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The relative energies of polypeptide conformers predicted by linear scaling second-order M?ller-Plesset perturbation theory
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作者 GUO Yang LI Wei +1 位作者 YUAN DanDan LI ShuHua 《Science China Chemistry》 SCIE EI CAS 2014年第10期1393-1398,共6页
We describe an implementation of the cluster-in-molecule (CIM) resolution of the identity (RI) approximation second-order Moller-Plesset perturbation theory (CIM-RI-MP2), with the purpose of extending RI-MP2 cal... We describe an implementation of the cluster-in-molecule (CIM) resolution of the identity (RI) approximation second-order Moller-Plesset perturbation theory (CIM-RI-MP2), with the purpose of extending RI-MP2 calculations to very large systems. For typical conformers of several large polypeptides, we calculated their conformational energy differences with the CIM-RI-MP2 and the generalized energy-based fragmentation MP2 (GEBF-MP2) methods, and compared these results with the density functional theory (DFT) results obtained with several popular functionals. Our calculations show that the conformational energy differences obtained with CIM-RI-MP2 and GEBF-MP2 are very close to each other. In comparison with the GEBF-MP2 and CIM-RI-MP2 relative energies, we found that the DFT functionals (CAM-B3LYP-D3, LC-ωPBE-D3, M05-2X, M06-2X and coB97XD) can give quite accurate conformational energy differences for structurally similar conformers, but provide less-accurate results for structurally very different conformers. 展开更多
关键词 cluster-in-molecule generalized energy-based fragmentation second-order moller-plesset perturbation theory resolution of the identity relative energy
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Theoretical Study on the Mechanism of the Cycloaddition Reaction between Methylidenesilene and Ethylene 被引量:2
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作者 卢秀慧 于海彬 +1 位作者 徐曰华 武卫荣 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2006年第3期307-310,共4页
The mechanism of a cycloaddition reaction between singlet methylidenesilene and ethylene has been investigated with MP2/6-31G^* and B3LYP/6-31G^* methods, including geometry optimization and vibrational analysis for... The mechanism of a cycloaddition reaction between singlet methylidenesilene and ethylene has been investigated with MP2/6-31G^* and B3LYP/6-31G^* methods, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies of the involved conformers were calculated by CCSD(T)//MP2/6-31G* and CCSD(T)//B3LYP/6-31 G* methods, respectively. The results show that the dominant reaction pathway of the cycloaddition reaction is that a complex intermediate is firstly formed between the two reactants through a barrier-free exothermic reaction of 13.3 kJ/mol, and the complex is then isomefized to a four-membered ring product P2,1 via a transition state TS2.1 with a barrier of 32.0 kJ/mol. 展开更多
关键词 methylidenesilene cycloaddition reaction potential energy surface second-order moller-plesset perturbation and density functional theory
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Theoretical Study on the Mechanism of the Cycloaddition Reaction between Alkylidene Carbene and Ethylene 被引量:1
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作者 卢秀慧 翟利民 武卫荣 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2004年第1期24-27,共4页
The mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second-order Moller-Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, ... The mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second-order Moller-Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, vibrational analysis and energetics have been calculated for the involved stationary points on the potential energy surface. The results show that the title reaction has two major competition channels. An energy-rich intermediate (INT) is firstly formed between alkylidene carbene and ethylene through a barrier-free exothermic reaction of 63.62 kJ/mol, and the intermediate then isomerizes to a three-membered ring product (Pl) and a four-membered ring product (P2) via transition state TS1 and TS2, in which energy barriers are 47.00 and 51.02 kl/mol. respectively. PI is the main product. 展开更多
关键词 alkylidene carbene cycloaddition reaction second-order moller-plesset perturbation theory potential energy surface
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