Density narrowing of a rotational line of H₂ dissolved in Ar

Abstract

The profile of the pure rotational S(1) line of H₂ dissolved in Ar has been investigated at T = 164 K, up to densities of the order of twice the critical one. From the experimental profiles we have obtained a characteristic half-width, which decreases with increasing density. To discuss the observed density narrowing of the S(1) line we propose a simple model to describe our low density data. We find that this model is in good agreement with the experimental results up to the critical density.