Electronic structure and electric-field gradients of crystalline Sn(II) and Sn(IV) compounds

The electronic structures of clusters representing crystalline compounds of Sn(II) and Sn(IV) were investigated, employing the first-principles discrete-variational method and local-density theory. Densities of states and related parameters were obtained and compared with experimental measurements and with results from band-structure calculations. Effects of cluster size and of cluster truncated bonds are discussed. Electric-field gradients at the Sn nucleus were calculated; results are analyzed in terms of the charge distribution and chemical bonding in the crystals.