Intra-octahedral distortion on lamellar potassium niobate K 4 Nb 6 O 17 : a periodic DFT study of structural, electronic and vibrational properties.

Autor: Souza JKD; NPE-Lacom, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900, João Pessoa, PB, Brazil., Duarte TM, Dos Santos IMG, Sambrano JR, Maia ADS, Dos Reis Albuquerque A
Jazyk: angličtina
Zdroj: Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2020 Aug 07; Vol. 22 (29), pp. 16562-16570. Date of Electronic Publication: 2020 May 06.
DOI: 10.1039/d0cp01581d
Abstrakt: Structural, electronic and spectroscopic properties of the anhydrous K 4 Nb 6 O 17 niobate were investigated in the bulk phase using periodic density functional theory (DFT) calculations with global hybrid (B3LYP) and also including dispersion corrections (B3LYP-D3). The degree of native distortion of different niobium octahedra (here named [NbO 6-x ], or [NbO 6 ] d ) were quantified in terms of the effective coordination number (ECoN) and of other classical descriptors of local deformation and were correlated with the electronic structure. The effect of intrinsic deformation was also examined using the quantum theory of atoms in molecules and crystals (QTAIMC), density of states and charge analyses. The nature of the atom-atom interactions was classified by the ratio of the potential to the kinetic energy density at the bcp (3,-1): |V(r bcp )|/|G(r bcp )|, demonstrating that intraoctahedral Nb-O interactions are well characterized as "transit bond" (between the pure covalent and ionic chemical bonds). The vibrational spectra (infrared and Raman intensities) were fully characterized and discussed, correlating the frequencies with the intraoctahedral distortion.
Databáze: MEDLINE