Hot Band Rotational Relaxation Time in Carbonyl Sulfide by Transient Infrared-Microwave Double Resonance
Rotational relaxation time (T) has been measured for pure Carbonyl Sulfide (('16)O('12)C('32)S) in a highly vibrationally and rotationally excited state (03('1f)0, J=24). A CO(,2) laser (P(,9)(24) line) was used to pulse excite the OCS gas: (01('1f)0, J=25) (--->) (03('1f)0, J=24). The resulting transient population difference between l doublet states, (03('1f)0, J=24) and 03('1e)0, J=24), was monitored with a microwave (7.4 GHz) probe signal. Individual transient infrared-microwave signals were analyzed and from the gain pulse shape it is concluded that population decay time (T(,1)) and polarization decay time (T(,2)) are approximately equal to a composite relaxation time (T). From the pressure dependence of T as pressure (p) changes from 0.04 to 0.3 Torr(5 to 40 Pa), it is concluded that (pT) = 32 ns(.)Torr = 4.3 (mu)s(.)Pa.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign