A new model for the structure of amorphous selenium

Publisher Website
Google Scholar
Abstract
It is shown that a reversal in the magnitude of two peaks in the density of electron states associated with the bonding p-band in trigonal, compared to amorphous, selenium can best be an interaction between lone-pair and bonding orbitals in the two structures. This interaction reverses its parity between a spiral and a ring structure. We conclude that amorphous selenium is likely to consist of two-fold coordinated structural units in which the sign of the dihedral angle either alternates or is random in sign as one proceeds from atom to atom. We are able, on energetic grounds, to rule out structures with a large change in magnitude of the dihedral angle. The hybridization present in each phase is also discussed.