In Be-doped MgO crystals a new V center was discovered whose physical properties differ significantly from those of other V centers. The center could be observed by means of EPR at room temperature; the shift of its g-factor from the free electron value was about 1.6 times smaller than that of a VOH center, the optical absorption band was shifted by about 1eV to higher energies, and the thermal destruction of the center through the loss of a hole took place at about 400K. The axial symmetry of the center and the hyperfine structure of its electron paramagnetic resonance spectrum suggested that the center had the form: Be2+-O--vc-OH-. The specific physical properties of the VOH-Be center were explained by an interaction of the effective electric dipole, created by the off-center position of the Be2+ ion substituting for the Mg2+, with the nearby localized hole.

VOH-Be - a New and Unusual Member in the Family of V Centers. S.A.Dolgov, V.Isakhanyan, T.Kärner, A.Maaroos, S.Nakonechnyi: Journal of Physics - Condensed Matter, 2002, 14[38], 8881-8