COLLISIONAL DEACTIVATION OF VIBRATIONALLY HIGHLY EXCITED BENZYL RADICALS

The collisional deactivation of vibrationally highly excited benzyl ra dicals in the ground electronic state has been investigated. Vibration ally excited benzyl radicals have been generated using the fast dissoc iation of vibrationally excited ethylbenzene prepared from UV absorpti on followed by fast internal conversion. Subsequent to complete collis ional deactivation the benzyl radicals have been reexcited by the abso rption of a further UV-photon also followed by fast internal conversio n. Once again the collisional deactivation of the benzyl radicals has been monitored by rime-resolved UV absorption spectroscopy. Average en ergies transferred per collision have been determined by comparison of absorption-time profiles with different initial vibrational energies. it was found that the rare of collisional deactivation of the open sh ell benzyl radical is almost identical to the rare of collisional deac tivation of the closed shell hydrocarbons of similar size.