N2-, O2-, and air-broadened half-widths, their temperature dependence, and line shifts for the rotation band of H216O

Complex Robert-Bonamy (CRB) calculations of the half-width, its temperature dependence, and the line shift have been made for the rotation band transitions of H216O for N2 or O2, as the bath molecule. First the atom-atom component of the intermolecular potential was adjusted to reproduce the half-widths of the 22 and 183 GHz transition determined by Payne et al. (IEEE Trans. Geosci. Remote Sensing 46 (2007) 3601-3617). Then the line shape parameters were determined at seven temperatures (200, 225, 275, 296, 350, 500, and 700 K) for the H2O-N2 and H2O-O2 systems. The air-broadened values were determined at each temperature by the standard method. The half-widths, their temperature dependence, and the line shifts were studied as a function of the rotational quantum numbers. Estimating line shape parameters by scaling from one perturbing gas to another was investigated. The calculations were compared with measurement.