Synchrotron radiation inner-shell photoionization of atomic and molecular gases

Abstract

A time-of-flight (TOF) spectrometer has been used to measure the average kinetic energies of near-thermal atomic and molecular ions, as well as energetic molecular ion fragments, produced by inner-shell photoionization of atomic and molecular gas targets using X-rays from the National Synchrotron Light Source (NSLS). While atomic and molecular ions acquire very little energy from the initial photoionization event and subsequent vacancy cascades, multiply-charged molecular ions decompose rapidly, producing fragment ions which have kinetic energies determined by their configuration at the moment of decomposition. The strong effects observed suggest that this technique may be extended to the study of configurations of free molecules as well as the orientation of molecules adsorbed on surfaces.