Abstract

Resonant two-photon ionization spectroscopy of diatomic metals and semiconductors is now helping us to understand the electronic structure of these interesting species in some detail. Recent results on GaAs (demonstrating an X³Σ⁻ ground state and a ³Π state located near 23,500 cm⁻¹, which is predissociated by a repulsive ⁵Σ⁻ state), NiCu (demonstrating electronic structure which may be understood in terms of ligand field theory), and NiPd, NiPt, PdPt, and Pt₂ are presented. In Ni₂, NiPt, and Pt₂, abrupt onset of predissociation in a very dense manifold of electronic states allows the bond strengths to be measured as 2.07, 2.80, and 3.14 eV, respectively. Compared to the coinage metal dimers CU₂, CuAu, and AU₂, with bond strengths of 2.01, 2.34, and 2.29 eV, respectively, these results indicate d-electron contributions to the bonding of 0.06, 0.46, and 0.85 eV in Ni₂, NiPt, and Pt₂, respectively. High resolution investigations of NiPd and NiPt are also presented.

© 1989 Optical Society of America