The ground and low-lying excited states of Ga2S3-, Ga2S3, Ga3S2- and Ga3S2 are studied using B3LYP, MP2 and CCSD(T) methods with flexible one-particle basis sets. Neutral Ga2S3 and Ga3S2 have similar C-2v 'V' gas phase equilibrium geometry. On the other hand, Ga2S3- adopts the C-2v kite geometry while Ga3S2- prefers the three dimensional geometry (D-3h symmetry). Electron detachment energies from the ground electronic states of the anions to several neutral states are presented and discussed. The predicted adiabatic electron affinities of Ga2S3 and Ga3S2 are 3.30 eV and 2.76 eV at the CCSD(T)//B3LYP level and 6-311+G( 2df) as the basis set. (C) 2008 Elsevier B.V. All rights reserved.