A comparative study of thermomechanical characteristics of Si34 and Si46

A spherically averaged intermolecular potential type Lennard-Jones is used within molecular dynamics simulation in order to investigate the thermomechanical properties of silicon in the clathrates structures. This two-body potential describes well the intermolecular interaction between Si-34-Si-34 and Si-46-Si-46. Results show that the diamond structure of silicon remains stable than the clathrates ones, although the difference in energy is quite small. We have also found that the volume of Si-34 and Si-46 increases by about 17% compared to silicon in the diamond structure. Several thermodynamics quantities are given for both materials. (C) 2002 Elsevier Science B.V. All rights reserved.