IMPROVED LINE-BROADENING COEFFICIENTS FOR ASYMMETRIC ROTOR MOLECULES WITH APPLICATION TO OZONE LINES BROADENED BY NITROGEN

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 XY(2) molecule (C(2)v symmetry) and a linear, AB, molecule with the XY(2) molecule positioned in the molecule-fixed axes in two different orientations (representations), labeled IIR and IIL, 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 I-R 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 0(3) broadened by N-2 disappear. Further investigation has shown that the variations can be associated with particular quantum state symmetries. Improved agreement with the experimental measurements is observed.