The Crystal Structure of Rare-Earth Impurity Centers R3+ in MeF2: ab initio Calculation

Abstract
Ab initio calculations of the impurity centers R³⁺ (R = La – Lu) in CaF₂ were carried out. The calculations were performed by using hybrid functional which takes into account both local and nonlocal (at the Hartree – Fock formalism) exchange. The crystal structure of impurity centers was investigated. The distance “rare-earth ion – ligand”, the radial and angular coordinates of the ions at several coordination spheres near to the impurity ion are determined. Calculations were carried out in the program CRYSTAL17, designed to simulate periodic structures within the MO LCAO approach.

Keywords
rare-earth impurity centers, ab initio calculations, fluorides
Funding
This study was supported by the Ministry of Education and Science of the Russian Federation (project no. 3.9534.2017/8.9). Supercomputer “Uran” of IMM UB RAS was used in the calculations
УДК 538.911; 538.913

The Crystal Structure of Rare-Earth Impurity Centers R3+ in MeF2:ab initio Calculation