Mechanism of fragmentation of organic molecules during keV particle bombardment

Abstract

A simplified scheme is presented to distinguish between surface and gas-phase fragmentation of molecular ions in SIMS or FABMS experiments. The scheme is based on the measurement of the polar angle distribution of ejected parent and daughter cluster-ions and is derived from straightforward considerations of classical mechanics. Examples are given for chlorobenzene, benzene and pyridine adsorbed onto Ag(111) at 153 K.