Measurement of the rate of excitation and deactivation of OCS(001), N2O(001), CS2(001), and C2N2(00100) using laser excited CO as a pumping source

Abstract

The laser fluorescence method has been used to measure CO( v = I) collisional transfer rates in several binary and ternary gas mixtures at 296 oK. Excitation of the CO(v = 1) level was achieved using pulsed 4.6 porn radiation from a frequency doubled CO, laser. The relative inertness of CO molecules towards V ~ T deactivation greatly facilitates the study of vibrational relaxation rates of the additive species in selected cases. In this paper, intermolecular V ~ V transfer rates at 296°K are reported for CO(v = I) with N,O, OCS, SO" CS,' C,N" and for CO(v =2) with CO. In addition, the additive deactivation rates were determined for the following collisional processes: N ,0(00 I) with N,O, CO, Ar; OCS(OOI) with OCS, CO, Ar; CS,(OOI) with CS" CO; and C,N,(OOIOO) with C,N, and CO.Precautions taken to assure high gas purity have been reported previously. I All condensable gases were freeze-pumped and outgassed at 77 OK. The gases CzN z , CS z , and OCS were further purified by trap-to-trap distillation. The middle fractions were withdrawn for sample use. Carbon monoxide and Ar were stored under liquid N z several hours prior to sample preparation.

Collisional Deactivation of CO2(0001) and N2O(0001) by Toluene Isotopomers: Near-Resonant Energy Transfer from N2O(0001)

“…They make an important comparative pair because they are isoelectronic, have the same mass, and have similar vibrational frequencies. CO 2 has long been used in this role (see, for example, refs −12), but the studies of N 2 O began much more recently and are far less extensive. − Most experimental measurements have been confined to deactivation of both CO 2 and N 2 O excited to the (00 0 1) vibrational level of the asymmetric stretch mode, ν 3 .…”