Secondary ion mass spectra of some simple organic molecules

Abstract

A systematic study of the mass spectra obtained by ion bombardment of the pentane isomers, a series of simple ketones and an ester is described. The spectra obtained are clearly structure sensitive. The form of the spectrum is dependent on the primary ion energy. The lower the primary ion energy the greater the fragmentation of the molecule.

Simple molecular fragmentation appears to be the main mechanism for ion formation although solid state effects are important. It is evident that the fragments emitted as ions originate from nearest neighbour atoms in the solid compound. Furthermore, there is no real evidence for molecular rearrangement before or after emission. The potential of the technique for obtaining mass spectra from non-volatile compounds is thus demonstrated.