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Ab initio Cluster Calculations of the Electric Field Gradients at the Nb Site in the LiNbO 3 Crystal
Author(s) -
Shelyapina M.G.,
Kasperovich V.S.,
Shchegolev B.F.,
Charnaya E.V.
Publication year - 2001
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/(sici)1521-3951(200105)225:1<171::aid-pssb171>3.0.co;2-0
Subject(s) - multipole expansion , niobium , quadrupole , ab initio , ab initio quantum chemistry methods , cluster (spacecraft) , basis set , coupled cluster , chemistry , atomic physics , electric field gradient , molecular physics , physics , computational chemistry , density functional theory , molecule , quantum mechanics , organic chemistry , computer science , programming language
Calculations of the electric field gradients at the niobium site for the LiNbO 3 crystal have been carried out within the temperature range 298 to 1505 K using the ab initio cluster approach. The influence of cluster size and basis sets on the niobium quadrupole coupling constant was considered. It was shown that the calculations for the minimal cluster (NbO 6 ) —7 using the TZV basis set for oxygen and the (14s8p7d) basis set augmented with two diffuse p‐functions (0.074 and 0.023) for the niobium yield a good agreement with experimental data. Results of the ab initio cluster calculations were compared with those obtained within the framework of the point‐multipole model.