Structure and bonding of liquid Se

Ab initio molecular dynamics based on density functional theory has been used to study liquid Se at three temperatures: 570, 870 and 1370 K. The calculated g(r) is in very close agreement with neutron diffraction data, except in the region of the first minimum at . We have examined the effect of including gradient corrections in the density functional description, and we find that they give a substantial improvement in the agreement with experiment near the first minimum. We analysed the bonding topology and we find a significant fraction of onefold- and threefold-coordinated Se atoms at the highest temperature.