Abstract
A striking difference in the clustering and reaction efficiencies of Ti+ with methanol and acetonitrile has been observed following the reactions of laser-generated Ti+ with preformed clusters of methanol and acetonitrile. Evidence for a catalytic conversion of methanol dimer into dimethyl ether by TiO+ is presented. The resulting sequence TiO+(CH3OCH3)(CH3OH)(n) shows enhanced ion intensity at n = 4 suggesting the formation of a stable octahedral structure TiO+(CH3OCH3)(CH3OH)(4). In contrast to methanol, the major reactions of Ti+ with acetonitrile clusters involve simple clustering producing Ti+(CH3CN)(n). The difference in reactivity is attributed to the formation of TiO+ through the reactions of Ti+ with methanol clusters. (C) 1999 Elsevier Science B.V. All rights reserved.