Chain structure of liquid and amorphous selenium: tight-binding molecular-dynamics simulation

Tight-binding molecular-dynamics (TB-MD) simulation has been performed to study the properties on the microscopic scale of liquid and amorphous selenium at 375 and 760 K. Since a diagonalization of the tight-binding (TB) Hamiltonian matrix is time consuming calculation, we have made parallel computations in the simulation program to realize a long time simulation of 512 atoms up to the 10(5) time steps corresponding to the order of 10 ps. The result shows that the radial distribution function, which becomes zero at around 0.275 nm, agrees with experiments and the dihedral angle distribution function has a maximum around 0 degrees, a minimum at 30 degrees and a smaller maximum around 100 degrees. This tendency differs from a previous study either by the tight-binding Monte Carlo (TB-MC) simulation or by the first principle molecular-dynamics (MD) simulation. (C) 1999 Elsevier Science B.V. All rights reserved.