Geometries and electronic structures of Ga2Se3, Ga3Se2 and their anions. Theoretical insights

Abstract

We hereby report a theoretical study on the equilibrium geometries, electronic structures and harmonic vibrational frequencies of Ga 2 Se 3 , Ga 3 Se 2 and their anions. The ground and low-lying excited states of Ga 2 Se, Ga 2 Se 3 , Ga 3 Se and Ga 3 Se 2 are studied at the B3LYP and/or MP2 and CCSD(T) levels in conjunction with 6-311+G(d) and 6-311+G(2df) one particle basis sets. Ga 2 Se adopts the C 2 v kite geometry while Ga 2 Se 3 has a ‘V’ geometry. Ga 3 Se has a three-dimensional ‘D 3 h ’ geometry and Ga 3 Se 2 prefers the three-dimensional ‘C 2 v ’ structure. Electron detachment energies from the ground electronic states of the anions to several neutral states are reported and discussed. At CCSD(T)//MP2 level, the adiabatic electron affinity (AEA) of Ga 2 Se 3 is calculated to be 3.23 eV when using the 6-311+G(2df) basis set and that of Ga 3 Se 2 is 2.77 eV with the 6-311+G(d) basis set. The findings of this research are analyzed and compared with gallium oxide and sulfide analogues.