The vibrational modes of H 2 molecules in Si are found using a first-principles method and compared with recent experimental investigations. The isolated molecule is found to lie at a T d interstitial site, oriented along  and is infrared active. The rotational barrier is at least 0.17 eV. The molecular frequency is a sensitive function of cage size and increases to lie close to the gas value for cages about 50% larger than the T d site. It is suggested that Raman-active modes around 4158 cm − 1 are due to molecules within voids.
- isolated molecule
- rotational barrier
- Raman-active modes
Hourahine, B., Jones, R., Öberg, S., Newman, R. C., Briddon, P. R., & Roduner, E. (1998). Hydrogen molecules in silicon located at interstitial sites and trapped in voids. Physical Review B (Condensed Matter), 57(20), [R12666]. https://doi.org/10.1103/PhysRevB.57.R12666