Fragmentation of sputtered vanadium and niobium cluster ions, kinetic release and dissociation energy
Abstract
The generation and unimolecular fragmentation of V + and Nb + clusters formed in sputtering vanadium and niobium surfaces by Xe+ ions has been studied. The method of measuring the kinetic energy of fragment ions (kinetic energy release distribution) has been used to determine the dissociation energy. Kinetic energy spectra have been measured in the field-free zone (corresponding to a time window of 10−5–10−4 sec after emission) of an ion microanalyzer with double focusing in reverse geometry. The results of spectra measurement were treated using the Rice-Ramsperge-Kassel theory of unimolecular reactions and the “evaporative ensemble”, which allowed us to calculate the dissociation energies of homonuclear V 1 (n= 5–11) and Nb 1 (n = 3–8) clusters.