Journal ArticleDOI
The Polarization of Laser Light Scattered by Gases
N. J. Bridge,A. D. Buckingham +1 more
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In this paper, the depolarization of light scattered from the beam of a helium-neon gas laser at low pressures was measured and the results of these measurements were reported.Abstract:
Measurements of the polarization of light scattered from the beam of a helium-neon gas laser at low pressures are described. The intensity, polarization and parallelism of the beam permit high accuracy, and new values for the depolarization ratios of twenty-four simple species are reported. The general quantum theory of scattering is discussed and applied in detail to the evaluation of a formula for the depolarization ratio of the scattered light. It is found that quantum corrections to the classical formula arise from ( i ) the effects of frequency changes due to rotational Raman scattering, ( ii ) changes in the molecular polarizability with rotational state due to centrifugal distortion, ( iii ) approximations inherent in the polarizability scattering formula, and ( iv ) vibrational Raman scattering. Effect ( i ) reduces the depolarization of hydrogen to 91% of its classical value; ( iii ) is unimportant unless the frequency of the light is near an absorption frequency of the molecule. The depolarization measurements have been combined with refractivity data to yield the anisotropies in molecular polarizabilities of the molecules studied.read more
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Molecular Light Scattering and Optical Activity
TL;DR: Using classical and quantum methods with a strong emphasis on symmetry principles, the volume as discussed by the authors develops the theory of varied optical activity and related phenomena from the perspective of molecular scattering of polarized light.
Journal ArticleDOI
Interaction energies of van der Waals and hydrogen bonded systems calculated using density functional theory: Assessing the PW91 model
Seiji Tsuzuki,Hans Peter Lüthi +1 more
TL;DR: In this paper, the performance of density functional theory using the Perdew and Wang's exchange and correlation functionals (PW91) functional for the prediction of intermolecular interactionenergies is evaluated based on calculations on the neon, argon, methane, ethylene, and benzene dimers, as well as on 12 hydrogen bonded complexes.
Journal ArticleDOI
PNO-CI and PNO-CEPA studies of electron correlation effects
TL;DR: In this paper, the authors calculated dipole moments and static dipole polarizabilities for neon and the molecules HF, H2O, NH3, CH4 and CO from SCF and correlated wavefunctions.
Journal ArticleDOI
Electron temperatures in the F region of the ionosphere - Theory and observations
Robert W. Schunk,Andrew F. Nagy +1 more
TL;DR: The theory and observations relating to electron temperatures in the F region of the ionosphere are reviewed in this paper, and a discussion of the various attempts to compare measured and calculated F region electron temperatures.
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Journal ArticleDOI
Influence of Vibration‐Rotation Interaction on Line Intensities in Vibration‐Rotation Bands of Diatomic Molecules
Robert Herman,Richard F. Wallis +1 more
TL;DR: In this article, the influence of vibration-rotation interaction on line intensities in vibration rotation bands of diatomic molecules had been recognized and treated approximately many years ago, and matrix elements have been calculated for the P and R branches of the 0-1, 0-2 and 1-2 transitions taking into account the interaction of rotation and vibration as well as the mechanical and electrical anharmonicity.
Journal ArticleDOI
Die Rotationsstruktur der Ramanbanden mehratomiger Moleküle
G. Placzek,E. Teller +1 more
TL;DR: In this paper, a Reihe von Anwendungen wird diskutiert, aus der Rotationsstruktur der Schwingungsbanden auf Symmetrieeigenschaften und Zuordnung der Schwingsung zu schliesen.