Density-Dependent Isotropic Raman Line Shapes in Compressed Room-Temperature Nitrogen

Abstract

Using the model developed previously by Everitt and Skinner [J. Chem. Phys. 2001, 115, 8531], we calculate Raman line shapes of nitrogen at room temperature, from the dilute gas limit to over four times the critical density. At low density, it is necessary to use the full Kubo line shape formula, rather than its motionally narrowed limit. Our results for the average frequency shift from the gas phase, the peak frequency shift, and the line width are all in excellent agreement with experiment over the entire density range. The calculations shed some light on the competing physical mechanisms that are responsible for the interesting nonmonotonic density dependences of both the shift and width.