The potential energy surfaces of Ga2O3- and Ga3O2- are studied at the B3LYP, MP2 and CCSD(T) levels using flexible one-particle basis sets. Ground electronic states of both anions have the C-2v kite geometry. Neutral Ga2O3 and Ga3O2 have the C-2v Y geometry. Electron detachment processes from the anions' ground states to several neutral states are presented and discussed. At the CCSD(T)/6-311+G(2df)//B3LYP/6-311+G(2df) level, the adiabatic electron affinities (AEA) of Ga2O3 and Ga3O2 are computed to be 3.19 and 2.23 eV, respectively. (c) 2005 Elsevier B.V. All rights reserved.