Dissociation dynamics of positive-ion and negative-ion fragments of gaseous and condensed Si(CH3)(2)Cl-2 via Si 2p, Cl 2p, and Cl 1s core-level excitations

摘要

The state-selective positive-ion and negative-ion dissociation pathways of gaseous and condensed Si(CH3)(2)Cl-2 following Cl 2p, Cl 1s, and Si 2p core-level excitations have been characterized. The excitations to a specific antibonding state (15a(1)(*) state) of gaseous Si(CH3)(2)Cl-2 at the Cl 2p, Cl 1s, and Si 2p edges produce significant enhancement of fragment ions. This ion enhancement at specific core-excited states correlates closely with the ion kinetic energy distribution. The results deduced from ion kinetic energy distribution are consistent with results of quantum-chemical calculations on Si(CH3)(2)Cl-2 using the ADF package. The Cl- desorption yields for Si(CH3)(2)Cl-2/Si(100) at similar to 90 K are notably enhanced at the 15a(1)(*) resonance at both Cl 2p and Si 2p edges. The resonant enhancement of Cl- yield occurs through the formation of highly excited states of the adsorbed molecules. These results provide insight into the state-selective ionic fragmentation of molecules via core-level excitation. (c) 2006 American Institute of Physics.