Vibrational-translational relaxation time spectroscopy of polyatomic molecules

We report experimental studies of the frequency dependence of the vibrational-translational relaxation time of polyatomic molecules strongly excited by resonant laser radiation. In particular, we have examined the behavior of SF6 and CF2Cl2, two molecules of great practical and theoretical interest. Our analysis has highlighted a strong dependence of the relaxation time on the exciting laser wavelength. The laser ‘spectra’ of the relaxation times are very similar to the optical absorption spectra for both molecules, thus suggesting the possibility of using the study of the relaxation times to obtain useful spectroscopic information of polyatomic molecules.