Geometries and electronic structures of Ga sub(2)Se sub(3), Ga sub(3)Se sub(2) and their anions. Theoretical insights

We hereby report a theoretical study on the equilibrium geometries, electronic structures and harmonic vibrational frequencies of Ga sub(2)Se sub(3), Ga sub(3)Se sub(2) and their anions. The ground and low-lying excited states of Ga sub(2)Se sub(3) super(-), Ga sub(2)Se sub(3), Ga sub(3)Se sub(2) super(-) and Ga sub(3)Se sub(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 sub(2)Se sub(2) super(-) adopts the C sub(2)vkite geometry while Ga sub(2)Se sub(3) has a 'V' geometry. Ga sub(3)Se sub(2) super(-) has a three-dimensional 'D sub(3)h geometry and Ga sub(3)Se sub(2) prefers the three-dimensional 'C sub(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 sub(2)Se sub(3) is calculated to be 3.23 eV when using the 6-311+G(2df) basis set and that of Ga sub(3)Se sub(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.