Knowledge Bank

Widths and shifts of water-vapor lines perturbed by nitrogen and oxygen are calculated using a complex-valued implementation of Robert-Bonamy (RB) theory developed at UMLowell. The static intermolecular potential is described as a sum of electrostatic forces and Lennard-Jones (6-12) atom-atom terms and the vibrational dependence of the isotropic potential is obtained from the polarizability of $H2O$ assuming a dispersion interaction. Literature values have been used for all physical parameters. The calculations are compared with experiment. Effects of the fully complex formulation, the order of the atom-atom expansion, energy gap, etc, on the final calculated halfwidths and line shifts are discussed.