Electronic and geometric structure of the diatomics ScN, ScP and ScAs

Abstract

The ground and low-lying excited states of ScN, ScP and ScAs have been studied at the MCSCF and MCSCF + 1 + 2 level. They all have a triply bonded 1Σ + ground state and several low-lying boubly bonded states of 3Σ +, 1Π and 3Π symmetry. The calculated bond energies (relative to the ground state atoms) and bond lengths of the 1Σ + states are ScN (2.72 eV, 1.768 Å) ScP (1.54 eV, 2.277 Å) and ScAs (1.36 eV, 2.389 Å). Our calculated bond length for ScN is in reasonable agreement with the experimental result (1.695 Å) of Ram and Bernath. The 3Σ + state which has two π bonds and no σ bond is 0.33 eV above the 1Σ + in ScN and 0.80 and 0.87 eV in ScP and ScAs.