On the formation mechanism of MCs2+ molecular ions under varying oxygen environment

Formation of MCs2+ molecular ions under Cs+ bombardment of silver surface has been investigated in the SIMS process under varying oxygen environments. Energy distributions of MCs+ and MCs2+ ions have shown a remarkable dependence on the changing oxygen environment. The changes in the intensities of the above molecular species are attributed to the changes in the resputtered Cs+ intensity due to the decrease in the local surface work function. The MCs+ molecular ion has been found to form via the recombination of a neutral M0 atom with a Cs+ ion and its formation probability remains unaffected by changing oxygen environment. A systematic study on the kinetic energy distributions of secondary Cs+, Cs2+, MCs+ and MCs2+ ions and the estimation of the mean emission energies of various constituents participating in the respective formation processes confirm that the MCs2+ molecular ion formation via recombination of a neutral MCs0 molecule with a Cs+ ion is the most probable one.