Abstract
A formula for calculating the spin density of the U2-center has been obtained by considering the mixing of the configuration having H− and a hole in the host crystal and the effect of the orthogonalization of the core orbitals between neighboring ions. For the numerical calculation of the g-shifts and hyperfine structure constants of the U2-center, the problem is reduced to the one-hole picture in which the ground state wave function is expressed by an LCAO molecular orbital. It is pointed out that the effect of the configuration mixing plays an important role in producing the smaller hyperfine splitting due to proton in the U2-center than that in the free hydrogen atom, However, the g-shifts and the superhyperfine constants are overestimated by this effect; the effect of the orthogonalization of the core orbitals on these quantities is discussed.