Photoionization Spectroscopy of KAu and NaAu Diatomics

Abstract

The new metal diatomics KAu and NaAu are studied using resonant two-photon ionization (R2PI) electronic spectroscopy. These species are produced by laser vaporization of a “salted” gold rod in a pulsed nozzle cluster source. Analysis of the spectra provides the vibrational constants for the excited states and correlations to specific atomic asymptotes. Energetic cycles provide determinations of the ground-state dissociation energies. The values are D0‘ ‘ = 2.75 ± 0.2 eV for KAu and D0‘ ‘ = 2.64 ± 0.2 eV for NaAu. These dissociation energies for the heteronuclear diatomics are significantly greater than those for the corresponding homonuclear diatomics Na2, K2, or Au2. Partial ionic character in the ground state bonding is implicated, analogous to that observed previously for silver and copper-alkali diatomics.