中文摘要：

使用Gaussian94程序包和密度泛函方法（DFT）B3LYP以及从头算方法MP2在B3LYP／6-311＋＋G^＊＊基组水平上,对4种三元杂环化合物环丙烷、环氧乙烷、环乙亚胺和硫杂环丙烷进行了全优化,其理论数据和文献数据符合得很好,这表明该方法是可靠的。接着,应用振动模式分析和电子布居分析对它们进行了研究,而且提供了一些热动力学数据。

英文摘要：

Four triatomic heterocyclic compounds, cyclopropane, oxacyclopropane, ethyleneimine and thiirane were fully optimized utilizing Ganssian94 program package with a density functional theory （DFT） method B3LYP and an ab initio method MP2 at 6-311 ＋＋G^＊＊ level, and the theoretical results agrees well with the reference data, which shows that this method is reliable. Subsequently, the vibrational mode analysis and electron population analysis were carried out, and some thermodynamic data were provided.