Molecular orbital model of optical centers in bismuth-doped glasses

Spectroscopic properties of optical fibers with a bismuth-doped silicate glass core are explained on the basis of molecular orbital theory and a solution of the Schrödinger equation, which takes into account the exchange, the spin-orbital, and the glass field potential interactions of s, p, and d electron shells of bismuth with s(σ), p(σ), and p(σ) orbits of oxygen atoms. The approach can explain the IR luminescence properties of other optical centers formed by other atoms with the same structure of electron shells as the bismuth atom. The model of transitions based on intramolecular charge transfer between molecular orbital and metallic states is proposed.