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Ab initio Study of Complexation Process between Poly(amido-amine) and Nano-Silicon Dioxide 被引量:3
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作者 靳涛 吕海亮 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第3期277-286,I0003,共11页
To understand better the molecular-level details of ≡Si+ (SC) or ≡SiO- (SOA) ion group to -NH2 teminated poly(amido-amine) dendrimers in the gas phase, density functional theory is used to optimize the minimu... To understand better the molecular-level details of ≡Si+ (SC) or ≡SiO- (SOA) ion group to -NH2 teminated poly(amido-amine) dendrimers in the gas phase, density functional theory is used to optimize the minimum energy and transition state structures with UB3LYP/6- 311G(d) and HF/6-31G levels. The tertiary amine nitrogen and the amide oxygen are found to be the most favorable binding sites. The activation energies of the different active sites and the reaction steps of SC and/or SOA ion group and the amide sites are also analyzed. The stable compounds are formed via the electrostatic interaction and the coordination effect. The orientation of the amide O and the rotation of the branches minimizes the energy of the whole system. 展开更多
关键词 POLYAMIDOAMINE Activation energy Transition state Density functionaltheory
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High Pressure Phase Stability of Ti with Self-consistent ab initio Lattice Dynamics Approach
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作者 曾召益 胡翠娥 +2 位作者 刘勋 张伟 蔡灵仓 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第2期168-172,I0001,共6页
The traditional quasiharmonic approximation cannot predict the phase diagram of Ti accu- rately, due to the well-known soften phonon modes of the β-Ti. By means of self-consistent ab initio lattice dynamics (SCAILD... The traditional quasiharmonic approximation cannot predict the phase diagram of Ti accu- rately, due to the well-known soften phonon modes of the β-Ti. By means of self-consistent ab initio lattice dynamics (SCAILD) method, in which the effects of phonon-phonon in- teractions are considered, the phonon dispersion relations at finite temperature for Ti are calculated. From the phonon dispersions, we extrapolat the acoustic velocities and harmonic elastic constants. The dynamical stable regions and phase diagram of Ti are also predicted successfully. The results show that SCAILD method can be designed to work for strongly anharmonic systems where the QHA fails. 展开更多
关键词 Transition metal Lattice dynmnics Phase transition Density functionaltheory
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Vibrational Spectra and Density Functional Theory Calculations of Metallotriphenylcorroles
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作者 高慧玲 陈方 +2 位作者 王春雷 王国兵 陈东明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第4期398-408,J0001,共12页
The infrared absorption and Raman scattering spectra were measured for the metallotriph- enylcorroles (MTPCs, M=Cu, Co, Ni, Mn). The ground-state structures and vibrational spectra of MTPCs have been calculated with... The infrared absorption and Raman scattering spectra were measured for the metallotriph- enylcorroles (MTPCs, M=Cu, Co, Ni, Mn). The ground-state structures and vibrational spectra of MTPCs have been calculated with the density functional theory. The observed Raman and IR bands have been assigned based on the calculation results. Due to the symmetry lowering, the vibrational spectra of MTPCs are much more complex than metal- loporphyrins, and several skeletal modes are found strongly coupled to the phenyl vibrations. The relationship between the Raman/IR frequencies and the structures of TPC ring is in-vestigated. It is found that the vibrations involving the Cα^I Cα^I stretch and CαCm stretchare sensitive to the size of corrole core. In particular, the frequency of v5, which is assigned to Cα^I Cα^I stretch in coupling with the CαCm symmetric stretch, increases linearly with the decrease of the corrole core-sizes and may be used as a mark band to evaluate the structural change of the metallocorroles. 展开更多
关键词 Metallocorroles Raman spectrum Molecular vibration Density functionaltheory
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Theoretical Study on Optical Properties of Oligofluorenes
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作者 宋建 刘玉芳 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第4期409-414,J0001,共7页
We present theoretical investigations on structure-property correlations in fluorenone (FLO) and benzothiadiazole (BT) substituted oligofluorenes (OFLs) derived mainly from the chain morphology, thermal vibratio... We present theoretical investigations on structure-property correlations in fluorenone (FLO) and benzothiadiazole (BT) substituted oligofluorenes (OFLs) derived mainly from the chain morphology, thermal vibration and conjugated extent. Both the vertical absorptions and the vibrationally-resolved absorption and fluorescence spectra have been calculated by the com- bination of ab initio and time-dependent density functional theory. By properly taking into account of the anharmonic torsion potentials in the OFLs, we have reasonably reproduced the experimentally observed spectroscopic features. Both FLO and BT on-chain chemical defects acting as charge-trapping sites for singlet excitations, are responsible for long wave absorption and emission species, and thus alter the blue light-emitting properties of OFLs. As temperature decreases, the electronic spectral lineshapes of FLO-substituted oligomers become more structured. The lineshapes of BT-substituted oligomers are always smooth and featureless because of less low collective modes resonance. A more gentle excited poten-tial energy surface of BT-mixed molecules can enhance electronic delocalization and achieve bigger red shifts. 展开更多
关键词 Oligofluorene Electronic spectroscopy Time-dependent density functionaltheory Vibrationlly-resolved
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Adsorption of NO and NH_3 over CuO/γ-Al_2O_3 catalyst 被引量:2
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作者 赵清森 孙路石 +3 位作者 刘勇 苏胜 向军 胡松 《Journal of Central South University》 SCIE EI CAS 2011年第6期1883-1890,共8页
The selective catalytic reduction reaction belongs to the gas-solid multiphase reaction, and the adsorption of NH3 and NO on CuO/γ-Al2O3 catalysts plays an important role in the reaction. Performance of the CuO/γ-Al... The selective catalytic reduction reaction belongs to the gas-solid multiphase reaction, and the adsorption of NH3 and NO on CuO/γ-Al2O3 catalysts plays an important role in the reaction. Performance of the CuO/γ-Al2O3 catalysts was explored in a fixed bed adsorption system. The catalysts maintain nearly 100% NO conversion efficiency at 350℃. Comprehensive tests were carried out to study the adsorption behavior of NH3 and NO over the catalysts. The desorption experiments prove that NH3 and NO are adsorbed on CuO/γ-Al2O3 catalysts. The adsorption behaviors of NH3 and NO were also studied with the in-situ diffusion reflectance infrared Fourier transform spectroscopy methods. The results show that NH3 could be strongly adsorbed on the catalysts, resulting in coordinated NH3 and NH4+. NO adsorption leads to the formation of bridging bidentate nitrate, chelating bidentate nitrate, and chelating nitro. The interaction of NH3 and NO molecules with the Cu2+ present on the CAl2O3 (100) surface was investigated by using a periodic density functional theory. The results show that the adsorption of all the molecules on the Cu2+ site is energetically favorable, whereas NO bound is stronger than that of NH3 with the adsorption site, and key information about the structural and energetic properties was also addressed. 展开更多
关键词 CUO/Γ-AL2O3 NH3 NO ADSORPTION diffusion reflectance infrared Fourier transform spectroscopy density functionaltheory
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Interaction Mechanism of Nano-silicon Dioxide Modified by Poly(amidoamine) Dendrimers 被引量:1
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作者 Tao Jin Xiao-yu Li 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第5期592-604,I0004,共14页
To gain insight into the attachment of =Si^+ (SC) ion (regarded as guest) to the lowest generation, NH2-terminated poly(amidoamine) (PAMAM) dendrimers (regarded as host) in the liquid phase, density functio... To gain insight into the attachment of =Si^+ (SC) ion (regarded as guest) to the lowest generation, NH2-terminated poly(amidoamine) (PAMAM) dendrimers (regarded as host) in the liquid phase, density functional theory is used to investigate the structures and energetics of the host-guest complex. The effect of solvent on the structures and energetics is also investigated. Various initial configurations of the ion bound to PAMAM are tested, and two stable conformers are found, i.e, types A (=Si^+ is bound to the amine site) and C (=Si^+ is bound to the amide site). Types A and C are the most stable due to the chemical bond formations of Si-N° (amine nitrogen atoms) and Si-O, respectively. The IR spectra for the lowest energy conformers are thoroughly analyzed and compared with the available experimental data. 展开更多
关键词 Poly(amidoamine) Nano-silicon dioxide CONFIGURATION Density functionaltheory
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Electronic structure and infrared spectrum of a W_n C^(0,±) (n = 1-6) cluster 被引量:1
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作者 张秀荣 康张李 郭文录 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期204-211,共8页
WnC0'± (n= 1-6) clusters are investigated by using the density functional theory (DFT) at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within th... WnC0'± (n= 1-6) clusters are investigated by using the density functional theory (DFT) at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within the same size, and constituted by substituting a C atom for one W atom in the structures of Wn+1 clusters. The natural bond orbital (NBO) charge analyses indicate that the direction of electron transfer is from the W atom to the 2p orbital of the C atom. In addition, the calculated infrared spectra of the WnC0'± (n= 2-6) clusters manifest that the vibrational frequencies of neutral, anionic and cationic clusters are similar in a range of 80 cm-1-864 cm-1. The high frequency, strong peak modes are found to be an almost stretched deformation of the carbide atom. Finally, the polarizabilities of WnC0'± (n= 1-6) clusters are also discussed. 展开更多
关键词 WnC0'± (n= 1-6) clusters electronic structure infrared spectrum density functionaltheory
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QSAR for Photodegradation Activity of Polycyclic Aromatic Hydrocarbons in Aqueous Systems
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作者 XU Xiang LI Xianguo 《Journal of Ocean University of China》 SCIE CAS 2014年第1期66-72,共7页
The relationship between chemical structures and photodegradation activity of 12 PAHs is studied using DFT and HF methods, and stepwise multiple linear regression analysis method. The equilibrium geometries and vibrat... The relationship between chemical structures and photodegradation activity of 12 PAHs is studied using DFT and HF methods, and stepwise multiple linear regression analysis method. The equilibrium geometries and vibration frequency have been investigated by considering Solvent effects using a selfconsistent reaction field based on the polarizable continuum model. With DFT and HF methods, different quantum chemical structural descriptors are obtained by quantum chemical calculation and the results with DFT method are better for QSAR model. It is concluded that the photodegradation activity is closely related to its molecular structure. In the regression analysis, the main factors affecting photodegradation rate include the energy of the highest occupied orbital EHOMO and the number of six-carbon benzene ring N1, and the QSAR model successfully established is logkb = 6.046 + 54.830EHOMO + 0.272N1. Statistical evaluation of the developed QSAR shows that the relationships are statistically significant and the model has good predictive ability. EHOMO is the most important factor influcing the photodegradation of PAHs, because the higher EHOMO is, the more easily electron will be excited and the more easily molecular will be degraded. Comparison of the photodegradation of PAHs with their biodegradation shows that the committed step of biodegradation is that the effects of microorganisms make the chemical bond break, while in the committed step of photodegradation PAHs eject electrons. 展开更多
关键词 quantitative STRUCTURE-ACTIVITY relationship (QSAR) POLYCYCLIC AROMATIC hydrocarbons (PAHs) density functionaltheory (DFT) PHOTODEGRADATION
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Direct carboxylation of thiophene with CO_(2) in the solvent-free carboxylate-carbonate molten medium:Experimental and mechanistic insights
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作者 Qingjun Zhang Pengyuan Shi +2 位作者 Xigang Yuan Youguang Ma Aiwu Zeng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第10期264-282,共19页
A feasible synthesis route is devised for realizing direct carboxylation of thiophene and CO_(2) in a relatively mild solvent-free carboxylate-assisted carbonate(semi)molten medium.The effects of reaction factors on p... A feasible synthesis route is devised for realizing direct carboxylation of thiophene and CO_(2) in a relatively mild solvent-free carboxylate-assisted carbonate(semi)molten medium.The effects of reaction factors on product yield are investigated,and the phase behavior analysis of the reaction medium is detected through the thermal characterization techniques.Product yield varies with the alternative carboxylate co-salts,which is attributed to the difference in deprotonation capacity caused by the base effect within the system.Besides,the detailed mechanism of this carbonate-promoted carboxylation reaction is studied,including two consecutive steps of the formation of carbanion through breaking the C-H bond(s)via the carbonate and the nucleophile attacking the weak electrophile CO_(2) to form C-C bond(s).The activation energy barrier in C-H activation step is higher than the following CO_(2) insertion step whether for the formation of the mono-and/or di-carboxylate,which is in good agreement with that of kinetic isotope effect(KIE)experiments,indicating that the C-H deprotonation is slow and the forming presumed carbanion reacts rapidly with CO_(2).Both the activation energy barriers in deprotonation steps are the minimal for the cesium cluster system since there have the weak the cesium Cs-heteroatom S(thiophene)and Cs-the broken proton interactions compared to the K2CO3 system,which is likely to enhance the acidity of C-H bond,lowering the C-H activation barrier.Besides,these mechanistic insights are further assessed by investigating base and C-H substrate effects via replacing Cs2CO3 with K2CO3 and furoate(la)with thiophene monocarboxylate(1b)or benzoate(1c). 展开更多
关键词 Inert CAH bond CARBOXYLATION Solvent-free medium Base effect Density functionaltheory(DFT)study
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Analytical Bond-order Potential for hcp-Y
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作者 Kai-min Fan Li Yang +5 位作者 Jing Tang Qing-qiang Sun Yun-ya Dai Shu-ming Peng Xiao-song Zhou Xiao--tao ZU 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第5期526-532,I0003,共8页
The lattice parameters, elastic constants, cohesive energy, structural energy differences, as well as the properties of point defects and planar defects of hexagonal closepacked yttrium (hcpY) have been studied with... The lattice parameters, elastic constants, cohesive energy, structural energy differences, as well as the properties of point defects and planar defects of hexagonal closepacked yttrium (hcpY) have been studied with ab initio density functional theory for constructing an ex tensive database. Based on an analytical bondorder poial scheme, empirical manybody interatomic potential for hcpY has been developed. The model is fitted to some properties of Y, e.g., the lattice parameters, elastic constants, bulk modulus, cohesive energy, vacancy formation energy, and the structural energy differences. The present potential has ability to reproduce defect properties including the selfinterstitial atoms formation energies, vacancy formation energy, divacancy binding energy, as well as the bulk properties and the thermal dynamic properties. 展开更多
关键词 Hexagonal close-packed yttrium Bond-order potential Density functionaltheory Molecular dynamics
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Adsorption and Decomposition of NH3 on Ni/Pt(111) and Ni/WC(001) Surfaces: A First-Principles Study
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作者 Ai-ai Shen Yi-lin Cao 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第6期710-716,I0002,共8页
Density functional theory was used to study the NH3 behavior on Ni monolayer covered Pt(111) and WC(001). The electronic structure of the surfaces, and the adsorption and decomposition of NH3 were calculated and c... Density functional theory was used to study the NH3 behavior on Ni monolayer covered Pt(111) and WC(001). The electronic structure of the surfaces, and the adsorption and decomposition of NH3 were calculated and compared. Ni atoms in the monolayer behave different from that in Ni(111). More dz2 electrons of Ni in monolayer covered systems were shifted to other regions compared to Ni(111), charge density depletion on this orbital is crucial to NH3 adsorption. NH3 binds more stable on Ni/Pt(lll) and Ni/WC(001) than on Ni(111), the energy barriers of the first N-H bond scission were evidently lower on Ni/Pt(111) and Ni/WC(001) than on Ni(111), these are significant to NH3 decomposition. N recombination is the rate-limiting step, high reaction barrier implies that N2 is produced only at high temperatures. Although WC has similar properties to Pt, differences of the electronic structure and catalytic activities are observed for Ni/Pt(111) and Ni/WC (001), the energy barrier for the rate-determined step increases on Ni/WC(001) instead of decreasing on Ni/Pt(lll) when compared to Ni(111). the N recombination barrier by modifying To design cheaper and better catalysts, reducing Ni/WC(001) is a critical question to be solved. 展开更多
关键词 Ni monolayer Electronic structure NH3 decomposition Density functionaltheory
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Template-directed assembly of pentacene molecules on epitaxial graphene on Ru(0001) 被引量:4
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作者 Haitao Zhou Lizhi Zhang +6 位作者 Jinhai Mao Geng Li Yi Zhang Yeliang Wang Shixuan Du Werner A. Hofer Hong-Jun Gao 《Nano Research》 SCIE EI CAS CSCD 2013年第2期131-137,共7页
The template-directed assembly of planar pentacene molecules on epitaxial graphene grown on Ru(0001) (G/Ru) has been investigated by means of low-temperature scanning tunneling microscopy (STM) and density funct... The template-directed assembly of planar pentacene molecules on epitaxial graphene grown on Ru(0001) (G/Ru) has been investigated by means of low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. STM experiments find that pentacene adopts a highly selective and dispersed growth mode in the initial stage. By using DFT calculations including van der Waals interactions, we find that the configuration with pentacene adsorbed on face-centered cubic (fcc) regions of G/Ru is the most stable one, which accounts for the selective adsorption at low coverage. Moreover, at high coverage, we have successfully controlled the molecular assembly from amorphous, local ordering, to long-range order by optimizing the deposition rate and substrate temperature. 展开更多
关键词 graphene Ru(0001) PENTACENE SELF-ASSEMBLY scanning tunnelingmicroscopy (STM) density functionaltheory (DFT)
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Electronic and magnetic properties of Cd-doped zigzag AlN nanoribbons from first principles 被引量:1
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作者 Razieh Beiranvand 《Rare Metals》 SCIE EI CAS CSCD 2016年第10期771-778,共8页
The effect of Cd impurity on the electronic structure and magnetic properties of hydrogen-terminated AlN nanoribbons with zigzag edges (ZAINNRs) was in- vestigate using the band structure results obtained through th... The effect of Cd impurity on the electronic structure and magnetic properties of hydrogen-terminated AlN nanoribbons with zigzag edges (ZAINNRs) was in- vestigate using the band structure results obtained through the full potential linearized augmented plane wave (FP- LAPW) method within the density functional theory (DFT). The exchange correlation potential was treated by the generalized gradient approximation within the Perdew scheme. The calculated results show that the H-terminated zigzag AlN nanoribbon is semiconducting and nonmag- netic material with a direct band gap of about 2.78 eV, while the Cd-doped H-terminated ZAlNNR structures show complete (100 %) spin polarization very close to the Fermi level, which will result in spin-anisotropic transport. The charge transport is totally dominated by Cd spin down electrons in the H-terminated ZAlNNR. These results suggest potential applications for the development of using the A1N nanoribbons in nanoelectronics and magnetoelec-tronic devices as a base. 展开更多
关键词 Electronic properties Zigzag AlN nanoribbon Magnetic properties Density functionaltheory Full potential linearized augmented plane wave
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Structural phase transition and electronic structure evolution in Ir_(1-x)Pt_xTe_2 studied by scanning tunneling microscopy
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作者 阮威 汤沛哲 +6 位作者 房爱芳 蔡鹏 叶存 李昕彤 段文晖 王楠林 王亚愚 《Science Bulletin》 SCIE EI CAS CSCD 2015年第8期798-805,M0004,共9页
The IrTe2 transition metal dichalcogenide un- dergoes a series of structural and electronic phase transi- tions when doped with Pt. The nature of each phase and the mechanism of the phase transitions have attracted mu... The IrTe2 transition metal dichalcogenide un- dergoes a series of structural and electronic phase transi- tions when doped with Pt. The nature of each phase and the mechanism of the phase transitions have attracted much attention. In this paper, we report scanning tunneling mi- croscopy and spectroscopy studies of Pt-doped IrTe2 with varied Pt contents. In pure IrTe2, we find that the ground state has a 1/6 superstructure, and the electronic structure is inconsistent with Fermi surface nesting-induced charge density wave order. Upon Pt doping, the crystal structure changes to a 1/5 superstructure and then to a quasi-periodic hexagonal phase. First-principles calculations show that the superstructures and electronic structures are determined by the global chemical strain and local impurity states that can be tuned systematically by Pt doping. 展开更多
关键词 IrTe2 Transition metal dichalcogenide Scanning tunneling microscopy Density functionaltheory Charge density wave
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Molecular Structure, Vibrational Spectrum and Ionization Energy of m-Dimethoxybenzene
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作者 黄健涵 黄可龙 +1 位作者 刘素琴 罗琼 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2007年第9期1238-1241,共4页
The optimized molecular geometries of the three rotamers of m-dimethoxybenzene in the ground So and electronically excited Sl states were predicted by ab initio and density functional theory (DFF) calculations. Thei... The optimized molecular geometries of the three rotamers of m-dimethoxybenzene in the ground So and electronically excited Sl states were predicted by ab initio and density functional theory (DFF) calculations. Their vibrational spectra in the St state were studied by one color resonant two photon ionization (1C-R2PI) method, and their ionization energies were measured by two color resonant two photon ionization (2C-R2PI) experiment. The optimized molecular geometries showed that the total energy of conformer a was the lowest in the So state. Most of the active vibrations assigned from the 1C-R2PI spectrum were found to be of the in-plane ring modes. The ionization energies (IE) of conformers a, b and c were determined to be 63521, 64487 and 63755 cm^-1, respectively. 展开更多
关键词 resonant two photon ionization vibrational spectrum ionization energy ab initio density functionaltheory
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Syntheses, Electrochemical Behaviors, Spectral Properties and DFT Calculations of Two 1,3-Dithiole Derivatives
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作者 NIU Zhigang LI Dachao +4 位作者 LIU Dong XIA Dong ZOU Ying SUN Wei LI Gaonan 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2014年第3期425-430,共6页
Two new 1,3-dithiole derivatives, 4,4'-{9-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-9H-fluorene-2,7- diyl} dipyridine(2a) and 3,3'-{9-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-9H-fluorene-2,7-diyl} dipyrid... Two new 1,3-dithiole derivatives, 4,4'-{9-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-9H-fluorene-2,7- diyl} dipyridine(2a) and 3,3'-{9-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-9H-fluorene-2,7-diyl} dipyridine(2b) were synthesized and characterized by Fourier transform infrared(FTIR), 1H NMR, 13C NMR and mass spectroscopies. The crystal structure of compound 2b was also studied. The optimized conformations and molecular orbital diagrams of compounds 2a and 2b were illustrated via density functional theory(DFT). By the time-dependent DFT(TD-DFT) method, electronic absorption spectra of compounds 2a and 2b were predicted and the results achieved were in good agreement with the experimental data. The formation of the cationic radical during the electrochemical oxidation process was also proposed. 展开更多
关键词 1 3-Dithiole derivative PYRIDINE X-Ray diffraction Linear sweep voltammetry Density functionaltheory(DFT) calculation
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