Double Resonance Studies of Collision-Induced Transitions in a Molecular Beam

Abstract

Various types of collision—induced transitions occur among molecular levels. Relevant molecular energy levels and transitions among them are schematically shown in Fig.l and 2. The α- and β-transitions, named by Oka on his microwave-microwave double resonance experiments [1], are the collision-induced transitions between rotational levels and inversion doubling levels, respectively. Transitions between vibrational levels mostly occur as a V-V energy transfer, because an energy discrepancy at the collision is too large to be absorbed by a translational degree of freedom [2]. Since the rotational state has a dual parity in a case of symmetric top molecule, direct transitions between closely spaced M-sublevels occur.