THE 193-NM FRAGMENTATION AND IONIZATION OF TRIMETHYLALUMINUM - EVIDENCE FOR PHOTOINDUCED ALPHA-HYDROGEN ELIMINATION

Results are reported on the 193 nm excitation of trimethylaluminum under collisionless conditions. Time-of-flight mass spectra are monitored at several different excimer laser powers. At relatively low powers, the mass spectra consist solely of masses 27 and 57, presumably the Al+ and Al(CH 3)+2 ions. At higher laser powers, however, mass 58 is readily observed, suggesting the presence of a reaction channel involving α-hydrogen elimination to form the AlH(CH3) 2 photofragment. This observation is interpreted in the context of recent theoretical calculations by Higashi and Steigerwald [Appl. Phys. Lett. 54, 81 (1989)].