The binding energies of small Ar, CO and N-2 cluster ions

This article reviews the available information on the thermochemistry of argon, carbon monoxide and nitrogen cluster ions with focus on kinetic energy release (KER) studies of the dissociative ionization of neutral clusters performed in the authors laboratory. The latter constitutes a variant of translational energy spectroscopy (TES). The information derived includes the adiabatic ionization energies and the binding energy of small cluster ions. Here we present experimental data together with extensive theoretical calculations of the KER based on ab initio structure data. The theories employed range from simple empirical formula which allow a quick estimate of the KER to extensive phase space theory calculations. The binding energies of the ions are: D-0(Ar-2(+)) = 1.29eV, D-0(ArN2+) = 1.19 eV, D-0(ArCO+) = 1.00eV, and D-0((N-2)(2)(+)) = 1.06 eV. The binding energy of the C2O2+ is D-0(C2O2+) = 1.80 eV, significantly larger than many previous values. The latter represents in fact a molecular ion. (C) 2002 Elsevier Science B.V. All rights reserved.