A study on mechanisms of radical initiated surface chain reaction of ethylene molecule on the H-terminated Si(111) has been carried out by using density functional theory and ab initio molecular dynamic methods. On Si(111) surface, one of the crucial steps of the surface chain reaction, namely, the abstraction of a H atom from a nearby surface hydride unit, is found to have a somewhat smaller activation energy from the nearest silicon site than from the next nearest silicon site. Ab initio molecular dynamics shows that the H-abstraction on Si(111) surface is very easy to be obtained from the transition state. (c) 2007 Elsevier B.V. All rights reserved.