Zhuravlev Yuri, Atuchin Victor
Department of General and Experimental Physics, Kemerovo State University, 650000 Kemerovo, Russia.
Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, 630090 Novosibirsk, Russia.
Molecules. 2022 Oct 12;27(20):6840. doi: 10.3390/molecules27206840.
The present work applied the methods of density functional theory and the van der Waals interaction PBE + D3(BJ) on the basis of localized orbitals of the CRYSTAL17 package. It featured the effect of interactions between structural elements of fluorocarbonates ABCOF (A: K, Rb, Cs; B: Mg, Ca, Sr, Zn, Cd) on their elastic and vibrational properties. The hexagonal structures proved to consist of alternating ···B-CO··· and ···A-F··· layers in planes , interconnected along axis by infinite chains ···F-B-F···, where cations formed polyhedra AOF and BOF. The calculations included the band energy structure, the total and partial density of electron states, the energy and band widths of the upper - and -states of alkali and alkaline-earth metals, as well as -zinc and cadmium. For hydrostatic compression, we calculated the parameters of the - and the linear compressibility moduli along the crystal axes and bond lines. We also defined the elastic constants of single crystals to obtain the Voigt-Reuss-Hill approximations for the elastic moduli of polycrystalline materials. The study also revealed the relationship between the elastic properties and the nature of the chemical bond. Hybrid functional B3LYP made it possible to calculate the modes of normal long-wavelength oscillations, which provided the spectra of infrared absorption and Raman scattering. Intramolecular modes and with one or two maxima were found to be intense, and their relative positions depended on the lengths of nonequivalent C-O bonds.
本工作基于CRYSTAL17软件包的定域轨道，应用密度泛函理论方法和范德华相互作用PBE + D3(BJ)。研究了氟碳酸盐ABCOF（A：K、Rb、Cs；B：Mg、Ca、Sr、Zn、Cd）结构单元之间的相互作用对其弹性和振动性质的影响。结果表明，六方结构由平面内交替的···B - CO···和···A - F···层组成，沿轴通过无限长链···F - B - F···相互连接，其中阳离子形成多面体AOF和BOF。计算内容包括能带能量结构、电子态的总密度和分密度、碱金属和碱土金属以及锌和镉的上态和下态的能量和带宽。对于静水压力压缩，我们计算了沿晶体轴和键线的体模量和线性压缩模量参数。我们还定义了单晶的弹性常数，以获得多晶材料弹性模量的Voigt - Reuss - Hill近似值。该研究还揭示了弹性性质与化学键性质之间的关系。杂化泛函B3LYP使得计算正常长波振荡模式成为可能，这些模式提供了红外吸收光谱和拉曼散射光谱。发现具有一个或两个最大值且强度较大的分子内模式 和 ，它们的相对位置取决于不等价C - O键的长度。
