The adsorption of methanol on the (110) surface of g -alumina was investigated using both ab initio and density functional theory quantum chemical methods. A [Al 3 O 9 H 10 ] ϩ cluster model comprising one tetrahedral and two octahedral aluminum cations were used to describe the surface and the mechanism of adsorption of methanol. This has allowed us to rationalize the stable structures of adsorbate and the mode of bonding. The IR frequency shifts between the gas phase and the adsorbed species were also calculated and they exhibit good agreement with experiment. ᭧