2023/10/13 by Alexander V. Oleynichenko, Oleynichenko, Alexander V., Yu. V. Lomachuk +11 · 1 citation
Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic and Molecular Clusters (physics.atm-clus) #Chemical Physics (physics.chem-ph) #Cold Atom Physics and Bose-Einstein Condensates #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Solid-state spectroscopy and crystallography
paper · pdf · doi:10.48550/arxiv.2310.09240
openalex publication_date 2023/10/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A method to simulate local properties and processes in crystals with impurities via constructing cluster models within the frame of the compound-tunable embedding potential (CTEP) and highly-accurate \it ab initio relativistic molecular-type electronic structure calculations is developed and applied to the Ce and Th-doped yttrium orthophosphate crystals, YPO4, having xenotime structure. Two embedded cluster models are considered, the "minimal" one, YO8@CTEP\rm min, consisting of the central Y3+ cation and its first coordination sphere of eight O2- anions (i.~e. with broken P--O bonds), and its extended counterpart, Y(PO4)6@CTEP\rm ext, implying the full treatment of all atoms of the PO43- anions nearest to the central Y3+ cation. CTEP\rm min,ext denote here the corresponding cluster environment described within the CTEP method. The relativistic Fock-space coupled cluster (FS RCC) theory is applied to the minimal cluster model to study electronic excitations localized on Ce3+ and Th3+ impurity ions. Calculated transition energies for the cerium-doped xenotime are in a good agreement with the available experimental data (mean absolute deviation of ca.0.3 eV for 4f→5d type transitions). For the thorium-doped crystal the picture of electronic states is predicted to be quite complicated, the ground state is expected to be of the 6d character. The uncertainty for the excitation energies of thorium-doped xenotime is estimated to be within 0.35 eV. Radiative lifetimes of excited states are calculated at the FS RCC level for both doped crystals. The calculated lifetime of the lowest 5d state of Ce3+ differs from the experimentally measured one by no more than twice.