密度泛函算法中基组效应对SiOSi链节的结构、能量和非共价键作用的影响(英文)

The Influences of Basis Set Effect on the Structure,Energy and Non-covalent Interactions of the SiOSi Linkage in DFT Calculations

以二硅氧烷(H3SiOSiH3)为聚硅氧烷中SiOSi骨架的模型分子,以它与水分子形成1∶1氢键复合物作为SiOSi骨架参与非共价相互作用的模型分子,对二重裂分基组6-31G和三重裂分基组6-311G与不同极化函数和弥散函数组合下对二硅氧烷的几何结构、SiOSi线性化能垒及其非键相互作用的预测能力进行了测评.以B3LYP算法来测试基组效应对几何结构和SiOSi线性化能垒的影响,以PBE1PBE算法来考查基组对非共价相互作用的影响.结果表明:1)二硅氧烷的几何结构与线性化能垒对角动量的依赖性较强,至少要使用(3df,p)以上的角动量才会达到收敛;2)二硅氧烷的非共价相互作用同样也要使用(3df,p)以上的角动量才会达到收敛,同时需要包含零点校正能才能得到合理的结合能,但基组叠加效应对结合能的影响则可忽略.

Taking disiloxane as the model molecule of SiOSi in polysiloxane ,and the 1∶1 hydrogen bond compound formed by disiloxane and water molecule as the model molecule which participated in non-covalent interactions ,the paper evaluated the prediction ability about the geometric structure of polysiloxane , SiOSi linearization energy barrier and non-covalent interactions under the combinations of the double-split basis set （6-31G） and the triple-split basis set （6-311G ） with different dipolarization space and diffuse functions . The influences of basis set effect on the geometric structure and SiOSi linearization energy barrier were measured by B3LYP method ,while those on non-covalent interactions were assessed by PBE1PBE method .The results show that the geometric structure and linearization energy barrier of disiloxane are very much dependent on angular momentums ,using at least above 6-311＋ G （3df ,p） angular momentums can achieve convergence .The non-covalent interactions of disiloxane also need to use above 6-311 ＋ G （3df ,p ） angular momentums to achieve convergence .Meanwhile ,the inclusion of zero-point correction energy （ZPE） was found to be important to give a reasonable description of non-covalent binding energy and the basis set superposition error （BSSE） is however neglectable .