Accession Number : ADA282011

Title :   The Atom-Atom Potential in Pressure-Broadened Line Width Calculations for XY2-AB: New Expressions in the II(R), II(L), and I(R) Representations.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS UNIV LOWELL CENTER FOR ATMOSPHERIC RESEARCH

Personal Author(s) : Gamache, R. R. ; Neshyba, S. P.

Report Date : AUG 1993

Pagination or Media Count : 50

Abstract : With the help of symbolic manipulations in FORTRAN and MATHEMATICA, we have computerized the procedure for obtaining atom-atom intermolecular potentials from the two-center expansion. We have calculated the atom-atom potential for an XY2 molecule (C2 sub v symmetry) and a linear, AB molecule with the XY2 molecule positioned in the molecule-fixed axes at three different orientations (representations) labeled I sup R, II sup R, II sup L. We have found that the previous development of the atom-atom potential in the II sup R representation is incorrect, leading to a mixed formulation with electrostatic terms in the I sup R and atom-atom terms in the III sup L representation. Broadening-coefficient calculations presented there 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 symmetries. Improved agreement with the experimental measurements is observed.

Descriptors :   *ATOMS, *MOLECULES, *POTENTIAL THEORY, *ATOMIC PROPERTIES, *COLLISION BROADENING, FREQUENCY BANDS, PRESSURE, MOLECULAR STATES, TRANSITIONS, COMPUTATIONS, LINEAR SYSTEMS, INTERACTIONS, NITROGEN, OZONE.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Inorganic Chemistry
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE