Pressure dependence of rotational relaxation times T1 and T2 in the J=0−1 transition of OCS

Time-domain experiments on the OCS J=0−1 ΔM=0 microwave transition have been used to measure the pressure dependence of two relaxation times: for radiation from a coherently excited sample, 1/T2=37.66±0.10 μsec−1⋅Torr−1, and for the population difference between the J=0, M=0, and J=1, M=0, states, 1/T1=38.10±0.18 μsec−1⋅Torr−1. These results imply that not all collisions induce dipole-allowed transitions. These values are consistent with previous linewidth values, beam maser experiments, and four-level double resonance experiments.