Use of a chemical laser for molecular-beam scattering experiments

We describe the characteristics of a cw HF chemical laser used for molecular-beam scattering studies. Unlike with most such lasers, a complete population inversion is achieved, resulting in ∼100 mW of single-line output even for some R-branch transitions. The laser emission shows a prominent Lamb dip and can achieve high spectral resolution (≲15 MHz). For inelastic scattering studies, improved signal stability and intensity has been attained by lowering the resolution, thereby better matching the laser emission and molecular-beam absorption linewidths. Preliminary measurements of rotationally inelastic differential cross sections for HF scattered into J′ = 1, 2, 3 by Ar are also presented.