Neutral, cationic, and anionic AlOH, HAlO, GaOH, and HGaO species were studied using QCISD method with the aug-cc-pVTZ+5s4p3d basis sets. The kinetic barriers for the isomerization processes leading from MOH to HMO (M = Al, Ga) were also estimated for the neutral and ionic systems. It was found that AlOH and GaOH neutral molecules correspond to the global minima while their isomers are higher in energy by ca. 1.8-1.9 eV. The most stable neutral isomers (AlOH and GaOH) do not form stable anionic states while their tautomers (HAlO and HGaO) bind an excess electron forming stable valence (ground) and dipole-bound (excited) states of anions. (C) 2009 Elsevier B. V. All rights reserved.