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Bonding Energy of a molecular orbital(Ⅱ)——Ab initio Calculation

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Chemical Research in Chinese Universities 1992年第2期8卷 96-98页

作者： YANG Zhong-zhi and SHEN Er-zhong (Institute of Theoretical Chemistry, Jilin University, Changchun, 130023)

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.

关键词： molecular orbital Bonding energy,Ab initio STO-3G

Investigating molecular orbitals with submolecular precision on pristine sites and single atomic vacancies of monolayer h-BN

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Nano Research 2020年第8期13卷 2233-2238页

作者： Liwei Liu Thomas Dienel Gino Günzburger Teng Zhang Zeping Huang Cong Wang Roland Widmer Wei Ji Yeliang Wang Oliver Gröning School of Information and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of TechnologyBeijing100081China Empa Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfCH-8600Switzerland Department of Materials Science and Engineering Cornell University and NSF-MIP Platform for the Accelerated RealizationAnalysisand Discovery of Interface Materials(PARADIM)IthacaNY14853USA Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Renmin University of ChinaBeijing100872China

Understanding the influence of adsorption sites to the electronic properties of adsorbed molecules on two-dimensional(2D)ultrathin insulator is of essential importance for future organic-inorganic hybrid ***,the adsorption and electronic states of manganese phthalocyanine(MnPc)on a single layer of hexagonal boron nitride(h-BN)have been comprehensively studied by low-temperature scanning tunneling microscopy/spectroscopy and tight binding *** frontier orbitals of the MnPc can change drastically by reversible manipulation of individual MnPc molecules onto and away from the single atomic vacancies at the h-BN ***,the change of the molecular electronic configuration can be controlled depending on whether the atomic vacancy is below the metal center or the ligand of the *** findings give new insight into defect-engineering of the organic-inorganic hybrid nanodevices down to submolecular level.

关键词： hexagonal boron nitride phthalocyanine single atomic vacancy molecular orbital scanning tunneling microscopy

Conformation effects on the molecular orbitals of serine

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Chinese Physics B 2011年第3期20卷 143-149页

作者：王克栋马鹏飞单旭 Department of Physics Key Laboratory of Photovoltaic Materials of Henan Province Henan Normal University Department of Modern Physics University of Science and Technology of China

This paper calculates the five most stable conformers of serine with Hartree-Fock theory, density functional theory （B3LYP）, Moller-Plesset perturbation theory （MP4（SDQ）） and electron propagation theory with the 6-311＋＋G（2d,2p） basis set. The calculated vertical ionization energies for the valence molecular orbitals of each conformer are in agreement with the experimental data, indicating that a range of molecular conformations would coexist in an equilibrium sample. Information of the five outer valence molecular orbitals for each conformer is explored in coordinate and momentum spaces using dual space analysis to investigate the conformational processes, which are generated from the global minimum conformer Serl by rotation of C2-C3 （Ser4）, C1 C2 （Ser5） and C1-O2 （Set2 and Ser3）. orbitals 28a, 27a and 26a are identified as the fingerprint orbitals for all the conformational processes.

关键词： serine conformers vertical ionization energies molecular orbital momentum distribution

Fluorescence emission from excited molecular ions in intense femtosecond laser fields

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Frontiers of physics 2013年第1期8卷 34-38页

作者： Yun-Chen Wang Cheng-Yin Wu Yuan-Xing Liu Shao-Hua Xu Qi-Huang Gong State Key Laboratory for Mesoscopic Physics Department of Physics Peking University Beijing 100871 China

Strong fluorescence emissions were observed for nitrogen, carbon monoxide, and carbon dioxide molecules in intense femtosecond laser fields. These emissions can be assigned to the transitions of the molecular ions from the excited electronic states to the ground electronic states. The formation mechanisms were discussed and the lifetimes were measured for these excited molecular ions in intense laser fields.

关键词： tunneling ionization molecular orbital fluorescence

Methyl orbital signatures in 2-amino-1-propanol

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Chinese Physics B 2012年第7期21卷 235-240页

作者：王克栋段坤杰刘玉芳 College of Physics and Information Engineering Henan Normal University Department of Mathematics and Physics Henan University of Urban Construction

Electron density distributions of 2-aminoethanol （2AE） and 2-amino-l-propanol （2AP） are calculated in both the coordinate and the momentum spaces using the B3LYP/TZVP method. Using the dual space analysis, molecular orbital signatures of the methyl substituent in 2AP are identified with respect to 2AE. Relaxations of the geometry and the valence orbital in 2AP are found to be due to the insertion of the methyl group. Five orbitals, not four orbitals, are identified as the methyl signatures. They are orbital 5a in the core shell, orbitals 9a and 10a in the inner valence shell, and orbitals 15a and 16a in the outer valence. In the inner valence shell, the attachment of methyl to 2AE causes a splitting of its orbital 8a into orbitals 9a and 10a of 2AP, whereas in the outer valence shell, the methyl group results in the insertion of an additional orbital pair of 15a and 16a. The frontier molecular orbitals 21a, 20a, and 19a are found to have no significant role in the methylation of 2AE.

关键词： electron density distribution orbital signature of methyl molecular orbital

orbital Calculations of Kaolinite Surface:on Substitution of Al^(3+) for Si^(4+) in the Tetrahedral Sites

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Journal of Wuhan University of Technology(Materials Science) 2007年第4期22卷 661-666页

作者：洪汉烈 The Faculty of Earth Sciences China University of Geosciences

The surface properties of kaolinite were determined using density functional theory discrete variational method （DFT-DVM） and Gaussian 03 program. A SiO4 tetrahedral hexagonal ring with two A1 octahedra was chosen to model the kaolinite crystal. The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level. Both the highest occupied molecular orbit （HOMO） and the lowest unoccupied molecular orbit （LUMO） of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species, but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface, and thus, shows amphoteric behavior. Substitution of Al3^＋ for Si4＋ in the tetrahedral site linking the vacant Al3^＋ octahedra does not increase the surface chemical reactivity of kaolinite, while substitution of Al3^＋ for Si^4＋ in the tetrahedral site with the apex O linking Al3^＋ octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite, especially acting as electron donors. Additionally, substitution of Al3^＋. for Si^4＋ in the tetrahedral site results in the re-balance of charges, leading to the increase of negative charge of the coordinated O atoms of the AlO4 tetrahedra, and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane.

关键词： kaolinite quantum chemistry molecular orbital density of state MOlliken charge

A Theoretical Study on the Photochromic Mechanism of 1-Phenyl-3-methyl-4-(6-hydro-4-amino-5-sulfo-2,3-pyrazine)-pyrazole-5-one

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Chinese Journal of Structural Chemistry 2014年第6期33卷 821-829页

作者：刘岸杰贾殿赠吴冬玲刘浪郭继玺 Institute of Applied Chemistry Xinjiang University

The photochromic mechanism of 1-phenyl-3-methyl-4-（6-hydro-4-amino-5-sulfo-2,3- pyrazine）-pyrazole-5-one has been investigated using the density functional theory（DFT）. The solvent effect is simulated using the polarizable continuum model（PCM） of the self-consistent reaction field theory. According to the crystal structure of the title compound, an intramolecular proton transfer mechanism from enol to keto form was proposed to interpret its photochromism. Bader＇s atom-in-molecule（AIM） theory is used to investigate the nature of hydrogen bonds and ring structures. Time-dependent density functional theory（TDDFT） calculation results show that the photochromic process from enol to keto form is reasonable. The conformation and molecular orbital analysis of enol and keto forms explain why only intramolecular proton transfer is possible. The results from analyzing the energy and dipole moments of enol form, transition state and keto form in the gas phase and in different solvents have been used to assess the stability of the title compound.

关键词： DFT solvent effects AIM TDDFT molecular orbital

Raman Optical Activity and Raman Spectra of Amphetamine Species--Quantum Chemical Model Calculations and Experiments

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American Journal of Analytical Chemistry 2012年第6期3卷 410-421页

作者： Rolf Willestofte Berg Irene Shim Peter Cyril White Salim Abdali Department of Chemistry Technical University of DenmarkLyngbyDenmark ReForensics LincolnUK Biophysical Chemistry Group Department of ChemistryH.C.Orsted Inst.University of CopenhagenCopenhagenDenmark

Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT-molecular orbital calculations by use of the Gaussian 03W program, based on complete geometry minimizations of the conformational energy of the S-(+)-amphetamine molecule, the S-(+)-amphetamine-H+ ion, and the R-(–)-amphetamine molecule. Following this, harmonic frequency calculations have been made, providing information about the cation vibrational bands, expected in salts of single anions (chlorides) as well as in salts of anions with internal bonds (sulfates, hydrogen phosphates, etc.). It shows that the kind of anion should be given better attention, as so far it has often not been the case, when the spectra are employed for identification purposes. The DFT calculations show that the most stable conformations are those allowing for close contact between the aromatic ring and the amine hydrogen atoms. The internal rotational barrier within the same amphetamine enantiomer has a considerable influence on the Raman and ROA spectra. As predicted the experimental ROA spectra were found to depend on the chirality. Two street samples, provided by the London Police, were also measured and compared to the calculated ROA spectra. The street samples were found to contain different enantiomers of the protonated amphetamine-H+ sulfate. According to the present study the AMPH+ ion in aqueous sulfate solution seems to adopt a conformation in which the phenyl and ammonium groups are in transpositions, similar to what has been found in the solid state.

关键词： Amphetamine Raman ROA DFT molecular orbital Drugs Forensic

The Novel Askew and Linear Substituted Structures of Unsaturated Litho-halo Carbenoids

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有机化学 1988年第6期 508-510页

作者： WANG Bing-Ze DENG Cong-Hao (Department of Chemistry,Shandong University,Jinan)XU Lin-Xiao TAO Feng-Gang (Department of Chemistry,Fudan University,Shanghai)

Carbenoids are mechanistically interesting as well as synthetically useful reactive inter-mediates and exhibit more distinct nucleophilicity and electrophilicity than the correspondingfree *** calculations on saturate... 详细信息

关键词： carbenoid structure rearrangement configurition inversion molecular orbital