Ghahramani, Edwin2023-06-072023-06-071984https://unbscholar.lib.unb.ca/handle/1882/30099The 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.vii, 74 pagesprinten-CAhttp://purl.org/coar/access_right/c_16ecsenior reportLees, RonPhysics