共查询到20条相似文献,搜索用时 156 毫秒
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1998年10月13日,瑞典皇家科学院宣布:将1998年度诺贝尔化学奖授予两位成就卓著的量子化学家--美国加利福尼亚大学的沃尔特·库恩 (Walter Kohn, 1923年出生) 和美国西北大学的约翰·波普尔 (John A. Pople, 1925年出生),以奖励沃尔特·库恩的密度泛函理论和约翰*波普尔的量子化学计算方法对化学的巨大贡献.在瑞典皇家科学院发布的公告中,量子化学被提到前所未有的重要地位--量子化学理论和计算的丰硕成果被认为正在引起整个化学的革命.量子化学家几十年的辛勤耕耘得到了充分的肯定.这标志着古老的化学已发展成为理论和实验紧密结合的科学. 相似文献
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量子化学的第二次革命——1998年诺贝尔化学奖简介 总被引:1,自引:0,他引:1
简单介绍了1998年诺贝尔化学奖获得者以及30多年来他们在发展量子化学理论与计算方法方面的卓越贡献,文中还简要地介绍了量子化学计算在化学中的应用。 相似文献
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简单介绍了1998年诺贝尔化学奖获得者以及30多年来他们在发展量子化学理论与计算方法方面的卓越贡献。文中还简要地介绍了量子化学计算在化学中的应用。 相似文献
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Gaussview在化学教学中的一些应用 总被引:1,自引:0,他引:1
Gaussian量子化学计算程序包是美国Gaussian公司开发的一个功能强大的量子化学综合软件包。可执行各类不同精度的分子轨道计算(包括Hartree-Fock水平从头算(HF)、Post-HF从头算、密度泛函理论(DFT)以及多种半经验量子化学方法),进行分子和化学反应性质的理论预测。目前已成为国 相似文献
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随着大尺度模拟、机器学习等前沿应用的兴起,分布式计算越发成为重要的计算研究手段.然而分布式计算由于多节点导致的软硬件局限,在科学计算、机器学习等领域的应用仍会存在一些问题.本工作将编码分布式计算应用到量子化学领域,通过借鉴梯度编码方案,一方面解决分布式量子化学计算中的掉队节点问题;另一方面增加量子化学分布式计算的自动纠错能力,减少计算过程耗费的人力物力,以期实现自动化的容错量子化学计算.此外,也提出了编码复用的计算思路,能够简单有效地使用更多的计算资源在设定的容错能力上进行分布式计算.最后将此计算方案应用到计算P38蛋白与配体的结合能上,将使用编码计算得到的结果与真实的结果进行对比,验证此方案的准确性及其在自动化容错量子化学计算方面的应用潜力. 相似文献
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Preuss M Schmidt WG Seino K Furthmüller J Bechstedt F 《Journal of computational chemistry》2004,25(1):112-122
We present equilibrium geometries, vibrational modes, dipole moments, ionization energies, electron affinities, and optical absorption spectra of the DNA base molecules adenine, thymine, guanine, and cytosine calculated from first principles. The comparison of our results with experimental data and results obtained by using quantum chemistry methods show that in specific cases gradient-corrected density-functional theory (DFT-GGA) calculations using ultrasoft pseudopotentials and a plane-wave basis may be a numerically efficient and accurate alternative to methods employing localized orbitals for the expansion of the electron wave functions. 相似文献
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Using the results of quantum chemistry, thermodynamic and kinetic calculations for this experimentally well studied reaction has been carried out. The adaptability of the computational results of diffrent quantum chemistry schemes (considering electronic correlation or not, and basis size) has been analyzed for the chemical reactivities (thermodynamic functions and kinetic parameters). The calculated results are in good agreement with the experimental ones using the larger basis set and considering electronic correlation, but are bad on the contrary. In addition, a set of exact thermodynamic functions and kinetic parameters has been given. 相似文献
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In the last decade, we have witnessed substantial progress in the development of quantum chemical methodologies. Simultaneously, robust solvation models and various combined quantum and molecular mechanical (QM/MM) approaches have become an integral part of quantum chemical programs. Along with the steady growth of computer power and, more importantly, the dramatic increase of the computer performance to price ratio, this has led to a situation where computational chemistry, when exercised with the proper amount of diligence and expertise, reproduces, predicts, and complements the experimental data. In this perspective, we review some of the latest achievements in the field of theoretical (quantum) bioinorganic chemistry, concentrating mostly on accurate calculations of the spectroscopic and physico-chemical properties of open-shell bioinorganic systems by wave-function (ab initio) and DFT methods. In our opinion, the one-to-one mapping between the calculated properties and individual molecular structures represents a major advantage of quantum chemical modelling since this type of information is very difficult to obtain experimentally. Once (and only once) the physico-chemical, thermodynamic and spectroscopic properties of complex bioinorganic systems are quantitatively reproduced by theoretical calculations may we consider the outcome of theoretical modelling, such as reaction profiles and the various decompositions of the calculated parameters into individual spatial or physical contributions, to be reliable. In an ideal situation, agreement between theory and experiment may imply that the practical problem at hand, such as the reaction mechanism of the studied metalloprotein, can be considered as essentially solved. 相似文献
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ZHANG Ding YAN Hui ZHANG Huan QI Lu Beijing National Laboratory for Molecular Sciences 《高等学校化学研究》2011,(3):478-481
A new solid polymer electrolyte PEO20-LiTf-Urea1.5 was prepared by solution casting technique. The energy of frontier orbitals for the components of the electrolyte was predicted by quantum chemistry calculations, and TG stability and electrochemical features were measured. Urea exhibited a lower HOMO energy than PEO, implying its enhanced stability against electrochemical oxidation. Experimentally addition of urea increases the ionic conductivity, which guarantees conductivity requirement for lithium ion b... 相似文献
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In this paper we propose a topological rule to account for both the simple and conjuctopolyhedral boranes and heteroboranes. The calculated results are in good agreement with the real molecular formulas. Furthermore, we have also made some quantum chemistry calculations to verify and discuss the rule. 相似文献
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Johannes R. Loeffler Emanuel S. R. Ehmki Julian E. Fuchs Klaus R. Liedl 《Journal of computer-aided molecular design》2016,30(5):391-400
Urea derivatives are ubiquitously found in many chemical disciplines. N,N′-substituted ureas may show different conformational preferences depending on their substitution pattern. The high energetic barrier for isomerization of the cis and trans state poses additional challenges on computational simulation techniques aiming at a reproduction of the biological properties of urea derivatives. Herein, we investigate energetics of urea conformations and their interconversion using a broad spectrum of methodologies ranging from data mining, via quantum chemistry to molecular dynamics simulation and free energy calculations. We find that the inversion of urea conformations is inherently slow and beyond the time scale of typical simulation protocols. Therefore, extra care needs to be taken by computational chemists to work with appropriate model systems. We find that both knowledge-driven approaches as well as physics-based methods may guide molecular modelers towards accurate starting structures for expensive calculations to ensure that conformations of urea derivatives are modeled as adequately as possible. 相似文献
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准分子泵浦钠金属激光器(XPNaL)在钠导星中有着极为重要的应用。但是,传统的准分子对,例如Na-He和Na-Ar等对相对于泵浦源的吸收系数很小。本文对Na-Ar、Na-Xe、Na-CH4、Na-C2H6四个体系进行了研究,从荧光实验和结合能的高精度量化理论计算两方面来探究比较好的准分子对。实验结果表明:这四个准分子对体系的荧光强度曲线峰面积比为1.0 : 6.4 : 4.9 : 10.4。同时,通过CCSD(T)手段和基组外推法对Na-Ar、Na-Xe、Na-CH4和Na-C2H6准分子对的结合能计算结果分别为52.8、124.5、117.7和150.0cm-1。因此,可以推断量化计算与实验结果能够较好地符合。随后, Na-C2H6准分子对从实验和理论两方面被发现是效率最高的体系,更有希望被发展成为高能准分子宽带泵浦钠金属激光器。本工作还证明了采用大基组对结合能的高精度量化计算,对用于准分子宽带泵浦碱金属激光器的准分子对筛选是很好的评判标准。 相似文献
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The nature and strength of the interactions occurring between epoxides and CO(2) have been investigated by combining infrared spectroscopy with quantum chemistry calculations. A series of infrared absorption experiments on four model epoxide molecules highly diluted in supercritical CO(2) have been performed at constant temperature T = 40 °C for various CO(2) pressures varying from 1 to 30 MPa. Then, we carried out a theoretical analysis based on quantum chemistry calculations using Density Functional Theory (B3PW91 and CAM-B3LYP) and ab initio (MP2) computational methods. A very good agreement between experimental and calculated vibrational frequency shifts of the epoxide ring vibrations group was obtained using the CAM-B3LYP functional, hence validating the calculated optimized geometries of the epoxide-CO(2) complexes. Whatever the epoxide considered, CO(2) is found to be on average above the oxygen atom of the epoxy ring and interacts with the carbon atom of CO(2) through a Lewis acid-Lewis base type of interaction. The substituents on the epoxide ring are found to influence the stability of the epoxide-CO(2) complexes mainly because of the partial charge on the oxygen atom that is sensitive to the nature of the substituent. 相似文献
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Sambhu N. Datta 《Journal of Chemical Sciences》1994,106(2):445-466
A brief review of relativistic quantum chemistry is given here. Relativistic effects and their importance in chemistry are
discussed. An outline of different theoretical aspects is presented. Aspects of variation techniques relevant to relativistic
calculations are discussed in detail. These involve the derivation of min-max theorems for Dirac, Dirac-Hartree-Fock and Dirac-Coulomb
calculations. The consequence of relativistic Hamiltonians being unbounded are also discussed for other lines of investigation.
The upper bounds derived are physically interpreted. Sample Dirac-Hartree-Fock results for the Be atom, calculated using both
STO and GTO bases for the nonrelativistic orbitals and the upper components of the relativistic orbitals, are given. The inadequacy
of the so-called kinetically balanced basis set is discussed and illustrated with these results. The importance of the variational
or dynamical balance and hence the merit of the LCAS-MS scheme is pointed out. The possibility of calculating quantum electrodynamical
pair energy from relativistic configuration interaction calculations on a two-electron atom is discussed and exemplified.
The present status of relativistic molecular calculations is briefly reviewed. Conclusions on the aspects of variational analysis
and molecular calculations are enclosed. 相似文献
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Allouche AR Aubert-Frécon M Graveron-Demilly D 《Physical chemistry chemical physics : PCCP》2007,9(24):3098-3103
Chemical shifts delta and spin-spin coupling constants J have been calculated using quantum chemistry approaches for the gamma-amino butyric acid GABA which is a brain metabolite. Two theoretical methods HF and DFT/B3LYP, two basis sets 6-31G* and 6-311+G(2d,p) and two gauge-invariant methods CSGT and GIAO have been used. From delta and J values, NMR spectra have been obtained from the strongly coupled spin system Hamiltonian using the NMR-SCOPE package. Solvent effects have been considered within the polarisable continuum model. Comparisons between calculated and experimental NMR spectra at 300 MHz show that our best results correspond to the B3LYP/6-311+G(2d,p)-GIAO calculations. They are seen to be in good agreement with experiment. This demonstrates the usefulness of quantum chemistry methods for estimating NMR spin Hamiltonian parameters involved in specific algorithms used for quantitation of metabolites such as GABA. 相似文献