The effects of uniaxial stresses, magnetic-field perturbation and H-D isotope substitution upon the luminescence at 1.151 and 1.138eV in crystalline material were studied. The 2 centers which were responsible for this luminescence were shown to have symmetries and atomic compositions that were similar to those predicted for H dimers. The centers created acceptor (-/0) levels near to the conduction-band minima, and were paramagnetically inactive in their neutral states. It was shown that the luminescence transitions which were associated with the diatomic H centers, B41 and B171, could be explained in terms of the recombination of excitons that were bound to iso-electronic acceptors.

A.N.Safonov, E.C.Lightowlers, G.Davies: Physical Review B, 1997, 56[24], R15517-20