Ab initio and B3LYP–DFT calculations of GaP − and GaP 2−: the electron affinities and vibrational frequencies of GaP and GaP 2

Abstract

CCSD(T) and B3LYP equilibrium geometries, harmonic vibrational frequencies and electron detachment energies are reported for GaP − and GaP 2 −. GaP − has a 2 Σ + ground state with a 2 Π state 2.30 kcal/mol above, while GaP has a 3 Σ − ground state and a 3 Π state at 2.10 kcal/mol. The calculated adiabatic electron affinity (AEA) of GaP is 1.94 eV. GaP 2 − has a 1 A 1 ground state. The B3LYP and CCSD(T) AEA of GaP 2( 2 B 2 ) are 1.73 and 1.80 eV, respectively. The calculated spacings between the low-lying states and vibrational frequencies of GaP 2 − and GaP 2 are compared with recent experimental anion photoelectron data.