Structural and electronic properties of supercritical fluid selenium: an ab initio molecular-dynamics simulation

The structural and electronic properties of fluid Se are investigated by me ans of an ab initio molecular-dynamics simulation. It is shown that the sem iconductor-metal transition in fluid Se is successfully reproduced, and tha t this transition is closely related to the structural changes of the Se ch ains, i.e., the bond breaking and the rearrangement of the Se chains due to the interchain interaction. It is found by investigating the trajectory of each Se atom that, in the metallic state, the length of the local chains c hanges with time and the Se atoms diffuse as pairs of atoms, while, in the lower temperature semiconducting state, the Se atoms have meandering trajec tories which is because long Se chains are present. (C) 1999 Elsevier Scien ce B.V. All rights reserved.