By carrying out photoluminescence spectroscopy in magnetic fields of up to 12T, it was shown that the very shallow iso-electronic centers, B41 (1.15090eV principal no-phonon line), which were created by the neutron irradiation of P-doped samples that had been grown in a H atmosphere had C3v symmetry. The structure of the energy levels of the excitons which were bound to these centers were explained, and the lifetimes and g-factors of the bound particles were determined.

A.S.Kaminskii, E.V.Lavrov, V.A.Karasyuk, M.L.W.Thewalt: Solid State Communications, 1996, 97[2], 137-42