Dynamics of interstitial H-2 in crystalline silicon - art. no. 075216

摘要

The dynamics of interstitial H-2 and its isotopes in crystalline silicon have been studied by using a potential-energy function for the molecule that consists of the superposition of potentials for two separated hydrogen atoms as generated from the quantum-mechanical calculations of Porter, Towler, and Needs. The rotational properties were calculated using the approach of Martin and Fowler and the vibrational properties of the molecules as a whole were obtained. The results of these calculations indicate nearly free rotational motion, consistent with shallow rotational potentials. Confinement of the molecules leads to center-of-mass vibrations of a few hundred wave numbers and dynamical "off-centeredness" that breaks tetrahedral symmetry and allows purely vibrational transitions to occur. This approach has also been used to investigate tetrahedral interstitial H-2 adjacent to a bond-centered oxygen atom. The results of these calculations provide a framework for understanding the rovibrational properties of H-2 and O-H-2 and their isotopes, including experiments involving uniaxial stress. [References: 46]