COLLISION-INDUCED MICROWAVE DOUBLE RESONANCE SPECTRUM OF OCS IN THE $v_{2}=1$ STATE.

Author Institution: Department of Physics, University of New BrunswickCollision-induced transitions have been studied by microwave double resonance for the $(3\leftarrow 2)_{p} - (2\leftarrow 1)_{S}$ rotational level system of OCS in the first excited bending state, $V_{2} = 1$, with the individual M-substates resolved by a Stark field. The $\ell$-doubling of the levels leads to a rather complex spectrum with several novel and interesting features. The implications of these will be discussed in terms of collisional selection rules on J, M and parity. A notable feature is the observation of $\Delta M = 2$ collisional transitions, which are forbidden under first-order dipolar selection rules. This indicates that higher-order collisional processes are important, as found previously for ground state OCS