ROTATIONAL QUANTUM CHANGES ACCOMPANYING VIBRATIONAL-RELAXATION IN THE 1AU STATE OF GLYOXAL

Changes of the rotational quantum state occurring simultaneously (in one single collision step) with the deactivation of the torsional vibration ν7 have been measured in glyoxal 1Au. Selective excitation of rotational levels in the vibronic level 71 was accomplished by means of a tunable dye laser. A near thermal distribution of rotational levels in the O0 state was attained as the result of a single collision. Intramolecular vibration-to-rotation transfer was not found. Similarly, a nearly thermalized distribution of rotational levels in the O0 state has been observed as the result of one single collision after selective excitation of a restricted number of rotational levels in the vibronic 81 state in the presence of different collision partners. © 1979.