Microwave double resonance study of collision induced population transfer of rotational energy in OCS

Abstract

The technique of microwave double resonance was applied to investigate collision induced transitions between rotational levels of OCS in the ground vibrational state, with the M sublevels separated by a Stark field. The (1+2)p-(2+3)s' (1+2)p-(3+4)s and (2+3)p-(1+2)s systems have been studied for pure OCS and its mixture with excess He. For four level systems having dipolar connections (AJ = 1; LlM = 0, ±1; parity ±++) be.tween pump and signal levels, it is found for OCS that the dipole-type• AJ = 1 transitions always dominate the collisional transfer, but for the OCS-He mixture that AJ = 2 quadrupole-type transitions are dominant. The fractional intensity changes AI/I for almost all the four level transitions were in good agreement with the theoretical results.