Structure land 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 similar to 2.9 Angstrom. 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.