Table of Contents
Laser Chemistry
Volume 10, Issue 3, Pages 159-167
http://dx.doi.org/10.1155/1990/39014

Dynamics of Vibrational Relaxation of Multiphoton Excited SF6 Molecules in Gaseous Mixtures Containing Ozone and Inert Gases (He, Ar, Kr)

Chair of Physical Chemistry, Chemical Department, M.V. Lomonosov State University, Lenin Hills, Moscow V-234, Russia

Received 9 November 1988; Accepted 16 January 1989

Copyright © 1990 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

SF6 at pressure of 0.6 Torr in gas mixtures with ozone (0 ÷ 5 Torr) and inert gases: He, Ar, Kr (0 ÷ 5 Torr) was vibrationally excited with and IR pulsed radiation of CO2 TEA laser at 10P20 laser line (F= 0.6 J/cm2). The vibrational energy transfer from multiphoton excited (MPE) molecules SF6 to the components of gaseous mixture was probed by UV absorption of ozone at λ = 253.6 nm band. The relaxation process of MPE molecules SF6 was proposed to occur through parallel V-V' and V-T collisional channels. Based on the kinetic model, collisional rate constants were determined from the time evolution of UV absorption data after laser shot. The obtained values of relaxation rate constants are: KVVSF6O3=7.7,1013cm3/s,KV-TSF6He=3.11013cm3/s,KVTSF6Ar=2.31013cm3/s,KVTSF6Kr=7.71014cm3/s,KVTSF6SF6=(4.8÷6.4)1013cm3/s.

The observed decay of IR fluorescence from MPE SF6 molecules at λ=6.3μm wave number in SF6-Kr gas mixtures had an exponential time profile with the constant characteristic relaxation time (V-T). The rate of IR fluorescence cluenching allowed us to find an effective V-T relaxation rate constants for collisional partners: KV-TSF6Ar=7.81014cm3/s. KT-VSF6SF6=1.01012cm3/s.