Raman spectra of fluid N₂

Abstract

The depolarized rotovibrational band in fluid N₂ has been measured in a wide temperature and density range. The behaviour of normalized second moment versus temperature and density is analysed in order to clarify the role played by the various non-rotational contributions. Practically no dependence on temperature is found while a net increase with density is present. Induced effects are carefully analysed in the dipole-induced-dipole approximation. In particular exact formulas are derived for both the intensity and second moment of induced cross contributions. Good agreement with experimental data is obtained. The cross contributions are responsible for the observed second moment increase with density.

The different second moment density behaviour of rotovibrational and rotational bands has been interpreted in terms of the different permanent anisotropies and different many-body contributions involved in the scattering process.

Notes

Work supported by GNSM (CNR) and MPI.