Diatomic–diatomic molecular collision integrals for pressure broadening and Dicke narrowing: A generalization of Hess’s theory

1986 ◽  
Vol 85 (2) ◽  
pp. 713-718 ◽  
Author(s):  
L. Monchick ◽  
L. W. Hunter
Keyword(s):  
Pressure Broadening ◽  
Collision Integrals ◽  
Molecular Collision

scholarly journals SOME MOLECULAR COLLISION INTEGRALS FOR POINT ATTRACTION AND REPULSION POTENTIALS

1956 ◽  
Vol 42 (8) ◽  
pp. 546-559 ◽  
Author(s):  
M. A. Eliason ◽  
D. E. Stogryn ◽  
J. O. Hirschfelder
Keyword(s):  
Collision Integrals ◽  
Molecular Collision

SOME MOLECULAR COLLISION INTEGRALS FOR POINT ATTRACTION AND REPULSION POTENTIALS

1956 ◽  
Author(s):  
M. A. ELIASON ◽  
D. E. STOGRYN ◽  
J. O. HIRSCHFELDER
Keyword(s):  
Collision Integrals ◽  
Molecular Collision

scholarly journals Analytical angular solutions for the atom–diatom interaction potential in a basis set of products of two spherical harmonics: two approaches

2021 ◽  
Author(s):  
Mariusz Pawlak ◽  
Marcin Stachowiak
Keyword(s):  
Spherical Harmonics ◽  
Interaction Potential ◽  
Chem Phys ◽  
Basis Set ◽  
Matrix Elements ◽  
Trigonometric Functions ◽  
Variational Theory ◽  
Molecular Collision ◽  
The Matrix ◽  
Analytical Expressions

AbstractWe present general analytical expressions for the matrix elements of the atom–diatom interaction potential, expanded in terms of Legendre polynomials, in a basis set of products of two spherical harmonics, especially significant to the recently developed adiabatic variational theory for cold molecular collision experiments [J. Chem. Phys. 143, 074114 (2015); J. Phys. Chem. A 121, 2194 (2017)]. We used two approaches in our studies. The first involves the evaluation of the integral containing trigonometric functions with arbitrary powers. The second approach is based on the theorem of addition of spherical harmonics.

scholarly journals The Time Dependence of the Phases of the Harmonics Relative to the 1490 sec Fundamental in PG1346+082

1989 ◽  
Vol 114 ◽  
pp. 296-299
Author(s):  
J. L. Provencal ◽  
J. C. Clemens ◽  
G. Henry ◽  
B. P. Hine ◽  
R. E. Nather ◽  
...  
Keyword(s):  
White Dwarf ◽  
Compact Object ◽  
Detailed Knowledge ◽  
Line Profiles ◽  
Pressure Broadening ◽  
Dwarf Stars ◽  
White Dwarf Stars ◽  
Adequate Understanding ◽  
Magnitude Variation ◽  
Hydrogen Lines

White dwarf stars provide important boundary conditions for the understanding of stellar evolution. An adequate understanding of even these simple stars is impossible without detailed knowledge of their interiors. PG1346+082, an interacting binary white dwarf system, provides a unique opportunity to view the interior of one degenerate as it is brought to light in the accretion disk of the second star as the primary strips material from its less massive companion (see Wood et at. 1987).PG1346+082 is a photometric variable with a four magnitude variation over a four to five day quasi-period. A fast Fourier transform (FFT) of the light curve shows a complex, time-dependent structure of harmonics. PG1346+082 exhibits flickering – the signature of mass transfer. The optical spectra of the system contain weak emission features during minimum and broad absorption at all other times. This could be attributed to pressure broadening in the atmosphere of a compact object, or to a combination of pressure broadening and doppler broadening in a disk surrounding the compact accretor. No hydrogen lines are observed and the spectra are dominated by neutral helium. The spectra also display variable asymmetric line profiles.

Non-Lorentzian Shape of the Depolarized Rayleigh Line and the Correlation Function of the Tensor Polarization

1973 ◽  
Vol 28 (9) ◽  
pp. 1385-1388
Author(s):  
S. Hess ◽  
H. Vestner
Keyword(s):  
Distribution Function ◽  
Correlation Function ◽  
Rayleigh Line ◽  
Tensor Polarization ◽  
Pressure Broadening ◽  
Exponential Functions ◽  
Linear Molecules ◽  
Lorentzian Shape

The correlation function of the tensor polarization relevant for the depolarized Rayleigh line of a gas of rotating linear molecules is calculated for the pressure broadening regime. Point of depar­ture is the Waldmann-Snider equation for the distribution function of the gas. Due to the collisional coupling between the tensor polarization and other moments of the distribution function the cor­relation function turns out to be a sum of exponential functions. Consequently the depolarized Rayleigh line has a non-Lorentzian shape.

Broadening of the Fine-Structure Raman Lines in Gaseous Oxygen

1971 ◽  
Vol 26 (10) ◽  
pp. 1639-1643
Author(s):  
S. Hess ◽  
H. F. P. Knaap
Keyword(s):  
Fine Structure ◽  
Relaxation Frequency ◽  
Collision Term ◽  
60 Ghz ◽  
Pressure Broadening ◽  
Gaseous Oxygen ◽  
Molecular Potential ◽  
Electronic Spin ◽  
Anti Stokes ◽  
Rayleigh Light

Abstract Due to the coupling between the rotational angular momentum and the electronic spin, the depolarized Rayleigh light scattered from gaseous oxygen shows Stokes and anti-Stokes satellites shifted by about 60 GHz. The broadening of these fine-structure Raman lines is investigated theoretically for high and medium pressures where the linewidth is determined by two contributions, one proportional and the other inversely proportional to the pressure, p. The linewidth in the pressure broadening region is given by a relaxation frequency which is obtained from the Waldmann-Snider collision term. The p-1 contribution to the linewidth is determined by the ratio of the second moment of the fine-structure freqencies (with respect to the center of the shifted line) and another relaxation frequency. Both relaxation frequencies are sensitive to the nonspherical part of the inter-molecular potential.

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