally important examples, aniline, nitrobenzene, and $p$-nitroaniline, are considered. Analysis of the microscopic origin of their molecular second-order susceptibilities provides a direct means for understanding the macroscopic nonlinear optical response of organic molecular solids which have already been observed to possess exceptional nonlinear optical properties. The important excited states of aniline, nitrobenzene, and $p$-nitroaniline have been identified and examined in their relationship with the molecular second-order susceptibility-tensor components ${\ensuremath{\beta}}_{\mathrm{ijk}}$. The detailed nature of the charge separation accompanying these states has been discussed in terms of both the configurations composing the excited states, and also the one-electron molecular orbitals which determine those configurations. These results demonstrate how the bond-additivity approximation is inappropriate for $p$-nitroaniline. Finally, the frequency dependence of the ${\ensuremath{\beta}}_{\mathrm{ijk}}$ components in each case shows that the Kleinman relations are valid approximations only at relatively low frequencies.
356 citations
TL;DR: In this article, the Hartree-Fock theory is used as a zeroth-order approximation, with correlation included by using the linked-diagram expansion and many-body perturbation theory, that includes single, double and quadruple excitation diagrams.
Abstract: Static polarizabilities and hyperpolarizabilities for molecules are investigated at the correlated level. The finite-field, coupled Hartree-Fock theory is used as a zeroth-order approximation, with correlation included by using the linked-diagram expansion and many-body perturbation theory, that includes single, double, and quadruple excitation diagrams. The theory is illustrated by studying the hydrogen fluoride molecule. It is demonstrated that the correlation effect for the hyperpolarizabilities $\stackrel{\ensuremath{\leftrightarrow}}{\ensuremath{\beta}}$ and $\stackrel{\ensuremath{\leftrightarrow}}{\ensuremath{\gamma}}$ can be quite large. The average polarizability and dipole moment of HF are in excellent agreement with experiment. The relative importance of the various types of diagrams contributing to electric field properties are discussed. The dependence of the computed hyperpolarizability on basis sets is also investigated.
175 citations
TL;DR: In this article, the authors used SCF and CI wavefunctions of the properties of methane to calculate octopole and hexa-decapole moments, the polarizability, hyperpolarizability and dipole-quadrupole polarizer, diamagnetic contributions to the nuclear magnetic shielding constants, and magnetizability.
Abstract: Accurate calculations are made using SCF and CI wavefunctions of the properties of methane The properties considered are the octopole and hexa-decapole moments, the polarizability, hyperpolarizability and dipole-quadrupole polarizability, the diamagnetic contributions to the nuclear magnetic shielding constants, and to the magnetizability, and the electric field gradient at the hydrogen nucleus Where accurate experimental values are known these are found to be in excellent agreement with the ab initio values The accuracy of determining multipole moments and polarizabilities from collision induced spectra is discussed
121 citations
TL;DR: In this article, a finite field perturbated INDO scheme was used to compute molecular hyperpolarizabilities, to discriminate through simple symmetry considerations between respective σ and π electronic contributions, and to test these ideas on smaller size benzene monosubstitutes.
Abstract: In Parts I and II of this series, we have made use of a finite field perturbated INDO scheme to compute molecular hyperpolarizabilities, to discriminate through simple symmetry considerations between respective σ and π electronic contributions, and to test these ideas on smaller size benzene monosubstitutes. Following the same approach, we report here investigation of a family of disubstituted donor–acceptor benzenes of increasing molecular size [NH2–C6H4– (CH=CH)n−NO2, with n=0,1 and 2] and of great experimental interest in nonlinear optics (second harmonic generation). Supposedly responsible for the higher value of the second order hyperpolarizability (tensor βijk) of this type of molecules, the charge transfer process is explored here and its importance confirmed. Results are compared to experimental data with the help of a simple ’’two level’’ charge transfer model to account for frequency dispersion and found in satisfactory agreement with previously noted tendencies. Also confirmed here are the chai...
111 citations
TL;DR: The pertubation theory based expression for the second-order hyperpolarizability of p -nitroaniline is evaluated by direct summation over CNDO/S generated electronics states.
79 citations
TL;DR: In this paper, a family of benzene monosubstitutes is explored, their mesomeric moments and second order hyperpolarizabilities are seen to account for the donor or acceptor nature of the substituent radical in accordance with a previous model and experiments.
Abstract: Introduced in a one‐electron self‐consistent model (D–C field perturbated INDO Hamiltonian), symmetry considerations exhibit σ and π electron contributions to second order polarizabilities of planar molecules. A family of benzene monosubstitutes is explored, their mesomeric moments and π second order hyperpolarizabilities are seen to account for the donor or acceptor nature of the substituent radical in accordance with a previous model and experiments. Influence of the INDO parametrization is studied for nitrobenzene, where an artificial variation of the oxygen affinity yields a satisfactory value for the benzene third order hyperpolarizability.
62 citations
TL;DR: In this paper, the static polarizabilities and hyperpolarizabilities for the ground states of first row atoms, helium through neon, have been calculated solving the SCF equations of an atom in an electric field by numerical integration of coupled one dimensional differential equations using the Numerov method in matrix form.
Abstract: The static polarizabilities and hyperpolarizabilities for the ground states of first row atoms, helium through neon, have been calculated solving the SCF equations of an atom in an electric field by numerical integration of coupled one dimensional differential equations using the Numerov method in matrix form. The calculated polarizabilities agree within 2% with the values obtained by basis function methods. Heretofore only the hyperpolarizabilities of helium, lithium, beryllium, and neon have been calculated. For helium the hyperpolarizability is in good agreement with previous calculations, whereas for beryllium and neon the values obtained by basis function methods are scattered and significantly lower than the values we obtain. Comparison with experimental results for neon indicates that the Numerical Hartree Fock (NHF) method leads to a better representation of polarized orbitals than the use of basis function methods, which require tedious nonlinear optimization of large basis sets.
54 citations
20 Dec 1979-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this article, the oscillating charge and current distributions induced in matter by a beam of light are expressed in terms of molecular polarizabilities and hyperpolarizabilities, and the symmetry of these property tensors under space and time reversal is examined and methods for their measurement considered.
Abstract: The oscillating charge and current distributions induced in matter by a beam of light are expressed in terms of molecular polarizabilities and hyperpolarizabilities. The symmetry of these property tensors under space and time reversal is examined and methods for their measurement considered. Depolarization of light scattering, optical rotation and differential scattering of right and left circularly polarized light are discussed, as are the effects of vibration and of collisions on the intensities of light scattering. Nonlinear polarization and the measurement of hyperpolarizabilities are briefly examined.
43 citations
TL;DR: In this paper, a simple procedure for choosing adequate gaussian basis sets for molecular hyperpolarizability calculations was presented, and the results showed that the basis sets used in those calculations were inadequate.
40 citations
TL;DR: In this article, the transition polarizabilities for the ν1, ν2 and ν3 fundamentals of methyl iodide and the transition hyperpolarizabilities were obtained for the tensor elements of methyl ionide.
Abstract: Raman intensities of methyl iodide were observed in carbon tetrachloride solution at various concentrations. The observed lines were ν1, ν2, ν3, ν5, and ν6. From the observed data, the transition polarizabilities were determined for the ν1, ν2 and ν3 fundamentals of methyl iodide and the transition hyperpolarizabilities were obtained for the ν3 fundamental of methyl iodide in the form of tensor elements.
1 citations
TL;DR: In this article, the irreducible tensor operators were used to obtain an accurate expression for the macroscopic cubic susceptibility tensor of a homogeneous isotropic medium formed by randomly oriented molecules (liquids and gases).
Abstract: The technique of irreducible tensor operators is used to obtain an accurate expression for the macroscopic cubic susceptibility tensor of a homogeneous isotropic medium formed by randomly oriented molecules (liquids and gases). The result is expressed in terms of the invariants of the molecular hyperpolarizability tensor. Purely rotational and vibrational-rotational molecular transitions are considered. The conditions for maximum intensity of the coherent active Raman (anti-Stokes) spectroscopy (CARS) signal are determined for a finely dispersed medium (crystalline powder). A separate analysis is made of CARS of a noncentrosymmetric crystal powder in which suppression of the cascade process by the quadratic nonlinearity is possible. The first experimental observation of an ARS signal from a finely dispersed sample is reported.