Surface reaction of 1,2,-dichloroethylene on Si(100)-2 × 1: Importance of surface isomerization channel

The surface reactions of trans-1,2-dichloroethylene (DCE) on Si(100)-2 × 1 were theoretically investigated to study the effects of chlorine substitutions on surface reactions. As in the case of pristine ethylene, diradical as well as π-complex channels leading to [2 + 2] cycloaddition products were found. In general, chlorine substitution makes the former kinetically more favorable and also changes its stereochemistry. In addition to modifying those existing reaction channels, the chlorine substitution opens new subsequent low-energy pathways leading to the experimentally suggested mono- and dichlorinated adstructures. Their large stabilities with low kinetic barriers make them the major surface species. Current study demonstrates that substitutions not only have large effects on existing reaction channels, but also introduces new possibilities, significantly changing the overall surface reactions.