title: Studies of EPR spectra and defect structure for Er³⁺ ions in BaF₂ and SrF₂ crystals.
abstract: The local lattice structure and electron paramagnetic resonance (EPR) spectra have been studied systematically by diagonalizing 364 × 364 complete energy matrices for a f(11) ion in a trigonal ligand-field. By simulating the calculated Stark levels and EPR parameters to the experimental results, the shift parameters are determined for Er(3+) ions in BaF(2) and SrF(2). The results show that the trigonal center is attributed to an interstitial F(-) ion located at the [111] axis of the cube, and the nearest ligand close to the charge compensator has a displacement towards central ion by 0.042Å for L center in BaF(2):Er(3+) and 0.026Å for J center in SrF(2):Er(3+), respectively. Moreover, the relationships between g-factors and shift parameter ΔZ as well as orbit reduction factor k' are discussed.
authors.affiliation: Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Kuang
authors.forename: Ai-Jie
authors.initials: AJ
authors.lastname: Mao
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Li
mesh_terms: D017609:Barium Compounds / Q000737:chemistry*; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy; D004871:Erbium / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*
chemical_list: D017609:Barium Compounds; D007477:Ions; D004871:Erbium; C055150:barium fluoride; D005459:Fluorides; D013324:Strontium