Optoacoustic measurements of energy absorption in CO_2 TEA-laser-excited SF_6 at 293 and 145 K

The optoacoustic technique is used to measure the absorption of CO2 TEA laser energy in SF6 as a function of frequency and energy flux at 293 and 145 K. The behavior of absorbed-energy versus incident-energy flux curves shows a strong dependence on frequency at 145 K, whereas at 293 K the dependence is less pronounced. When the CO2 pulse is lengthened sufficiently, laser-induced hot-band effects arising from vibrational relaxation during the pump pulse can be observed.