Semi-Direct Band Models for the Transmittance Calculation

Abstract

A simple method has been developed to incorporate the wing contributions made by distant lines lying outside the interval concerned into the random band model for the transmittance calculation. Solutions have been obtained for four types of intensity-distribution function. The functional form of the transmittance obtained in this work for each intensity-distribution function is much simpler than that obtained by Wyatt et al. (1962) for the quasi-random band model.It has also been shown that the usual version of the quasi-random band model can be improved by using the same technique. Improvements are achieved in accuracy and, especially, in computation time.One of the models developed here has been applied to the transmittance calculations on the H2O rotational band. The results are in excellent agreement with the “exact”lineby-line calculation.