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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Consistent Theoretical Description of 1,3-Dipolar Cycloaddition Reactions
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Consistent Theoretical Description of 1,3-Dipolar Cycloaddition Reactions

机译：1,3-偶极环加成反应的一致理论描述

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摘要

The cycloaddition reactions of 18 1,3-dipolar molecules to ethylene and acetylene have been reinvestigated by quantum chemical methods that are based on a second-order perturbation treatment of electron correlation.It is found that SCS-MP2 and the new perturbative B2-PLYP density functional provide accurate reaction barriers and outperform MP2 as well as standard density functionals such as B3-LYP.The new second-order based methods have the additional advantage that they perform better with increasing quality of the one-particle space,as is desired for a good quantum chemical method.The errors for the reaction enthalpies are in general larger than for the barriers when compared to CBS-QB3 literature values,which is related to strong changes in the electronic structures,but the deviations are again smaller than with MP2 or B3-LYP and are also more systematic.The results of a detailed basis set study suggest that properly polarized triple-zeta AO basis sets represent a good compromise between accuracy and computational speed.The combination of very inaccurate density functionals with small (double-zeta) basis sets,which yields good results for the initial part of the reactions due to error compensation,is not recommended.
机译：通过基于电子相关性的二次扰动处理的量子化学方法对18个1,3-偶极分子与乙烯和乙炔的环加成反应进行了重新研究，发现SCS-MP2和新的扰动B2-PLYP密度泛函提供了准确的反应障碍，性能优于MP2以及B3-LYP等标准密度泛函。基于二阶新方法的另一优点是，随着单粒子空间质量的提高，它们的性能更好。与CBS-QB3文献值相比，反应焓的误差通常大于势垒的误差，这与电子结构的强烈变化有关，但偏差再次小于MP2或Q2。 B3-LYP也是更系统的。详细基础集研究的结果表明，适当极化的三峰AO基础集代表了良好的折衷方案。不建议使用非常不精确的密度泛函和小的（double-zeta）基集，由于误差补偿，在反应的初始部分会产生良好的结果。

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