Tight-binding molecular dynamics study of hydrogen molecule inside silicon crystal

Tight-binding molecular dynamics simulations were carried out to investigate the dynamics of a H₂ molecule within a silicon crystal using a cluster model. The global minimum of the H₂ molecule's configuration was found to be at the tetrahedral interstitial site along the (100) direction. This is in good agreement with the results of first-principles quantum calculations. The H₂ molecule was trapped at this site up to a temperature of 600 K. At 900 K, the H₂ molecule diffused into the silicon crystal through the hexagonal site of the silicon lattice while retaining the H-H bond. These results justify the stability of the H₂ molecule inside the silicon crystal and the possibility of diffusion of the H₂ molecule in the silicon crystal without dissociation.