Open AccessСтруктура и динамика решетки тетрагональных германатов R-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- (R=Tb-Lu, Y): ab initio расчет
Author(s) -
Виталий Сергеевич Рюмшин,
V. A. Chernyshev
Publication year - 2021
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2021.06.50943.030
Subject(s) - germanate , yttrium , ab initio , raman spectroscopy , tetragonal crystal system , ab initio quantum chemistry methods , phonon , density functional theory , materials science , spectral line , crystal structure , chemistry , ion , crystallography , computational chemistry , condensed matter physics , physics , molecule , optics , organic chemistry , astronomy , metallurgy , oxide
Within the framework of density functional theory, an ab initio calculation was carried out to study the crystal structure, phonon spectrum and elastic constants of a series of rare-earth germanates, including yttrium germanate R2Ge2O7 (R = Tb-Lu, Y) with tetragonal structure. The frequencies and types of fundamental vibrations as well as the intensities of the IR and Raman modes were determined. The degree of participation of ions in each mode was determined from the analysis of the displacement vectors obtained from the ab initio calculation. The calculations were performed for the first time. The corresponding experimental data for the entire series, with the exception of the IR and Raman spectra of yttrium germanate, are absent. The calculations made it possible to interpret and supplement available in the scientific articles results of measurements of the IR and Raman spectra of yttrium germanate Y2Ge2O7.