VT relaxation in N2and CO

Using a vibrational pumping technique based on transient stimulated Raman scattering we have measured values for VT relaxation of the levels in N2and CO at room temperature and in the presence of several deactivants; the N2data represent the only room temperature data presently available. A mode-locked ruby laser, delivering picosecond pulses, vibrationally pumps the molecule by TSRS; the subsequent decay of the vibrational population is followed by light scattering off localized refractive index changes caused by heating arising from the thermalization of the excited state population. For rapidly relaxing molecules, heat conduction is negligible and the scattered light signal behaves as Since CO and N2relax quite slowly, heat losses can be appreciable; the resulting behavior of the scattered light signal and its relationship to a τVTwill be discussed. Thus far values of 6 ± 3 and 0.7 ± 0.35 s-atm have obtained for N2and CO, respectively. In addition, data for CO deactivation by CO chemical laser contaminants, such as COS, SO2, and CS2, and preliminary temperature dependence measurements will be discussed.