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计算任何固体和表面的电子结构之前,必须构造一个物理模型,由于实际的结构模型是有限的,这就需要正确考虑边界条件的影响。迄今,已经提出了一些不同的边界处理方案。一种是用一个单价原子来饱和原子簇边界上的一个游离键,所用原子通常是氢原子或碱金属原子。更好的处理是引入改变了部分或全部量子化学参数的赝原子来构成边界,这种方法称为模拟边界条件。 相似文献
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Carbenoidsandcompoundswithcarbenoidnatureareofspecialinterestsynthetically.ThesecompoundsreactnotonlywithelectrophilesE(asall“carbanions”do),butalsowithnucleophileslikeRLi.Theambidentnatureofcarbenoidshasledtomanyinvestigationsoftheirstructuresandisome… 相似文献
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本文用HF/STO-3G解析梯度方法计算了甲基环丙烷卡宾重排反应的8个构型,它们代表4个反应类型.计算结果表明,甲基的H原子对卡宾碳的1,3迁移遵从端端告拢机理.环丙烷上的H原子1,2迁移活性遵从夹有相似文献
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The titled isomerizaton of methylsilene has been studied at ab initio level. Theharmonic vibrational frequencies of reactant, product and transition state, the barrier energy, reaction heat, equilibrium constant and rate constant are calculated. The results indicate that this reaction is exothermic, spontaneous and high temperature above 900 K is favourable for the isomerization. The prediction is in agreement with experiment. 相似文献
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Quantum scattering LCAC-SW theory studies on reaction probabilities of three-dimensional H+H_2(υ,j)→H_2(υ′, j′)+H reaction 总被引:1,自引:0,他引:1
InlightofKohnvariationtheory,Millerconstructedanewquantumreactivescatteringmethod:theSmatrixvariationmethod[1,2],whichisatypicaloneinwhichalgebraicmethodisusedtosolvedirectlytheSchrdingerequation.Becausethemethodincludesnaturallytheboundaryconditions,thew… 相似文献