VIBRATIONAL/TRANSLATIONAL RELAXATION RATE MEASUREMENTS BY THE PHOTOACOUSTIC PHASE SHIFT METHOD
Loading...
Date
1982
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The photoacoustic and infrared fluorescence signal following $CO_{2}$ laser excitation was measured for $CO_{2}, N_{2}O$, and $SF_{6}$. The amplitude and phase of the resulting signal was measured as a function of modulation frequency and the V=V and V=T relaxation rates were determined by least squares fitting. The branching ratio for collisional deexcitation from (0,0,1) to the (0,m,0) states is determined for $N_{2}O$ and $CO_{2}$. The effect of thermal diffusion on the photoacoustic signal is observed at low pressure and included in the data analysis. Radiation trapping of the infrared fluorescence signal is also observed.