Experimental Study and Analysis of Absorption Spectra of Ni2+ Ions in Nickel Orthoborate Ni3(BO3)2

Autor: A. D. Molchanova
Rok vydání: 2018
Předmět:
Zdroj: Physics of the Solid State. 60:1957-1965
ISSN: 1090-6460
1063-7834
DOI: 10.1134/s1063783418100219
Popis: The results of studies of the absorption spectra of nickel orthoborate Ni3(BO3)2 in the range of electronic d–d-transitions are reported. The obtained data are analyzed in the framework of the crystal field theory. The Ni2+ ions are located in two crystallographically nonequivalent positions 2a and 4f with point symmetry groups C2h and C2, respectively, surrounded by six oxygen ions forming deformed octahedra. The absorption spectra exhibit three intense bands corresponding to spin-resolved transitions from the ground state of nickel ion 3A2g (3F) to the sublevels of the 3T2g (3F), 3T1g (3F) and 3T1g (3P) triplets split by the spinorbit interaction and the rhombic component of the crystal field. At temperatures below 100 K, the spectra exhibit a thin structure, in which phonon-free lines can be distinguished. Comparison of the calculated frequencies of the zero-phonon transitions with the experimental data allows estimating parameters of the crystal field acting on the nickel ions in the 2a- and 4f-positions, as well as the parameters of electrostatic interaction between the 3d electrons and spin-orbit interaction constants.
Databáze: OpenAIRE