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LOW ENERGY PATHS AND REORIENTATION OF SIDE-GROUPS OF POLYMERS DURING CONFORMATIONAL STATE TRANSITION
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作者 Xiao Zhen YANG Li Ling HE +1 位作者 Bao Zhu AN De Zhu MA Polymer Physics Laboratory, Academia Sinica. Beijing 100080 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第7期631-634,共4页
INTRODUCTION The conformational state transition of polymer chains relates to crystallization processes, migration ofthe chains in solution, fluctuation of the end-to-end distance of random coils, and the relaxation a... INTRODUCTION The conformational state transition of polymer chains relates to crystallization processes, migration ofthe chains in solution, fluctuation of the end-to-end distance of random coils, and the relaxation and phasetransitions of polymers. A description of the conformational state transition requires questions about; 1) howmany stable conformational states for a specific σ bond; 2) the barriers between the states; 3) the mechanismof the conformational transition; 4) any cooperative behavior during the transition. Flory and his coworkers 展开更多
关键词 LOW energy PATHS AND REORIENTATION OF SIDE-GROUPS OF POLYMERS DURING CONFORMATIONAL state transition
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Conservation of Energy in Classical Mechanics and Its Lack from the Point of View of Quantum Theory
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作者 Stanisław Olszewski 《Journal of Modern Physics》 2016年第16期2316-2328,共13页
It is pointed out that the property of a constant energy characteristic for the circular motions of macroscopic bodies in classical mechanics does not hold when the quantum conditions for the motion are applied. This ... It is pointed out that the property of a constant energy characteristic for the circular motions of macroscopic bodies in classical mechanics does not hold when the quantum conditions for the motion are applied. This is so because any macroscopic body—lo-cated in a high-energy quantum state—is in practice forced to change this state to a state having a lower energy. The rate of the energy decrease is usually extremely small which makes its effect uneasy to detect in course of the observations, or experiments. The energy of the harmonic oscillator is thoroughly examined as an example. Here our point is that not only the energy, but also the oscillator amplitude which depends on energy, are changing with time. In result, no constant positions of the turning points of the oscillator can be specified;consequently the well-known variational procedure concerning the calculation of the action function and its properties cannot be applied. 展开更多
关键词 Classical Mechanics and Conservation of energy Motion Quantization of Macroscopic Bodies energy and Time of transitions between Quantum states Harmonic Oscillator Taken as an Example
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AIM Study on the Reaction of CH2SH Radical with Fluorine Atom
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作者 Cui-hong Suna Yan-li Zeng +1 位作者 Ling-peng Meng Shi-jun Zheng 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第2期123-130,共8页
The reaction of CH2SH radical with fluorine atom was studied at the levels of B3LYP/6-311G(d,p) and MP2(Full)/6-311G(d,p). The computational results show that the reaction has three channels and proceeds by the ... The reaction of CH2SH radical with fluorine atom was studied at the levels of B3LYP/6-311G(d,p) and MP2(Full)/6-311G(d,p). The computational results show that the reaction has three channels and proceeds by the addition of fluorine atoms on carbon or sulfur sites of CH2SH, forming initial intermediates. The calculated results show that the channel, in which fluorine attaches to the carbon atom to form CH2S and HF, is the most likely reaction pathway. Topological analysis of electron density was carried out for the three channels. The change trends of the chemical bonds on the reaction paths were discussed. The energy transition states and the structure transition regions (states) of the three channels were found. The calculated results show that the structure transition regions are broad in unobvious exothermic reactions or unobvious endothermic reactions, and are narrow in obvious exothermic reactions or obvious endothermic reactions. 展开更多
关键词 Radical reaction energy transition state Structure transition state Structure transition region Topological analysis of electronic density
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Theoretical Study on the C-H Activation in Decarbonylation of Acetaldehyde by NiL_2(L=SO_3CH_3) Using Density Functional Theory
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作者 刘红飞 JIA Tiekun MIN Xinmin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第6期1170-1172,共3页
Density functional theory calculations were carried out to explore the potential energy surface(PES) associated with the gas-phase reaction of Ni L2(L=SO3CH3) with acetone. The geometries and energies of the react... Density functional theory calculations were carried out to explore the potential energy surface(PES) associated with the gas-phase reaction of Ni L2(L=SO3CH3) with acetone. The geometries and energies of the reactants, intermediates, products and transition states of the triplet ground potential energy surfaces of [Ni, O, C2, H4] were obtained at the B3LYP/6-311++G(d,p) levels in C,H,O atoms and B3LYP/ Lanl2 dz in Ni atom. It was found through our calculations that the decabonylation of acetaldehyde contains four steps including encounter complexation, C-C activation, aldehyde H-shift and nonreactive dissociation. The results revealed that C-C activation induced by Ni L2(L=SO3CH3) led to the decarbonylation of acetaldehyde. 展开更多
关键词 density functional theory decarbonylation transition state energy C-C activation
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