Modeling paramagnetic B2+ center in lithium triborate

Microscopic structure of paramagnetic defect (B2+ - centre) in LiB3O5 crystals was studied on the basis of cluster calculations made by the self-consistent method of scattered waves in the model of interstitial cluster. The data on electronic structure, constants of superfine interaction for three alternative models of B2+-center were obtained. As a result of comparison of the calculated and experimental data preference is given to the model in the framework of which B2+ - centre is formed in the process of electron capture on boron in interstitial position. 18 refs.; 2 tabs