INTERACTION OF CH3OH WITH ALPHA-MOO3 FINITE CLUSTERS, A THEORETICAL-STUDY

Methanol chemisorption on various faces of molybdenum trioxide are stu died by EHT calculations with model clusters. Both energy values and o verlap populations show that molecular and dissociative chemisorption can be envisaged. At a distance fixed at 1.75 Angstrom between the sur face molybdenum and the methanol oxygen, the stability of the molecula r chemisorption complex increases as we pass from the (100) face to th e (001) and (010) ones, if the last-mentioned presents an oxygen vacan cy before methanol chemisorption. On the (100) and (001) faces contain ing unsaturated oxygen, dissociative chemisorption leads to states of greater stability than molecular chemisorption. In contrast, if the su perficial oxygen involved is saturated, the states obtained are less s table.