Adsorption of n methanol molecules on MgO(100) with n = 1 to 4: A theoretical study

A.H. RODRÍGUEZ, M.M. BRANDA AND N.J. CASTELLANI

JOURNAL OF PHYSICAL CHEMISTRY

American Chemical Society

Lugar: Washington; Año: 2007 vol. 111 p. 10603 - 10609

0022-3654

The adsorption of methanol n-mers with n ) 1-4 on the MgO(100) surface has been investigated by means of density functional theory (DFT) cluster model calculations. Two different configurations have been found for dimers, trimers, and tetramers. In both cases, a trend to adopt a cyclic structure was observed. The more stable configuration of the adsorbed tetramer has a geometrical structure similar to that of the free tetramer. The properties of the aggregates have been monitored by computing adsorption energies, interaction energies, NBO charges, and the optimal geometry. The adsorption energy per component molecule of the methanol n-mer is always greater than that of only one molecule. The interaction energy between methanol molecules is related to the presence of dipolar interactions. They act directly between the molecules or are mediated through the substrate. Our theoretical results suggest that the methanol monolayer should have a compact structure. A very good agreement was obtained with the experimental data.