Symmetry of molecular H-2 in Si from a uniaxial stress study of the 3618.4cm(-1) vibrational line

Uniaxial stress has been used in conjunction with vibrational spectroscopy to probe the structure and microscopic properties of interstitial H-2 in Si . The stress splitting pattern observed for the 3618.4 cm(-1) line assigned to H-2 is consistent with triclinic (C-1) symmetry of a static center. The piezospectroscopic tensor determined in these experiments suggests a near [100] orientation for the H-2 molecular axis. The low symmetry that has bee n found in these experiments on the 3618.4 cm(-1) line is unexpected.