Photon Counting Detector System Research Articles

Pure-Rotational Raman Scattering in a CO_2 Electric Discharge

We wish to report the observation of pure-rotational Raman scattering in a low-pressure CO2 electric discharge. The results were obtained by use of an argon-ion laser and a sensitive photon-counting detection system. The spectrum clearly shows pure-rotational Raman scattering originating in the 0110 vibrational state of CO2 superimposed on the ground-state pure-rotational Raman spectrum. In unexcited CO2 gas at a pressure of 40 torr, the pure-rotational scattering in the 0110 state has been observed photoelectrically. In addition, high-resolution photographic studies of this effect were carried out using an He-Ne laser and a sample pressure of 1 atm. The rotational constants deduced from this study are B0000= 0.39027±0.000007 cm-1, D0000 = (12.9±0.3)×10-8 cm-1, B0110c = 0.39065±0.00004 cm-1, and D0110c= (8.2±4)×10-8 cm-1. These values are in good agreement with previous infrared measurements.