ADSORPTION AND DISSOCIATION OF METHANOL ON ALUMINUM(100) - THEORETICAL-ANALYSIS OF REACTION-MECHANISM

The adsorption of methanol on aluminum (100) surface is modeled by qua ntum mechanical calculations on a small cluster, using hybrid Hartree- Fock/density functional theory. The enthalpy of adsorption at low cove rage is calculated for the high-symmetry sites. The relevance of tippi ng of the prevalent methoxy species before C-O bond scission is examin ed. A new mechanism for dissociation is proposed, which is in excellen t agreement with experimental determinations of the energy of activati on for dissociation. Principles of transition-state theory are correla ted to theoretical calculation of vibrational frequencies. Current ass umptions from molecular orbital theory, as applied to surface reaction energetics, are called into question.