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Investigation of Highly Designable Dented Structures in HP Model with Hydrogen Bond Energy
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作者 ZHANG Wei HUANG Shengyou YU Tao ZOU Xianwu 《Wuhan University Journal of Natural Sciences》 CAS 2007年第6期1034-1038,共5页
Some highly designable protein structures have dented on the surface of their native structures, and are not full compactly folded. According to hydrophobic-polar (HP) model the most designable structures are full c... Some highly designable protein structures have dented on the surface of their native structures, and are not full compactly folded. According to hydrophobic-polar (HP) model the most designable structures are full compactly folded. To investigate the designability of the dented structures, we introduce the hydrogen bond energy in the secondary structures by using the secondary-structure-favored HP model proposed by Ou-yang etc. The result shows that the average designability increases with the strength of the hydrogen bond. The designabilities of the structures with same dented shape increase exponentially with the number of secondary structure sites. The dented structures can have the highest designabilities for a certain value of hydrogen bond energy density. 展开更多
关键词 protein folding DESIGNABILITY dented structure hydrogen bond energy HP model
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Average Bond Energy and Fermi Level on Free Electronic Band Model
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作者 ZHENGYongmei WANGRenzhi 《Semiconductor Photonics and Technology》 CAS 1999年第1期9-13,共5页
On the basis of free-electronic bands, the Fermi energy is calculated by summing the band eigenvalues over Brillouin-zones ,and the results may lead to understand the physical basis of the average-bond-energy model in... On the basis of free-electronic bands, the Fermi energy is calculated by summing the band eigenvalues over Brillouin-zones ,and the results may lead to understand the physical basis of the average-bond-energy model in the calculation of valence-band offsets. 展开更多
关键词 Average bond energy Fermi Level HETEROJUNCTION
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A neural network protocol for predicting molecular bond energy 被引量:5
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作者 Chao Feng Edward Sharman +2 位作者 Sheng Ye Yi Luo Jun Jiang 《Science China Chemistry》 SCIE EI CAS CSCD 2019年第12期1698-1703,共6页
Molecular bond energy is a key parameter for analyzing the properties of chemical activity,stability and flexibility.Calculating bond energy is a challenge due to the cost of first-principles simulations and unsatisfa... Molecular bond energy is a key parameter for analyzing the properties of chemical activity,stability and flexibility.Calculating bond energy is a challenge due to the cost of first-principles simulations and unsatisfactory prediction using empirical formula.Here we show that a neural network(NN)machine-learning method can achieve quick prediction of bond energies of organic molecules.Using atomic species and charge information as descriptors,we trained a NN protocol and applied it to predict the bond energy in a certain chemical bond that agreed with density functional theory calculations.This protocol also provided a way to evaluate the effects of different methods of atomic charge analysis on NN training.Trained to accurately estimate bond energies,this NN protocol provides a cost-effective tool for optimizing chemical reactions,accelerating molecular design,and other important applications. 展开更多
关键词 bond energy neural network density functional theory
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Bonding Energy of a Molecular Orbital(Ⅱ)——Ab initio Calculation
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作者 YANG Zhong-zhi and SHEN Er-zhong (Institute of Theoretical Chemistry, Jilin University, Changchun, 130023) 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1992年第2期96-98,共3页
Calculation of the bonding energy of a molecular orbital for a series of small molecules has been carried out by using ab initio STO-3G method. The results obtained demonstrate that the concept of the molecular orbita... Calculation of the bonding energy of a molecular orbital for a series of small molecules has been carried out by using ab initio STO-3G method. The results obtained demonstrate that the concept of the molecular orbital bonding energy is applicable for judging whether a molecular orbital is bonding, nonbonding or antibonding besides Mulliken overlap criterion. 展开更多
关键词 Molecular orbital bonding energy Ab initio STO-3G
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Prediction of Bond Dissociation Energy for Organic Molecules Based on a Machine-Learning Approach
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作者 Yidi Liu Yao Li +3 位作者 Qi Yang Jin-Dong Yang Long Zhang Sanzhong Luo 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2024年第17期1967-1974,共8页
Bond dissociation energy(BDE),which refers to the enthalpy change for the homolysis of a specific covalent bond,is one of the basic thermodynamic properties of molecules.It is very important for understanding chemical... Bond dissociation energy(BDE),which refers to the enthalpy change for the homolysis of a specific covalent bond,is one of the basic thermodynamic properties of molecules.It is very important for understanding chemical reactivities,chemical properties and chemical transformations.Here,a machine learning-based comprehensive BDE prediction model was established based on the iBonD experimental BDE dataset and the calculated BDE dataset by St.John et al.Differential Structural and PhysicOChemical(D-SPOC)descriptors that reflected changes in molecules'structural and physicochemical features in the process of bond homolysis were designed as input features. 展开更多
关键词 bond dissociation energy Machine learning Molecular descriptors PREDICTION
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THE CALCULATION OF THE COHESIVE ENERGY OFГPHASE IN THE TRANSITIONAL LAYER FE ZN OF HEAT GALVANIZED SHEET USED IN CARS
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作者 W.M. Ma1) , C.F. Qian2) and X.F. Cheng2) 1) Shenyang University ,Shenyang 110044 ,China 2) Northeastern University ,Shenyang 110006 , China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第4期539-543,共5页
hethesisanalysesthevalenceelectronstructuresof phase Γin Fe Zn transitionallayerof heat galvanized sheet used in cars by applying the Empirical Electron Theory of Solids andMolecules, and calculatesthebond energy o... hethesisanalysesthevalenceelectronstructuresof phase Γin Fe Zn transitionallayerof heat galvanized sheet used in cars by applying the Empirical Electron Theory of Solids andMolecules, and calculatesthebond energy ofthe major bondsand cohesiveenergy ofcrystals,from which we draw theconclusion:sincecrystal has alargercohesiveenergy, it has higherhardness, butsinceitsbondenergyisratherlow ,itiseasytobreak under pressurefrom out side, and thecrackiseasytocome up andspreadin phase Γ. 展开更多
关键词 the empirical electron theory of solids and molecules valence electron structures bond energy cohesiveenergy
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Diffusion Monte Carlo Study of Bond Dissociation Energies for BH2, B(OH)2, BCl2, and BCI
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作者 李会然 程新路 张红 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第1期65-69,I0003,I0004,共7页
On basis of bond dissociation energies (BDEs) for BH2, B(OH)2, BCl2, and BCl, the diffusion Monte Carlo (DMC) method is applied to explore the BDEs of HB-H, HOB-OH, ClB-Cl, and B-Cl. The effect of the choice of ... On basis of bond dissociation energies (BDEs) for BH2, B(OH)2, BCl2, and BCl, the diffusion Monte Carlo (DMC) method is applied to explore the BDEs of HB-H, HOB-OH, ClB-Cl, and B-Cl. The effect of the choice of orbitals, as well as the backflow transformation, is studied. The Slater-Jastrow DMC algorithm gives BDEs of 359.1±0.12 kJ/mol for HB-H, 410.5±0.50 kJ/mol for HOB-OH, 357.8±1.46 kJ/mol for ClB-Cl, and 504.5±0.96 kJ/mol for B-Cl using B3PW91 orbitals and similar BDEs when B3LYP orbitals are used. DMC with backflow corrections (BF-DMC) gives a HB-H BDE of 369.9±0.12 kJ/mol which is close to one of the available experimental value (375.8 kJ/mol). In the case of HOB-OH BDE, the BF-DMC calculation is 446.04-1.84 k J/mol that is closer to the experimental BDE. The BF-DMC BDE for ClB-Cl is 343.2±2.34 kJ/mol and the BF-DMC B-Cl BDE is 523.3±0.33 kJ/mol, which are close to the experimental BDEs, 341.9 and 530.0 kJ/mol, respectively. 展开更多
关键词 bond dissociation energy Diffusion Monte Carlo method Choice of orbitals Backflow transformation
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Is HOMO Energy Level a Good Parameter to Characterize Antioxidant Activity 被引量:1
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作者 Hong Yu ZHANG De Zhan CHEN 《Chinese Chemical Letters》 SCIE CAS CSCD 2000年第8期727-730,共4页
Semiempirical quantum chemical method AM1 was employed to calculate the highest occupied molecular orbital (HOMO) energy levels (E-HOMO) for various types of antioxidants. It was verified that the correlation between ... Semiempirical quantum chemical method AM1 was employed to calculate the highest occupied molecular orbital (HOMO) energy levels (E-HOMO) for various types of antioxidants. It was verified that the correlation between logarithm of free radical scavenging rate constants (1gks) and E-HOMO substantially arises from the correlation between E-HOMO and O-H bond dissociation energies (BDE) of antioxidants. Furthermore, E-HOMO were poorly correlated with the logarithm of relative free radical scavenging rate constants (1gk(3)/k(1)) for various types of antioxidants that possess complex structures (r = 0.5602). So in a broad sense, E-HOMO was not an appropriate parameter to characterize the free radical scavenging activity of antioxidants. 展开更多
关键词 AM1 ANTIOXIDANT free radical HOMO energy level O-H bond dissociation energy structure-activity relationship
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The evaluation of bond dissociation energies for NO2 scission in nitro compounds using density functional and complete basis set methods 被引量:1
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作者 邵菊香 程新路 +1 位作者 杨向东 何碧 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第2期329-333,共5页
By using the density functional theory (B3LYP) and four highly accurate complete basis set (CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M)ab initio methods, the X(C, N, O)-NO2 bond dissociation energies (BDEs) for CH3NO2... By using the density functional theory (B3LYP) and four highly accurate complete basis set (CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M)ab initio methods, the X(C, N, O)-NO2 bond dissociation energies (BDEs) for CH3NO2, C2H3NO2, C2H5NO2, HONO2, CH3ONO2, C2H5ONO2, NH2NO2 (CH3)2NNO2 are computed. By comparing the computed BDEs and experimental results, it is found that the B3LYP method is unable to predict satisfactorily the results of bond dissociation energy (BDE); however, all four CBS models are generally able to give reliable predication of the X(C, N, O)-NO2 BDEs for these nitro compounds. Moreover, the CBS-4M calculation is the least computationally demanding among the four CBS methods considered, Therefore, we recommend CBS-4M method as a reliable method of computing the BDEs for this nitro compound system. 展开更多
关键词 bond dissociation energy B3LYP CBS models nitro compound
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Quantum chemical calculations of bond dissociation energies for COOH scission and electronic structure in some acids 被引量:1
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作者 曾晖 赵俊 肖循 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期198-203,共6页
Quantum chemical calculations are performed to investigate the equilibrium C-COOH bond distances and the bond dissociation energies(BDEs) for 15 acids.These compounds are studied by utilizing the hybrid density func... Quantum chemical calculations are performed to investigate the equilibrium C-COOH bond distances and the bond dissociation energies(BDEs) for 15 acids.These compounds are studied by utilizing the hybrid density functional theory(DFT)(B3LYP,B3PW91,B3P86,PBE1PBE) and the complete basis set(CBS-Q) method in conjunction with the 6311G^** basis as DFT methods have been found to have low basis sets sensitivity for small and medium molecules in our previous work.Comparisons between the computational results and the experimental values reveal that CBS-Q method,which can produce reasonable BDEs for some systems in our previous work,seems unable to predict accurate BDEs here.However,the B3P86 calculated results accord very well with the experimental values,within an average absolute error of 2.3 kcal/mol.Thus,B3P86 method is suitable for computing the reliable BDEs of C-COOH bond for carboxylic acid compounds.In addition,the energy gaps between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) of studied compounds are estimated,based on which the relative thermal stabilities of the studied acids are also discussed. 展开更多
关键词 bond dissociation energy density functional theory CBS-Q method
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Density Functional Calculations of C–NO_2 Bond Dissociation Energies for Nitroalkanes Molecules 被引量:1
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作者 李小红 张瑞州 +2 位作者 张现周 杨向东 程新路 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第12期1481-1485,共5页
Bond dissociation energies for the removal of nitrogen dioxide group in some nitroalkane energetic materials have been calculated by using the three hybrid density functional theory (DFT) methods B3LYP, B3PW91 and B... Bond dissociation energies for the removal of nitrogen dioxide group in some nitroalkane energetic materials have been calculated by using the three hybrid density functional theory (DFT) methods B3LYP, B3PW91 and B3P86 with 6-31g^** and 6-311g^** basis sets. The computed BDEs have been compared with the available experimental results. It is found that the B3P86 method with 6-31g^** and 6-311g^** basis sets can obtain satisfactory bond dissociation energies (BDEs), which are in extraordinary agreement with the experimental data. Considering the smaller mean absolute deviation and maximum difference, the reliable B3P86/6-311g^** method was recommended to compute the BDEs for the removal of nitrogen dioxide group in the nitroalkane energetic materials. Using the method, the BDEs of 8 other nitroalkane energetic materials have been calculated and the maximum difference from experimental value is 1.76 kcal.mo1^-1 (for the BDE of tC4Hg-NOz), which further proves the reliability of B3P86/6-311g^** method. In addition, it is noted that the BDEs of C-NO2 bond change slightly for main chain nitroalkane compounds with the maximum difference of only 3.43 kcal mo1^-1. 展开更多
关键词 bond dissociation energy density functional calculation nitroalkane energetic compound
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Theoretical Study of the N-NO_2 Bond Dissociation Energies for Energetic Materials with Density Functional Theory 被引量:1
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作者 李小红 汤正新 +2 位作者 Abraham F.Jalbout 张现周 程新路 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第6期677-682,共6页
The N-NO2 bond dissociation energies (BDEs) for 7 energetic materials were computed by means of accurate density functional theory (B3LYP, B3PW91 and B3P86) with 6-31G** and 6-311G** basis sets. By comparing t... The N-NO2 bond dissociation energies (BDEs) for 7 energetic materials were computed by means of accurate density functional theory (B3LYP, B3PW91 and B3P86) with 6-31G** and 6-311G** basis sets. By comparing the computed energies and experimental results, we find that the B3P86/6-311G** method can give good results of BDE, which has the mean absolute deviation of 1.30kcal/mol. In addition, substituent effects were also taken into account. It is noted that the Hammett constants of substituent groups are related to the BDEs of the N-NO2 bond and the bond dissociation energies of the energetic materials studied decrease when increasing the number of NO2 group. 展开更多
关键词 density functional theory bond dissociation energy energetic materials substituent effect
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Research on C—C Bond Length Distribution in Hydrocarbon Molecules 被引量:1
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作者 Liu Jun Long Jun +1 位作者 He Zhenfu Dai Zhenyu (Research Institute of Petroleum Processing,SINOPEC,Beijing 100083) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2010年第3期6-11,共6页
The C--C bond dissociation energy (BDE) is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the ... The C--C bond dissociation energy (BDE) is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the C--C bond dissociation energy (BDE) by experiments, so using quantum chemistry calculation such as density functional theory (DFT) to study the C--C bond dissociation energy is a very useful means. The impact of acceptor substituents and donor substituents on the C--C bond length distribution was studied. 展开更多
关键词 hydrocarbon molecules bond dissociation energy (BDE) density functional theory (DFT) acceptor substituent donor substituent
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Bonding Energies and Structural Study of Alkylaluminium
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作者 ZHAO Yan-Yun CHENG Xue-Li +1 位作者 LI Li-Qing LI Zhen 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第6期833-838,共6页
Neutral aluminium alkyls are well known to act as ethylene oligomerization and polymerization catalysts and cocatalysts.On the basis of the full optimization of alkylaluminium compounds with Gaussian 98 program packag... Neutral aluminium alkyls are well known to act as ethylene oligomerization and polymerization catalysts and cocatalysts.On the basis of the full optimization of alkylaluminium compounds with Gaussian 98 program package at the B3LYP/6-31G** level,the selected structures and bonding energies were investigated extensively.The geometries and bonding energies of AlR3(R = H,CH3,C2H5,C3H7,C4H9) and Al(C2H5)2R'(R' = C2H5,C3H7,C4H9,C5H11,C6H13) were investigated extensively,and we found that,along with the prolongation of carbon chains the terminal C-C bond is shortened gradually until to a constant value of about 0.1532 nm in C4H9;and the bonding energy almost remains constant.The dative bonding of C2H4 to Al(C2H5)3,whose bonding energy is only 15.30 kJ/mol,is very weak. 展开更多
关键词 ALKYLALUMINIUM bonding energy molecular geometry steric effect
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1, 4-Pyrone Effects on O-H Bond Dissociation Energies of Catechols in Flavonoids: A Density Functional Theory Study
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作者 HongYuZHANG YouMinSUN 《Chinese Chemical Letters》 SCIE CAS CSCD 2002年第6期531-534,共4页
关键词 ANTIOXIDANT density functional theory flavonoid O-H bond dissociation energy structure-activity relationships.
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Chemical Empiricism 2.0 at Age of Big Data: Large-scale Prediction of Reaction Pathways Based on Bond Dissociation Energies
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作者 Shi-lu Chen 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第6期-,共7页
关键词 Big data bond dissociation energy Reaction pathway PREDICTION
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Covalent electron density analysis and surface energy calculation of gold with the empirical electron surface model
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作者 Bao-qin Fu Zhi-lin Li Wei Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第6期676-682,共7页
Based on the empirical electron surface model (EESM),the covalent electron density of dangling bonds (CEDDB) was calculated for various crystal planes of gold,and the surface energy was calculated further.Calculat... Based on the empirical electron surface model (EESM),the covalent electron density of dangling bonds (CEDDB) was calculated for various crystal planes of gold,and the surface energy was calculated further.Calculation results show that CEDDB has a great influence on the surface energy of various index surfaces and the anisotropy of the surface.The calculated surface energy is in agreement with experimental and other theoretical values.The calculated surface energy of the close-packed (111) surface has the lowest surface energy,which agrees with the theoretical prediction.Also,it is found that the spatial distribution of covalent bonds has a great influence on the surface energy of various index surfaces.Therefore,CEDDB should be a suitable parameter to describe and quantify the dangling bonds and surface energy of various crystal surfaces. 展开更多
关键词 surface energy dangling bonds covalent bonds electron density gold
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Density Functional Theory Study of Marine Polybrominated Diphenyl Ethers in Anaerobic Degradation
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作者 XU Xiang MAN Miaomiao +3 位作者 SUN Qinxing LIU Qingzhi WU Kechen YANG Dengfeng 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第5期1353-1360,共8页
Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway... Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway of anaerobic degradation.On the basis of experimental study,Octa-BDE 197,Hepta-BDE 183,Hexa-BDE 153,Penta-BDE 99 and Tetra-BDE 47 were selected as the initial degradation objects,and their debromination degradation were studied using density functional theory.The structures were optimized by Gaussian 09 program.Furthermore,the molecular orbitals and charge distribution were analyzed.All C-Br bond dissociation energies at different positions including ortho,meta and para bromine atoms were calculated and the sequence of debromination was obtained.There is a close relationship between molecular structure,charge,molecular orbital and C-Br bond.All PBDEs exhibited similar debromination pathways with preferential removal of meta and para bromines. 展开更多
关键词 polybrominated diphenyl ethers reductive debromination anaerobic degradation density functional theory bond dissociation energies
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Structures and electronic properties of AUn-1Cu and AUn (n ≤ 9) clusters 被引量:2
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作者 王红艳 李喜波 +2 位作者 唐永建 R.Bruce King Henry F.Schaefer III 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第6期1660-1664,共5页
A systematic study on the structure and electronic properties of gold clusters doped each with one copper atom has been performed using the density functional theory. The average bond lengths in the Aun-1Cu (n ≤ 9)... A systematic study on the structure and electronic properties of gold clusters doped each with one copper atom has been performed using the density functional theory. The average bond lengths in the Aun-1Cu (n ≤ 9) bimetallic clusters are shorter than those in the corresponding pure gold clusters. The ionization potentials of the bimetallic clusters Aun-1Cu (n 〈 9) are larger than those of the corresponding homoatomic gold clusters except for Aus. The energy gaps of the Au-Cu binary clusters are narrower than those of the Aun clusters except AuCu and Au3Cu. No obvious even-odd effect exists in the variations of the electron affinities and ionization potentials for the Aun-1Cu (n ≤ 9) clusters, which is in contrast to the case of gold clusters Aun. 展开更多
关键词 Au-Cu bimetallic cluster equilibrium geometry bond energy HOMO-LUMO gap
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Effects of Bases on the Stabilities of Nucleoside C4'Radicals 被引量:1
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作者 Bo Lin LIN, Yao FU, Lei LIU, Qing Xiang GUO Department of Chemistry, University of Science and Technology of China, Hefei 230026 《Chinese Chemical Letters》 SCIE CAS CSCD 2003年第10期1073-1076,共4页
C4'-H bond dissociation enthalpies of nucleosides were predicted using theoretical methods to a precision of 1-2 Kcal/mol. It was found that the stability of the C4' nucleoside radical is slightly dependent on... C4'-H bond dissociation enthalpies of nucleosides were predicted using theoretical methods to a precision of 1-2 Kcal/mol. It was found that the stability of the C4' nucleoside radical is slightly dependent on the base. The orders of stability are dA < dG < dT < dC for deoxynucleosides and U < G < A = C for nucleosides. 展开更多
关键词 NUCLEOSIDE homolysis bond energy DNA lesion substituent effect.
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