Showing papers on "Hyperpolarizability published in 1976"
TL;DR: In this paper, the second order hyperpolarizability β has been measured for ortho-, meta-and para-nitroanaline, and anomalously large nonlinearities which can be quantitatively understood as due to the strong donor-acceptor charge transfer interaction.
146 citations
TL;DR: In this paper, a brief summary of the general theory of the long-range potential energy between two molecules, previously developed by Buckingham, is presented, and detailed expressions of this potential energy are given for the three following molecular pairs: tetrahedral molecule-atom, tetrasmolecular molecule-linear molecule, and tetrasnadecapole molecule.
Abstract: A brief summary of the general theory of the long-range potential energy between two molecules, previously developed by Buckingham, is first presented. Then the first detailed expressions of this potential energy are given for the three following molecular pairs : tetrahedral molecule-atom, tetrahedral molecule-linear molecule and tetrahedral molecule-tetrahedral molecule. These expressions are applied to the calculation of the spectral moments of the far infra-red pressure induced absorption band, the second virial coefficient and the intermolecular mean square torque. This allows a discussion of the magnitude of the various terms contributing to this potential energy and leads to a determination, for CH4, of the octupole and hexadecapole moments, and of the hyperpolarizability:
92 citations
TL;DR: In this paper, the second order β and third order γ hyperpolarizabilities of the PBLG polypeptide α-helix were measured and the decay time of the generated harmonic was directly determined and found to be τ=5.0 msec which is consistent with Kerr and dielectric experiments.
Abstract: We have measured the second order β and third order γ hyperpolarizabilities of the PBLG polypeptide α‐helix and find it to have an extremely large nonlinearity. The decay time of the generated harmonic has been directly determined and found to be τ=5.0 msec which is consistent with Kerr and dielectric experiments. The nonlinear saturation at large static fields has been observed and is in quantitative agreement with theory.
77 citations
TL;DR: In this article, the second order hyperpolarizability of the classic pyridine-I2 charge transfer complex dissolved in benzene has been measured using the technique of electric field induced second harmonic generation in solution.
Abstract: The second order hyperpolarizability β for the classic pyridine–I2 charge transfer complex dissolved in benzene has been measured using the technique of electric field induced second harmonic generation in solution. The measured β was found to be very large, being in fact ∼30 times larger than β for pyridine. By using Mulliken’s charge transfer theory for the ground and excited state wavefunctions and substituting them into the quantum mechanical expression for β we were able to accurately account for the experimental results.
25 citations
TL;DR: In this paper, a theory is developed which enumerates all significant single-molecule and pair contributions to the scattering cross section involving various hyperpolarizability tensors.
Abstract: A recent measurement by Holzer and Ouillon of the symmetry‐forbidden Raman bands ν3(F1u) and ν6(F2u) of gaseous SF6 reveals a pressure dependence of the scattering cross section, i.e., the scattering process involves pairs of colliding molecules. The conventional Raman selection rule which holds for the ordinary dipolar polarizability, is violated by higher‐multipolar (so called hyper‐)polarizabilities. A theory is developed which enumerates all significant single‐molecule and pair contributions to the scattering cross section involving various hyperpolarizability tensors. Numerical values of the latter quantities are determined by comparison with experiment. Analysis of forbidden Raman bands can thus be used as a source of information on higher‐multipolar optical response functions.
22 citations
TL;DR: In this article, a fully coupled variational formulation has been presented for calculating the electric dipole hyperpolarizability (γ) of open and closed-shell atomic systems, for the Li sequence the open-shell formalism of Roothaan has been adopted.
Abstract: A fully coupled variational formulation has been presented for calculating the electric dipole hyperpolarizability (γ) of open and closed-shell atomic systems. For the Li sequence the open-shell formalism of Roothaan has been adopted. The sign of γ for ions of the Li sequence agree well with earlier results although the magnitude for Li atom is somewhat smaller. The value of γ for the Be atom has been found to agree fairly well with other results, both in the order of magnitude and sign, while for B+ and C++ the sign is found to be negative.
17 citations
TL;DR: In this paper, Coupled Hartree-Fock perturbation theory is employed to compute electric dipole hyperpolarizabilities of water, ammonia and methane with three different GTO basis sets.
10 citations
TL;DR: In this paper, the dipole interaction model was used to determine the polarizability and hyperpolarizability derivatives for the ν8 fundamental of CH3CN, and the criteria for the internal standard method were discussed quantitatively.
Abstract: Raman intensities were observed at various concentrations. The observed lines were: the ν8 line of CH3CN (in CCl4 and CH3I), the ν3 line of CH3I (in CCl4), and the ν2 line of CHCl3 (in CCl4). Even after the elimination of the local-field effect, the Raman intensities showed concentration dependencies. The observed solvent effects were explained quantitatively by the use of the dipole interaction model. The polarizability and hyperpolarizability derivatives were determined for the ν8 fundamental of CH3CN. The criteria for the internal standard method were discussed quantitatively.
3 citations