BENZENE SI(100) - METASTABLE CHEMISORPTION AND BINDING STATE CONVERSION/

Scanning tunneling microscopy (STM) has been used to investigate the a dsorption of benzene on the Si(100)(2 x 1) surface. At room temperatur e two types of bonding configurations are observed; on-top of a single Si dimer and bridging two dimers. Upon dosing the single dimer state is populated preferentially but is seen to be metastable with respect to the bridging configuration, in agreement with semi-empirical quantu m cluster calculations. The single dimer to bridge conversion is activ ated, with a barrier of 0.95 eV. The single dimer state can be re-popu lated via a process assisted by the STM tip. (C) 1998 Published by Els evier Science B.V.