Half-widths of H216O, H218O, H217O, HD16O, and D216O:: I.: Comparison between isotopomers

Pressure-broadened half-widths are determined using the complex Robert-Bonamy (CRB) formalism for five isotopomers of water vapor. The calculations are made with nitrogen and oxygen as the perturbing gases. The intermolecular potential is taken as a sum of electrostatic contributions, Lennard-Jones (6-12) atom-atom, and isotropic induction and dispersion components. Calculations made using recently determined Lennard-Jones (L-J) parameters for deuterium are compared with previous calculations that utilized only the hydrogen L-J parameters. The dynamics of the collision process are correct to second order in time. Ratios of the half-width of the principal isotopomer to the other isotopomers are determined and discussed with particular emphasis on predicting half-widths of the lesser isotopic species from the values for the principal species. (C) 2003 Elsevier Science Ltd. All rights reserved.