Structure modeling of terbium doped strontium-lanthanum borate

Terbium doped strontium-lanthanum borate, Sr3La2(BO3)4:Tb (SLB), was studied by semi-empirical computational approaches using PM6 parametrization and the SPARKLE model for lanthanide(III) (Ln(III)) cations. The focus of interest was on structural aspects, e.g. the cell parameters and distribution of dopant ions between various sites as a function of dopant concentration. The cell linear dimensions were calculated to decrease linearly with increasing dopant molar concentration. SLB offered two sites for the dopant. Calculations predicted that one of these sites should be preferred by the Tb(III) dopant. The optimized cell dimensions as well as the total energies differed for structures with dopant exclusively in site 1 or site 2. Computational predictions were tested against experimental results obtained for SLB synthesized by sol-gel method varying the dopant concentration. The agreement between experimental and computational results was found sufficiently promising to continue the computational studies.