Supercluster quantum-chemical approach to the Si(111)7x7 surface. 2. Charge and spin distribution

The paper continues to present the results of an extended quantum-chemical study of the Si(111)7 X 7 surface unit cell. It addresses the charge and spin density distributions over the unit cell atoms while the previous paper, Part I (Phys. Low-Dim.Struct., 11/12 (1996) 1) was related to the surface reconstruction motives as well as to energy and structure of different equilibrium configurations. Two lowest-energy configurations related to the triplet and singlet spin states and full consistent with the DAS model are analyzed in the study. A ferromagnetic behaviour of the triplet configuration is discussed.