PHOTOLYSIS OF PHENYLSILANE AT 193 NM - ENERGY-DISTRIBUTIONS OF THE FRAGMENTS

The energy distributions of the fragments formed in the 193-nm photolysis of phenylsilane were measured. The vibrationally excited SiH2 X(0upsilon20) (upsilon2 = 0-4) radicals were detected by means of the laser-induced fluorescence method. Although the vibrational population is partly inverted just after the photolysis, the amount of energy distributed to the SiH2 vibration is a relatively small portion of the total excess energy. The 248-nm photoexcitation of phenylsilane to the S1 state also produces SiH2. These observations suggest that SiH2 is formed from highly vibrationally excited S0 state of phenylsilane, which is produced via internal conversion. The emission from silicon atoms and SiH radicals was also detected. The rotational and vibrational distributions of SiH(A2DELTA) were estimated on the basis of emission spectrum. The photolysis laser power dependence of these emissions indicates that SiH and Si are produced by a multiphoton process.