Cycloaddition chemistry on germanium(001) surfaces: the adsorption and reaction of cyclopentene and cyclohexene

The adsorption and reaction of two cyclic unsaturated hydrocarbons, cyclope ntene and cyclohexene, with the Ge(001) surface has been investigated. The subsequent surface interactions were followed by a variety of surface-sensi tive techniques. Bonding configurations were determined by photoelectron sp ectroscopy, infrared spectroscopy and scanning tunneling microscopy. The st rength of surface interactions was also monitored by temperature-programmed desorption. Cyclopentene and cyclohexene react with surface germanium-dime r bonds to yield reaction products that are consistent with a [2+2] cycload dition reaction. This reaction generates rows of the surface complex orient ed along the dimer-bond direction of the Ge(001) surface, which is easily o bserved by scanning tunneling microscopy. (C) 2000 Elsevier Science B.V. Al l rights reserved.