Abstract
Using the technique of the semi-direct random model recently developed by this author, the functional form of the average transmittance has been derived for the absorption band in which lines obey to the exponential-tailed S-1 intensity distribution. The accuracies of this model and the other semi-direct random models previously developed by this author have been examined by calculating the transmission functions of H2O rotation band and CO2 15μ band. It has been shown that the accuracies depend on the vaule of the interval, to which the average transmittances are calculated. The highest accuracy is chieved by the semi-direct quasi-rondom model with relatively small values of the interval. The semi-direct random models, especially for the exponential intensity distribution, can also give good accuracies in view of the present uncertainty in the theoretical values of the line intensities or line half-widths.
