Constant Acceleration Approximation in Collision-Induced Absorption

Abstract

In terms of the constant acceleration approximation, introduced by Oppenheim and Bloom in 1961, the line shapes occurring in collision‐induced absorption have a simple form that is suitable for numerical calculation. To test the reliability of the constant acceleration approximation in describing the appropriate time dependent distribution function, we compare a particular line shape in this approximation with the direct computer calculation of McQuarrie and Bernstein. A similar comparison with the experimental results of Bosomworth and Gush is also made. From both comparisons it follows that the constant acceleration approximation, as applied to a short range intermolecular interaction, is poor at all frequencies.