【摘要】 在MP2/6 31G(d)和MP2(FC)/6 311+G(d,p)水平上,对硫代甲酰胺(HC-SNH2)及其3种构型双聚体进行几何全优化计算,经振动频率分析,确认为势能超曲面上的稳定驻点.然后在MP2/6 311++G(2df,2p)水平上进行单点能计算和基组重叠误差(BSSE)校正以获得相互作用能.并利用自然键轨道(NBO)理论和分子中的原子(AIM)理论探讨HCSNH2之间相互作用的本质.更多还原

【Abstract】 The optimized geometries and vibrational frequencies of HCSNH₂ and thioformamide dimers have been calculated by using the ab initio method at the MP2/631G（d） and MP2（FC）/6311+G（d,p） level.The nonminimum structures with negative vibrational frequencies are excluded. The lowest energy conformer of these dimers is cyclic structure with N-H…S and C-H…S hydrogen bonds in the same planes.No significant changes are observed in the geometries of the monomers in their complexed state.The most characteristic geometrical properties of the complex are the lengthening of the contacting N-H bonds by 1.1¹.2 pm,and the general shortening of the contacting C-H bonds by 0.005⁰.047 pm with respect to their monomers.The interaction energies of dimers have been corrected by the basis set superposition error（BSSE） using the full BoysBernardi counterpoise correction scheme.The corrected complex interaction energies of three structures at MP2/6311++G（2df,2p）// MP2（FC）/631+G（d,p） level are 47.98,36.23 and 22.33 （kJ/mol）,respectively.The interaction energies indicate that C-H…S is weak hydrogen bonds.The results of natural bond orbital population analysis reveals that there is only a small chargetransfer in the process of forming the complexes.更多还原