Ionization potential and electron affinity of the Au atom and the AuH molecule by all-electron relativistic configuration interaction and propagator techniques

Abstract

We present the results of all-electron relativistic and nonrelativistic ab initio calculations on ionization potentials, electron affinities, and excitation energies for the gold atom and the gold hydride molecule. Values obtained from selecting multireference configuration interaction (CI) methods, full-class singles–doubles multireference CI, averaged coupled pair functional (ACPF), and various Green’s function methods {outer valence Green’s function (OVGF), algebraic diagrammatic construction in third order [ADC(3)]} are compared and generally found to be in good agreement. Relativistic effects are taken into account by means of the spin-free no-pair Hamiltonian obtained from a second-order Douglas–Kroll transformation. The influence of relativistic effects and electron correlation on the investigated properties is discussed. As far as experiments are available, our calculations are in good agreement with the measurements. Our best estimate for the ionization potential of the gold atom is 9.08 eV (experiment 9.22 eV) and 2.28 eV for the electron affinity (experiment 2.31 eV).