Possibility of charge transfer between dimer atoms on Si(100)-(2×1)

A precision determination of the number of dimer atoms on the Si(100)-(2×{}1) surface which contribute to the 2p core-level shift as measured by high-resolution photoemission is possible with an in situ comparison with Si(111)-(7×{}7). By correlating distinct features of the Si(111)-(7×{}7) spectrum with the known structural features of the (7×{}7) surface, the number of surface atoms which contribute to the Si(100)-(2×{}1) 2p core shift is 0.92±{}0.07 monolayers. Implications regarding the symmetry of the valence charge distribution about the dimers are addressed.