UV spectroscopy of molecular “hot” bands

Abstract

We consider both the theory and the experimental measurement of the temperature and frequency dependences of absorption cross sections of molecular “hot” bands. In order to calculate the molecular UV spectra, a generating function method applicable to molecules with an arbitrary vibrational distribution (VD) was used. In this approach the Gaussian (central) part of the spectrum was found to be insensitive to the shape of VD, depending on the average molecular vibrational excitation energy and the spectroscopic parameters. In contrast, the long-wavelength wings depend on peculiarities of the VD shape. Thus spectroscopic measurements directly probe the molecular distribution of highly excited vibrational states.