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Improved Line-Broadening Coefficients for Asymmetric Rotor Molecules with Application to Ozone Lines Broadened by Nitrogen

S. Neshyba
R. Gamache
Journal / Anthology

Journal of Quantum Spectroscopy and Radiation Transfer
Year: 1993
Volume: 50
Issue: 5
Page range: 443-453

A procedure for obtaining atom-atom intermolecular potentials from the two-center expansion using symbolic manipulations in FORTRAN and Mathematica on a computer is described. The atom-atom potential for an XY2 molecule (C2v symmetry) and a linear, AB, molecule with the XY2 molecule positioned in the molecule-fixed axes in two different orientations (representations), labeled IIR and II L, are calculated. It has been found that the previous development of the atom-atom potential in the IIR representation is incorrect and leads to a mixed formulation with electrostatic terms in the IR and atom-atom terms in the IIIL representation. Broadening-coefficient calculations presented here show that when the correct potential is used anomalous oscillations in the Ka'=1 transitions for O3 broadened by N2 disappear. Further investigation has shown that the variations can be associated with particular quantum state symmetries. Improved agreement with the experimental measurements is observed.

*Science > Physics > Nuclear and Particle Physics
*Science > Physics > Quantum Physics