Photochemistry of Dimethyl Cadmium on Quartz and Silicon Surfaces

摘要

The photochemistry of adsorbed dimethyl cadmium at submonolayer levels on a fusedquartz and a Si(111) single crystal surface has been investigated at 193 and 248 nm using a rare-gas fluoride excimer laser. The desorbed gaseous products, which include CH2, CH3, CH4, C2H4, C2H5, C2H6, Cd, CH3Cd and (CH3)2Cd, have been detected by time-of-flight mass spectrometry by means of either electron impact or resonance-enhanced multiphoton ionization. The translational energies of these desorption products could be characterized in terms of Maxwell-Boltzmann temperatures, TMB's, which depend strongly on sample dosage (surface coverage), laser fluence, photon energy and the nature of the substrates employed. The TMB's