Specific features of the electronic structure and spectral characteristics of the Gd<Subscript>5</Subscript>Si<Subscript>3</Subscript> compound

The electronic structure and optical properties of the hexagonal intermetallic compound Gd₅Si₃ are investigated. The spin-polarization calculation of the band spectrum is performed in the local spin density approximation, taking account for the strong electron correlations in the 4 f shell of a Gd ion (LSDA + U method). Optical constants of the compound in the wavelength range of 0.22–15 μm are determined by the ellipsometry technique and some spectral characteristics are calculated. The frequency dependence of optical conductivity in the light quantum absorption region is analyzed on the basis of the calculated electron density of states.     

Specific features of the behavior of the optical properties of TbNi<Subscript>5 − <Emphasis Type="Italic">x</Emphasis></Subscript>Cu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> intermetallic compounds

The optical properties of the TbNi_{5 ? x} Cu _x intermetallic compounds have been investigated in the spectral range 0.08–5.64 eV by the ellipsometric method. It is shown that substitution of nickel for copper atoms leads to a significant change in the frequency dependence of the optical conductivity; this change is related to modification of the electronic spectrum. The formation of a new interband absorption band has been revealed, whose intensity increases with an increase in the copper content. The concentration dependences of the plasma and relaxation frequencies of conduction electrons in the compounds under study are determined. Self-consistent calculation of the electronic structure of the TbNi₅ binary compound has been performed in the approximation of local electron spin density. The electron density of states for two spin projections and the optical conductivity of this compound have been calculated.     

Magnetic properties,electronic structure,and optical properties of the filled skutterudite BaFe4Sb12

The magnetic properties, electronic structure, and optical properties of the filled skutterudite BaFe₄Sb₁₂ are calculated by the first-principles full-potential linearized augmented plane wave (FPLAPW) plus local orbital method. It is found that the local spin density approximation (LSDA) method appears more accurate than the generalized gradient approximation (GGA) method in calculating the electronic structures and optical properties of this compound. Furthermore, our calculated lattice constant and spin magnetic moments with the LSDA method are in overall better agreement with experiment. In contrast with recent experiment, our calculations are in good agreement with experimental reflectivity spectra and optical conductivity spectrum.     

Electronic structure of the TbMn<Subscript>0.33</Subscript>Ge<Subscript>2</Subscript> compound: Band calculation and optical experiment

The results of the investigation of the electronic structure and optical properties of the TbMn_0.33Ge₂ compound have been presented. The spin-polarized calculations of the band spectrum have been performed within the framework of the local spin density approximation (LSDA) with a correction for strong correlations in the 4f shell of the rare-earth ion (the LSDA + U method). The optical constants have been measured using the ellipsometric method and a number of spectral and electronic characteristics of the compound under investigation have been determined over a wide range of wavelengths. The interband part of the experimental dependence of the optical conductivity has been interpreted using the results of the calculation of the electron density of states.     

Optical spectroscopy and electronic structure of the Er5Ge3 compound

The results of the study of the optical properties and electronic structure of the Er₅Ge₃ compound have been presented. In the wavelength range of 0.22–15 μm (0.083–5.64 eV), the optical constants have been measured, and the spectral and electronic characteristics have been determined. The spin-polarization calculations of the band spectrum have been performed in the local electron spin density approximation (LSDA) with a correction for strong correlations in the 4f shell of the rare-earth atom (LSDA + U method). The main features of the experimental dispersion dependence of the optical conductivity in the region of quantum light absorption have been interpreted based on the results of calculations of the electron density of states.     

Electronic Structure of GdCuGe Intermetallic Compound

The electronic structure of GdCuGe intermetallic compound has been studied. Spin-polarized energy spectrum calculations have been performed by the band method with allowance for strong electron correlations in the 4f-shell of gadolinium ions. Antiferromagnetic ordering of GdCuGe at low temperatures has been obtained in a theoretical calculation, with the value of the effective magnetic moment of gadolinium ions reproduced in fair agreement with experimental data. The electronic density of states has been analyzed. An optical conductivity spectrum has been calculated for GdCuGe; it reveals specific features that are analogous to the ones discovered previously in the GdCuSi compound with a similar hexagonal structure.     

Effect of copper and cobalt impurities on the electronic structure and optical spectra of the intermetallic compound PrNi5

The electronic structure and optical properties of the intermetallic compound PrNi₅ and their evolution during the substitution of copper or cobalt atoms for nickel atoms have been investigated. The band spectra of the studied compounds have been calculated in the local spin density approximation corrected to account for strong electron-electron interactions in the 4f shell of the rare-earth ion (LSDA + U method). The dispersion relations of the optical conductivity in the interband light absorption region have been interpreted using the results of calculations of the electron density of states.     

Electronic and Spectral Properties of RRhSn (R = Gd,Tb) Intermetallic Compounds

The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.     

Photodesorption of rubidium atoms from a sapphire surface

The optical properties of the GdRhGe compound have been investigated in a wide spectral range by ellipsometry. Self-consistent calculations of the electronic structure have been performed within the local electron spin density approximation with a correction to strong electron interactions in the 4f shell of gadolinium ions (LSDA+U method). The experimental dispersion relation of the optical conductivity in the region of interband light absorption is interpreted based on the results of calculating the electron densities of states.     

Optical absorption and electronic structure of intermetallic compound RuIn3

The optical properties of intermetallide RuIn₃ are investigated by ellipsometry in the spectral range of 0.22–10 μm. The experimental data point to the existence of an energy gap of about 0.5 eV in the electronic spectrum of the compound. The density of the electron states and interband optical conductivity are calculated in terms of the density functional theory. The experimental and theoretical spectra of the optical conductivity are compared. It is found that the formation of basic absorption bands is caused by interband transitions of electrons of the d-band of Ru and p-band of In.     

Role of Fe and Co in optical conductivity and electronic structure of TbNi4Fe and TbNi4Co

Optical properties of two intermetallic compounds TbNi₄Fe and TbNi₄Co have been studied employing ellipsometry in a spectral range 0.22–15 μm to reveal their characteristic features in comparison with the parent compound TbNi₅. The electronic structure of TbNi₄Fe and TbNi₄Co was calculated within the LSDA + U method (local spin density approximation with Hubbard U-correction). Based on the calculated electronic structure results, the theoretical optical conductivity was calculated and used to interpret experimental conductivity in the range of interband optical absorption.     

Ab initio calculations of the elastic, electronic, optical, and vibrational properties of PdGa compound under pressure

The structural, elastic, electronic, optical, and vibrational properties of cubic PdGa compound are investigated using the norm-conserving pseudopotentials within the local density approximation (LDA) in the framework of the density functional theory. The calculated lattice constant has been compared with the experimental value and has been found to be in good agreement with experimental data. The obtained electronic band structures show that PdGa compound has no band gap. The second-order elastic constants have been calculated, and the other related quantities such as the Young’s modulus, shear modulus, Poisson’s ratio, anisotropy factor, sound velocities, and Debye temperature have also been estimated. Our calculated results of elastic constants show that this compound is mechanically stable. Furthermore, the real and imaginary parts of the dielectric function and the optical constants such as the electron energy-loss function, the optical dielectric constant and the effective number of electrons per unit cell are calculated and presented in the study. The phonon dispersion curves are also derived using the direct method.     

Spectroscopic analysis,AIM, NLO and VCD investigations of acetaldehyde thiosemicarbazone using quantum mechanical simulations

The prepared Acetaldehyde thiosemicarbazone (ATSC) have been investigated by both the experimental and theoretical methods; through this work, the essentiality of elucidation of molecular fragments source linear and non-linear optical properties was explored. The stability of the structure and entire calculations have been performed on HF and B3LYP methods with 6-311++G(d,p) level of basis set. The Mulliken charge profile, electronic, optical and hyper polarizability analyses have been carried out in order to evaluate nonlinear optical (NLO) performance of the present compound. The exact optical location of the ATSC was determined by executing UV–Visible calculations on TDSCF method. The existence of the molecular group for the inducement and tuning of NLO properties were thoroughly investigated by performing fundamental vibrational investigation. The optical energy transformation among frontier molecular levels has been described in UV–Visible region. The Gibbs energy coefficient of thermodynamic functions was monitored in different temperature and it was found constant irrespective of temperatures. The appearance of different chemical environment of H and C was monitored from the ¹H and ¹³C NMR spectra. The vibrational optical polarization characteristics with respect to molecular composition in the compound have been studied by VCD spectrum. The bond critical point, Laplacian of electron density, electron kinetic energy density and total electron energy density have calculated and analysed using AIM study.     

三元化合物ZnVSe2半金属铁磁性的第一性原理计算

采用基于密度泛函理论(DFT)框架下的第一性原理平面波赝势(PWP)方法,结合广义梯度近似(GGA),对三元化合物ZnVSe₂晶体的电子结构进行了计算,分析了ZnVSe₂晶体自旋极化的能带结构、电子态密度、电荷布居、磁矩等.计算结果表明,三元化合物ZnVSe₂会产生自旋极化状态,能带结构和态密度显示为半金属特征,表现出显著的铁磁性行为,具有高达近100%的传导电子自旋极化率,其半金属能隙为0.443eV,理论预测其可能是一种具有一定应用潜能 关键词： 2')" href="#">ZnVSe₂ 平面波赝势方法 半金属铁磁性 第一性原理     

Thermodynamic Stability,Half-Metallic and Optical Properties of Sc2CoSi [001] Film:a DFT Study

The electronic and optical characteristics of the Sc2 CoSi Heusler with L21 structure and also the surface effect on electronic and optical properties, and the ?lms thermodynamic stability of the [001] direction in four cases including:Sc-Sc, Sc-Co, Sc-Si and Co-Si terminations are studied using the ?rst principles calculations(FPLAPW) within the framework of the density functional theory(DFT). The band structure calculations represent the ferromagnetic halfmetallic properties with 100% spin polarization and 0.54 e V indirect gap in spin down for Sc2 CoSi bulk with optimized lattice parameters of 6.25 A?. The total magnetic moment obtained for this compound is-1.0 μB, which is in accordance with Slater-Pauling rule. The half-metallic(HM) behavior by 100% spin polarization at Fermi level is occurred in the Sc-Si termination with a 0.32 eV gap in down spin. The optical responses have been calculated for the bulk and ScSi termination by a red shift in these parameters and the metallic treatments have been increased. According to the thermodynamic phase diagrams, it is shown the Sc-Si and Sc-Sc terminations are more stable than other terminations.     

层状氧化钼的电子结构、磁和光学性质第一原理研究

按照基于自旋密度泛函理论的赝势平面波第一原理计算方法,理论研究了两种层堆叠结构氧化钼(正交和单斜MoO_3)的电子结构、磁性和光学特性,探讨其作为电致变色材料或电磁材料在光电子器件中的技术应用.采用先进的半局域GGA-PW91和非局域HSE06交换相关泛函精确计算晶体结构和带隙宽度.计算得出较低密排面解离能,表明两种层状氧化钼的单片层很容易从体材料上剥落.能带结构和投影态密度分析表明:导带底和价带顶电子态主要来自于层平面方向成键的原子轨道,呈现典型的二维电子结构特征.无缺陷的MoO_3块体材料具有明显的磁矩,O空位会导致磁矩增加;由Mo原子和顶点氧原子产生的亚铁磁耦合磁矩是MoO_3层状材料磁性的主要来源;层状氧化钼在可见光区具有明显的光吸收响应,光吸收谱表现出显著的各向异性并在带电时发生明显的蓝移或形成新的低频可见光吸收峰.计算结果证明层状氧化钼具有明显的电致变色和磁控性能,为设计高性能电磁或光电子功能材料提供了理论依据和技术数据.     

新型稀磁半导体Mn掺杂LiZnP的电子结构和光学性质

采用基于密度泛函理论的第一性原理计算方法,对纯LiZnP、Mn掺杂LiZnP、Li过量和不足时Mn掺杂LiZnP体系进行了几何结构优化,计算并分析了体系的电子结构、半金属性、态密度及光学性质.结果表明:LiZnP新型稀磁半导体可以实现自旋和电荷注入机制的分离.Mn的掺入使体系产生自旋极化杂质带,自旋极化率达到100%,表现出半金属铁磁性,且体系性质受Li计量数的影响.当Li不足时杂质带宽度增大,半金属性增强,居里温度提高,形成能最低.进一步比较光学性质发现:Mn掺入后体系光学性质没有明显变化,但随Li的化学计量数的改变,介电函数虚部会在低能区中出现新的介电峰,同时复折射率函数对低频电磁波吸收明显加强,且能量损失在Li过量时最小.     

新型稀磁半导体Mn掺杂LiZnP的电子结构和光学性质

采用基于密度泛函理论的第一性原理计算方法,对纯LiZnP、Mn掺杂LiZnP、Li过量和不足时Mn掺杂LiZnP体系进行了几何结构优化,计算并分析了体系的电子结构、半金属性、态密度及光学性质。结果表明：LiZnP新型稀磁半导体可以实现自旋和电荷注入机制的分离。Mn的掺入使体系产生自旋极化杂质带,自旋极化率达到100%,表现出半金属铁磁性,且体系性质受Li计量数的影响。当Li不足时杂质带宽度增大,半金属性增强,居里温度提高,形成能最低。进一步比较光学性质发现：Mn掺入后体系光学性质没有明显变化,但随Li的化学计量数的改变,介电函数虚部会在低能区中出现新的介电峰,同时复折射率函数对低频电磁波吸收明显加强,且能量损失在Li过量时最小。     

pH自旋探针分子的ESR波谱性质和量子化学研究─pH自旋探针应用研究之二

系统研究了咪唑类氮氧自由基作为pH自旋探针的ESR波谱特性．用量子化学方法AM1研究了pH自旋探针分子的几何结构、电子结构及电子自旋密度分布．aN理论值与实验结果基本一致．得到了pka值与电子密度关系曲线．指出了它们在生命科学中的应用前景．     

Ab initio study of electronic structure and magnetic properties of copper (II) terephthalate

The first principles within the full potential linearized augmented plane wave (FP-LAPW) method was applied to study the compound of Cutp(OH₂)₂. The density of states, the electronic band structure and the spin magnetic moment are calculated. The calculations reveal that the compound has a ferromagnetic interaction arising from the bridging water molecule. The spin magnetic moment 1.0μ_B per molecule mainly comes from the Cu ion with little contribution from O, C anion.