PHASE-TRANSITION IN SUPERIONIC CONDUCTOR AG2SE - A MOLECULAR-DYNAMICS STUDY

A computer simulation by a constant-temperature and constant-pressure molecular dynamics method has been applied to Ag2Se to investigate the low temperature phase transition between a superionic phase and a nonsuperionic phase. The pair-wise potential model used by Rino et al. to study the superionic and molten state of Ag2Se has been used. The low temperature structure obtained by the calculations is orthorhombic with a = 4.29, b = 6.82, c = 8.25 angstrom, and the space group is Pmnb. This is very similar to that observed experimentally, which is orthorhombic with a = 4.333, b = 7.062, c = 7.764 angstrom, and the space group, P2(1)2(1)2(1).