Electron detachment energies of Al4P− and Ga4P−

Geometric and electronic structures of Al4P−, Al4P, Ga4P− and Ga4P are studied using B3LYP-DFT and CCSD(T) methods with the 6-311+G(2d) and 6-311+G(2df) one-particle basis sets. The anions have similar square pyramidal (C4v) gas phase equilibrium geometry while the neutral species possess the trapezium (C2v) planar geometry in accordance with the predictions of Boldyrev and Wang [A.I. Boldyrev, L.S. Wang, J. Phys. Chem. A 105 (2001) 10759]. Electron detachment processes from the ground electronic states of the anions are presented and an attempt is made to assign the features observed in the anion photoelectron spectra of Al4P− and Ga4P−.