Fragmentation processes of vanadium and niobium oxide clusters sputtered by ion bombardment

The mass distribution of emitted V _n O _m ^? and Nb _n O _m ^? clusters and their unimolecular decay by all stoichiometrically possible fragmentation channels, which takes place under the sputtering of niobium and vanadium surfaces and blowing by oxygen, are studied. It is shown that the formation, excitation, and unimolecular fragmentation of V _n O _m ^? and Nb _n O _m ^? clusters can be described by a statistical recombination mechanism. Clusters are formed over the target surfaces as a result of binary collisions of independently sputtered ions, atoms, and molecules.