First-principles total-energy calculations revealed the microscopic structures of multivacancies, and their role in H incorporation. It was found that the hexavacancy and the decavacancy were stable, and that the stable multivacancies were either free from, or fully decorated with, H; depending upon the chemical potential. It was also found that the H-decorated multivacancy was capable of containing an additional H2 molecule. It therefore exhibited peculiar vibrational spectra that were related to the H.

Multivacancy and Its Hydrogen Decoration in Crystalline Si T.Akiyama, Y.Okamoto, M.Saito, A.Oshiyama: Japanese Journal of Applied Physics - 2, 1999, 38[12A], L1363-5