Theoretical study of the Cl-passivated Si(111) surface

The Cl-passivated Si(111) surface is studied using density functional theory, in conjunction with the B3LYP functional and the cluster model. We compute the Si-Cl frequency and the Si-Cl bond energy for R3SiCl, and the abstraction barrier for the reaction R3SiCl + H --> R3Si + HCl using the B3LYP approach. We calibrate the B3LYP bond energy and the abstraction barriers using the values obtained using the G2MP2, G2 and CCSD(T) approaches. Our computed B3LYP Si-Cl frequency of 555 cm(-1) is in good agreement with the experimental value of 588 cm(-1). The shift in the Si-Cl frequency as surface chlorine is added to the cluster agrees with experimental observations. (C) 1999 Elsevier Science B.V. All rights reserved.