A computational study of bond-breaking process of Cu-Si bond during ion sputtering of a Cu/Si(111) surface, based on molecular orbital theory

A theoretical approach based on molecular orbital theory has been provided. By applying this theory to a bond-breaking process. the ionization probabi lity of Cu adsobates sputtered from a "5 x 5"-Cu/Si(1 1 1) surface has been studied. Three important aspects have been confirmed: (1) importance of a long range electrostatic potential such as the image potential, (2) importa nce of the coulomb repulsive potential between the Cu 4s spin-up and spin-d own electron, and finally (3) acceleration and deceleration effects dependi ng on charge state, which is a result of the interplay of the molecular bon ding interaction and the long range electrostatic interaction. The measurem ents of ionization probability will provide us more information of the adia batic potential curves of the reactants from the surfaces. (C) 2001 Elsevie r Science B.V. All rights reserved.