Calculation and Simulation of Absorption Line Broadening in Water Vapor by Noble Gas Atoms

Abstract

Semiclassical methods have been applied to calculate the collisional broadening of water vapor absorption lines by noble gas atoms (Ar, He, Ne, and Kr). An analytical model has been proposed for line half-widths. The model parameters have been determined for the ν2 band of the H2O molecule for all the buffer gases under consideration, as well as for the bands 3ν1 + ν3 and 2ν1 + 2ν2 + ν3 in the case of the broadening by argon. In the latter case, the model parameters that determine the temperature dependence of the half-widths of the water vapor lines of the ν2 band have been found. The model proposed describes well the known experimental data and permits a relatively simple calculation of the H2O line half-widths for the bands and the buffer gases under consideration in a wide range of rotational quantum numbers. For the ν2 band, the model calculations in the case of the broadening by argon can be performed up to temperatures of 2500 K.