Abstract
The vibrational modes of 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 interstitial site, oriented along [011] 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 site. It is suggested that Raman-active modes around 4158 are due to molecules within voids.
- Received 25 February 1998
DOI:https://doi.org/10.1103/PhysRevB.57.R12666
©1998 American Physical Society