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Semiempirical Crystal Field Calculations for f N ‐Systems. III. Crystal Field Splitting and Jahn‐Teller Effect in Cubic (NEt 4 ) 4 U(NCS) 8 Crystal
Author(s) -
Mironov V. S.,
Rosov S. P.
Publication year - 1992
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221700216
Subject(s) - jahn–teller effect , tetragonal crystal system , ion , chemistry , crystal (programming language) , crystal field theory , crystallography , field (mathematics) , ground state , adiabatic process , crystal structure , condensed matter physics , atomic physics , physics , quantum mechanics , mathematics , organic chemistry , pure mathematics , computer science , programming language
The crystal field spectrum of 5f 2 ‐configuration of cubic U(NCS) 8 4−anion in (NEt 4 ) 4 U(NCS) 8 is calculated by using the new semiempirical many‐electron method, developed in previous papers. The Γ 5 ‐triplet is found to be the ground state of U(NCS) 8 4−anion. The T ⊗ (e g + t 2g (1)+ t 2g (2) ) Jahn‐Teller problem is studied quantitatively for U(NCS) 8 4−anion. It is shown that tetragonal Jahn‐Teller minima in the adiabatic potential of U(NCS) 8 4−are much deeper ( E JT = 78 cm −1 ) than the trigonal ones. The temperature dependence of the effective magnetic moment of the U 4+ ion in (NEt 4 ) 4 U(NCS) 8 is reproduced very well in the frame of modified Jahn‐Teller model suggesting simultaneous existence in (NEt 4 ) 4 U(NCS) 8 both, tetragonally compressed and elongated U(NCS) 8 4−anions arising due to Jahn‐Teller distortions and influence of cation vacancies, respectively.