Luminescence et interaction phonon—électron dans le luminophore MgS:Bi3+. II. Théorie sur le mélange entre les états 3T1u et 3A1u

Theoretical considerations are made on the mechanism of the admixture between the 3T1u and 3A1u states of Tl+‐type ions, which is realized for Au− ions in alkali halides and Pb2+, Bi3+ ions in alkali‐earth chalcogenides. It is shown that the ordinary electric electron‐phonon interaction has no effect on the admixture between both the states. A new model containing the magnetic interaction with the localized τ1g vibrational mode is proposed in order to explain this admixture by the use of the two‐electron wave functions.