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

The Cl-passivated Si(111) surface is studied using density functional theor y, in conjunction with the B3LYP functional and the cluster model. We compu te the Si-Cl frequency and the Si-Cl bond energy for R3SiCl, and the abstra ction barrier for the reaction R3SiCl + H --> R3Si + HCl using the B3LYP ap proach. We calibrate the B3LYP bond energy and the abstraction barriers usi ng the values obtained using the G2MP2, G2 and CCSD(T) approaches. Our comp uted B3LYP Si-Cl frequency of 555 cm(-1) is in good agreement with the expe rimental value of 588 cm(-1). The shift in the Si-Cl frequency as surface c hlorine is added to the cluster agrees with experimental observations. (C) 1999 Elsevier Science B.V. All rights reserved.