The Quantum Chemistry Calculation and Thermoelectricsof Bi-Sb-Te Series

The density junction theory and discrete variation method ( DFT - DVM) was used to study correlation between composition, structure, chemical bond, and property of thermoelectrics of Bi-Sb-Te series. 8 models of Bi20-xSbxTe32(x = 0,2,6,8,12,14,18 and 20) were calculated. The results show that there is less difference in the ionic bonds between Te( I)-Bi(Sb) and Te(Ⅱ)-Bi(Sb) , but the covalent bond of Te(Ⅰ)-Bi( Sb ) is stronger than that of Te(Ⅱ)-Bi( Sb ) . The interaction between Te(Ⅰ) and Te(Ⅰ) in different layers is the weakest and the interaction should be Van Der Wools power. The charge of Sb is lower than that of Bi, and the ionic bond of Te-Sb is weaker than that of Te-Bi. The covalent bond of Te-Sb is also weaker than that of Te-Bi. Therefore, the thermoelectric property may be imfiroved by adjusting the electrical conductivity and thermal conductivity through changing the composition in the compounds of Bi-Sb-Te. The calculated results are consistent with the experiments.

STUDIES OF QUANTUM CHEMISTRY CALCULATION ON VALENCE-BOND STRUCTURE AND HYDRATION ACTIVTY OF C_(12)A_7

The structure, chemical bonds and hydra-tion activity of C12A were studied by SCC-DV-Xa method of computational quantum chemistry. The calculated results show that Ca-O bond will be first broken off when C12A hydrates, the reactivity of Al(2)O4 tetrahedron is superior to that of Al(1)O4 tet, thedron and the rupture of the Al-O-Al chain composed of two types of AlO4 tetrahedra under the action of water lies in the very weak Al(2)-O(2) bonds. the Al-O bond strength of C12A7 is between C3A and C11A7·CaF2.

Investigation of the Short-Time Photodissociation Dynamics of Furfural in S2 State by Resonance Raman and Quantum Chemistry Calculations

Raman(resonance Raman,FT-Raman),IR and UV-visible spectroscopy and quantum chemistry calculations were used to investigate the photodissociation dynamics of furfural in S2 state.The resonance Raman(RR)spectra indicate that the photorelaxation dynamics for the S0→S2 excited state is predominantly along nine motions:C=O stretchν5(1667 cm-1),ring C=C antisymmetric stretchν6(1570 cm-1),ring C=C symmetric stretchν7(1472 cm-1),C2-O6-C5 symmetric stretch/C1-H8 rock in planeν8(1389 cm-1),C3-C4 stretch/C1-H8 rock in planeν9(1370 cm-1),C5-O6 stretch in planeν12(1154 cm-1),ring breathν13(1077 cm-1),C3-C4 stretchν14(1020 cm-1),C3-C2-O6 symmetric stretchν16(928 cm-1).Stable structures of S0,S1,S2,T1 and T2 states with Cs point group were optimized at CASSCF method in Franck-Condon region there are S2/S1 conical intersection was found by state average method and RR spectra.

Structure and Quantum Chemistry Study on Hexaacetyl D-Mannose Hydrazine

Hexaacetyl D-mannose hydrazine is one type of important intermediates in saccharide chemistry. In this paper, its single crystal was obtained and furthermore, X-ray diffraction and quantum chemistry calculation were performed. It belongs to orthorhombic system, space group P212121, with a=16.267（3）, b=19.263（3）, c=7.1948（12）A, Mr=446.41, Dc=1.315 g/cm^3, V=2254.5（6）A^3 and Z=4. Meanwhile, the experimental results also provide information for designing a kind of molecular switch based on the mannose nitrogenous derivatives.

The Application of SCC-DV-X_a Computational Method of Quantum Chemistry in Cement Chemistry

It has been explored why quantum chemistry is applied to the research field of cement chemistry. The fundamental theory of SCC-DV-Xα computational method of quantum chemistry is synopsized. The results obtained by computational quantum chemistry method in recent years of valence-bond structures and hydration activity of some cement clinker minerals, mechanical strength and stabilization, of some hydrates are summarized and evaluated. Finally the prospects of the future application of quantum chemistry to cement chemistry are depicted.

Synthesis,Crystal Structure and Quantum Chemistry of the Complex [Cu(p-FBA)_2(phen)(H_2O)]

A novel metal-organic complex Cu（p-FBA）2（phen）（H2O） （p-FBA = p-fluorobenzoic acid,phen = 1,10-phenanthroline） has been synthesized and structurally characterized by X-ray single-crystal diffraction,elemental analysis and IR spectra. The crystal belongs to triclinic,space group P1 with a = 7.8043（7）,b = 10.4069（9）,c = 14.3658（13） ,α = 105.3170（10）,β = 96.877（2）,γ = 96.7580（10）o,V = 1103.56（17） 3,Mr = 539.96,Z = 2,Dc = 1.625 g/cm3,μ = 1.050 mm-1,F（000） = 550,the final R = 0.0324 and wR = 0.0952. In the crystal,the structure consists of discrete molecules containing a five-coordinate copper（Ⅱ ） in a distorted square pyramidal configuration. Intramolecular O-H···O hydrogen bonds,weak intermolecular C-H···O hydrogen bonds and π-π stacking link the molecules into a one-dimensional chain structure. The study on the title complex has been performed with quantum chemistry calculation by means of G03W package on the Lanl2dz basis set. The stabilities of the complex together with the orbital energies and composition characteristics of some frontier molecular orbitals have been investigated.

Quantum Chemistry Calculations on the Interaction Between Kaolinite and Gold

The density,function and discrete variation method (DFT - DVM) is used to study the interaction between kaolinite and gold. The correlation among the structure, chemical bond and stability is discussed. Several models are selected without gold and with gold in different directions and sites. The results show that the models with gold on the edge of kaolinite basal layer are more stable than those with gold above or under the layer, the models with gold near to [AlO2 (OH)(4)] octahedra are more stable than those with gold near to the vacancy without aluminium. The interaction between gold and the surface ions of kaolinite is strong enough to form the surface complexes.

Synthesis，Characterization，Crystal Structure and Quantum Chemistry Calculation of the Mixed Ligand Complexes ［Ln（CF_3COO）_3·（Phen）_2·（H_2O）_2］·CH_3COCH_3·H_2O

The complexes of rare earth trifluoroacetate with two 1, 10-phenanthroline Ln (CF_3COO)_3 ·(Phen )_2· CH_3COCH_3·3H_2O (Ln=La, Pr, Nd, Sm, Eu) have prepared in the mixed slovents of H_2O and CH_3COCH_3, and the single crystal Nd (CF_3COO)_3· (Phen )_2· CH_3COCH_3· 3H_2O was determined by four-circle X-ray diffractometer. The crystal is a monoclinic system with space group P2_1/n(14# ), a=0. 9253 ( 1 )nm , b=2. 1500 ( 2 ) nm , c=1.8981 ( 4 ) nm, β= 95. 28( 1 )°, V=3.760(8) nm￣3 , Z=4 , R=0. 035. The coordination number of Nd is 9 , and the coordination polyhedron of Nd atom is distorted tricapped triagonal prism. The electronic structures and chemical bonds of the complex Nd (CF_3COO)_3· (Phen )_2· CH_3COCH_3·3H_2O is studied by the spin unrestricted INDO method.

Quantum Chemistry Calculation on Oxygen and Nitrogen Adsorption in Carbon Nanotude

Oxygen and nitrogen adsorption in single walled carbon nanotube (SWCNT) is studied by density function and discrete variational (DFT-DVM) method.The models of O 2 and N 2 adsorption in the SWCNT are optimized based on the energy minimization.The calculated results of density of state,populations and energy gaps of the molecular orbitals show that oxygen adsorption in SWCNT increases the carbon nanotube`s electrical conductivity more notably than nitrogen adsorption,which is consistent with the experiment.

Highly-efficient separation of pyromellitic acid and trimellitic acid mixtures via forming deep eutectic solvents:Experiment and calculation

Pyromellitic acid(PMA)and trimellitic acid(TMA)are significant chemical raw materials and intermediates.They simultaneously exist in the industry processes of synthesis and are difficult to be separated.In this work,several kinds of biodegradable compounds were chosen as hydrogen bond acceptors(HBAs)to separate PMA and TMA mixtures from acetone solutions via forming deep eutectic solvent(DES).It has been found that all these compounds can separate PMA and TMA mixtures to obtain pure PMA or TMA.However,the interaction between HBAs and PMA or TMA is quite different.Choline chloride cannot extract TMA but can form a DES with PMA in acetone.Hexamethylenetetramine(HA)and L-carnitine(L-car)can form DESs with both PMA and TMA in acetone solution.But when L-car or HA is added,the extraction rate of PMA is larger than that of TMA until the extraction rate of PMA reach 100%,and pure TMA is left in the acetone solution.The selective separation mechanism was explored by infrared spectroscopy combined with quantum chemistry calculation,and the strength and site of the interaction between extractants with PMA and TMA were calculated.

Quantum chemical calculations on structure of Mo_(8)O_(26)^(4-)

Two possible structures of Mo 8O 4- 26 were optimized using the Polak-Ribiere method of Molecular Mechanics Optimization and the termination condition is RMS (Root-mean-square) gradient of 0.42 kJ/mol. Based on the calculations of the molecular dynamics, Lengevin dynamics and Monte Carlo dynamics simulation, the structure models of Mo 8O 4- 26 with the lowest energy were acquired respectively according to the energy of the systems calculated using the ZIDO/1 and PM3 methods. The total energy, energies of some frontier molecular orbitals and atomic charges of Mo 8O 4- 26 were computed at the HF/3-21G and HF/STO-3G levels. The calculation results show that the contortion of the structure with eight MoO 6 is smaller than that of the structure with six MoO 6 and two MoO 4. The total energies of the two structures are nearly equal because the contortion of the structure with six MoO 6 and two MoO 4 would make the exclusion force decreased.

Charge effects on quinoline hydrodenitrogenation catalyzed by Ni-Mo-S active sites-A theoretical study by DFT calculation

The charge distribution on Ni-Mo-S active sites can affect hydrodenitrogenation(HDN)activity.In this study,a series of model Ni-Mo-S were developed with various charge distributions.For comparison,the charge distribution effects on quinoline HDN were studied.The results show that a lack of electrons and extra protons can both lower the orbital eigenvalue of the Ni-Mo-S,leading to stronger adsorption of nitrogen-containing compounds and inhibition of ammonia desorption.Electron deficiency will improve the generation of active hydrogen on the active sites but inhibit hydrogen transfer to the nitrogen compounds;extra protons can provide H^(+)to the nitrogen compounds,which will flexibly transfer between the nitrogen compound and active sites,thus improving the cleavage of the C-N bond.

Effects of the structural order of canthaxanthin on the Raman scattering cross section in various solvents:A study by Raman spectroscopy and ab initio calculation

In this work,we measure the Raman scattering cross sections（RSCSs） of the carbon-carbon（CC） stretching vibrational modes of canthaxanthin in benzene,acetone,n-heptane,cyclohexane,and m-xylene.It is found that the absolute RSCS of CC stretching mode of canthaxanthin reaches a value of 10 24 cm ^-2 ·molecule ^-1 ·sr ^-1 at 8×10 ^-5 M,which is 6 orders of magnitude larger than general RSCS（10 30 cm 2 ·molecule 1 ·sr 1）,and the RSCSs of canthaxanthin in various solvents are very different due to the hydrogen bond.A theoretical interpretation of the magnetic experimental results is given,which is introduced in a qualitative nonlinear model of coherent weakly damped electron-lattice vibration in the structural order of polyene chains.In addition,the optimal structure and the bond length alternation（BLA） parameter of canthaxanthin are calculated using quantum chemistry calculation（at the b3lyp/6-31g（d,p） level of theory）.The theoretical calculations are in good agreement with the experimental results.Furthermore,the combination of Raman spectroscopy and the quantum chemistry calculation study would be a quite suitable method of studying the structures and the properties of the π-conjugated systems.

Synthesis,Crystal Structure and Theoretical Calculation of 1,1',5,5'-Tetramethyl-2,2'-diphenyl-4,4'-[i-phenylene-bis(methylidy-nenitrilo)]di-1H-pyrazol-3(2H)-one

1,1＇,5,5＇-Tetramethyl-2,2＇-diphenyl-4,4＇-[i-phenylenebis（methylidynenitrilo）]di-1H-pyrazol-3（2H）-one was synthesized and characterized by X-ray single-crystal diffraction analysis.The crystal crystallizes in monoclinic,space group P21/c with a = 6.1375（1）,b = 24.6571（4）,c = 17.7487（3） ,β = 94.781（1）°,V = 2676.62（8） 3,C30H28N6O2,Mr = 504.58,Z = 4,Dc = 1.252 g/cm3,F（000） = 1064,μ = 0.081 mm-1,R = 0.0463 and wR = 0.1153（I 〉2σ（I））.Theoretical studies of the title compound were carried out by density functional theory（DFT） BLYP method,using ADF program package.It indicates that N（26） and N（41） are active sites of the title compound.

Quantum Chemistry Studies on the Free-radical Growth Mechanism of Polycyclic Arenes from Benzene Precursors

The free-radical growth mechanisms for the formation of polycyclic arenes (PCAs) were constructed based on the block unit of benzene, and were calculated by the quantum chemistry PM3 method. Two kinds of reaction paths are proposed and discussed. The calculation results show that the formation of PCAs is only controlled by the elimination of H atom from benzene, and the corresponding activation energy is 307.60 kJ·mol-1. H2 is only the ef-fluent gas in our proposed reaction mechanism, and the calculation results are in accord with the experimental facts.

QUANTUM CHEMISTRY ON FLOTATION BEHAVIOR OF KYANITE－GROUP POLYMERPHOUS MINERALS

ＱＵＡＮＴＵＭＣＨＥＭＩＳＴＲＹＯＮＦＬＯＴＡＴＩＯＮＢＥＨＡＶＩＯＲＯＦＫＹＡＮＩＴＥ－ＧＲＯＵＰＰＯＬＹＭＥＲＰＨＯＵＳＭＩＮＥＲＡＬＳ￥Ｄｏｎｇ，Ｈｏｎｇｊｕｎ；Ｃｈｅｎ，Ｊｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭｉｎｅｒａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｃ...

Structural and Bonding Properties of Al_(n)C_(4)^(−/0)(n=2−4)Clusters:Anion Photoelectron Spectroscopy and Theoretical Calculations

We measured the photoelectron spectra of Al_(n)C_(4)^(−)(n=2−4)clusters by using size-selected anion photoelectron spectroscopy.The structures of Al_(n)C_(4)^(−/0)(n=2−4)clusters were explored with quantum chemistry calculations and were determined by comparing the theoretical results with the experimental spectra.It is found that the most stable structure of Al_(2)C_(4)^(−) anion is a C_(2v)symmetry planar structure with two Al atoms interacting with two C_(2)units.In addition,Al_(2)C_(4)^(−) anion also has a D∞h symmetry linear structure with two Al atoms located at the two ends of a C_(4)chain,which is slightly higher in energy than the planar structure.The most stable structure of neutral Al_(2)C_(4)has a D∞h symmetry linear structure.The most stable structure of Al_(3)C_(4)^(−) anion is a planar structure with three Al atoms interacting with two C_(2)units.Whereas neutral Al_(3)C_(4)cluster has a C_(2v)symmetric V-shaped bent structure.The global minima structures of both Al_(4)C_(4)^(−) and neutral Al_(4)C_(4)are C_(2)h symmetry planar structures with four Al atoms interacting with the ends of two C_(2)units.Adaptive natural density partitioning analyses of Al_(n)C_(4)^(−)(n=2−4)clusters show that the interactions between the Al atoms and C_(2)units have bothσandπcharacters.

Calculating the dielectric anisotropy of nematic liquid crystals:a reinvestigation of the Maier-Meier theory

This paper investigates the average dielectric permittivity （^-ε） in the Maier-Meier theory for calculating the dielectric anisotropy （△ε） of nematic liquid crystals.For the reason that ^-ε of nematics has the same expression as the dielectric permittivity of the isotropic state,the Onsager equation for isotropic dielectric was used to calculate it.The computed ^-ε shows reasonable agreement with the results of the numerical methods used in the literature.Molecular parameters,such as the polarizability and its anisotropy,the dipole moment and its angle with the molecular long axis,were taken from semi-empirical quantum chemistry （MOCPAC/AM1） modeling.The calculated values of △ε according to the Maier-Meier equation are in good agreement with the experimental results for the investigated compounds having different core structures and polar substituents.

氨燃烧过程中H_(2)NO中间体演化对氮氧化物NO_(x)生成的影响

氨(NH_3)是一种无碳富氢的燃料,可以实现燃烧过程中零碳排放。然而,氨中含有的N可能会被氧化生成氮氧污染物(NO_(x)),造成大气环境污染。为此,基于量子化学计算,该文从微观层面研究氨燃料燃烧过程中H_2NO中间体的演化过程,并分析其对NO_(x)生成的影响。理论计算结果表明,H_(2)NO是NO生成的重要中间体,通过氮氧化物分解基元反应生成NO,其活化能为93.53 kJ/mol;而H_(2)NO的脱氢产物HNO则是NO_(2)生成的关键中间体,通过氮氧化物氧化基元反应促成NO_(2)的生成,其活化能为43.73 kJ/mol。从量子化学角度来看,在氨燃烧过程中高温条件均使NO和NO_(2)生成反应的活化能和吉布斯自由能变不同程度地升高,而高压条件对其几乎没有产生影响。该研究可为降低氨燃烧过程中NO_(x)生成提供一定理论参考。

双重动态交联vitrimer树脂中电树枝劣化及局部放电与降解回收特性

构建动态可逆交联网络是实现树脂类电工材料环保化的重要手段。该文基于动态交换反应理论,在传统环氧/酸酐树脂体系中引入酯交换促进剂三乙醇胺和动态二硫键,制备具有双重动态交联的类玻璃化环氧树脂(vitrimer),并采用针板电极模型研究不同二硫键含量下该树脂体系的电树枝引发与生长及局部放电特性,利用分形维数定量描述不同树脂体系中电树枝形态特征,利用表面电位衰减测试和交联结构的量子化学计算分析不同二硫键含量的vitrimer陷阱特性和电子轨道分布特征。结果表明:随着树脂体系中二硫键的增多,树脂陷阱能级提高,电子轨道能级减小,树脂电树引发电压略有降低,电树生长速度加快且电树形态分形维数降低。最后,通过模拟绕组浇注器件降解回收实验研究树脂动态交换与降解特性。研究发现,双重动态交联网络赋予树脂优异的动态特性,实现内部高价值材料的高效无损回收,可为电工材料的环保化及退役设备的回收处理提供新的思路和选择。