Source flow effect on line shape.

The combined effect of mean and thermal particle motion on Doppler line shape is evaluated. Optical radiation transverse to the axis of a source flow with semi-angle theta(e) is considered in the limit theta(2)(e) <<1. Expressions for gain and anomalous index of refraction are deduced in terms of radiation frequency and a parameter X(e) which characterizes the ratio of mean to thermal motion in the optical path direction. The decrement in cw chemical laser output power, due to transverse flow expansion, is briefly noted.