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利用超分子二阶到四阶多体微扰理论和扩展的相关一致基组(aug-cc-pVTZ)结合有效的中点键函数(3s3p2d1f1g)计算水二聚物的平衡结构和分子间相互作用势,并用平衡方法修正基组重叠误差.在MP2/aug-cc-pVTZ理论级别优化水二聚物几何构型.与正常优化的结果相比,平衡修正优化得到的RO-O和α值分别轻微的增加0.002 nm和0.19°,同时,θ值减小0.013°.在MP2水平利用扩展的相关一致基组结合有效键函数,预言了RO-O和ΔECP值分别为0.0923 nm和-4.86 kcal/mol,计算结果与实验值符合得很好.用exp-4.2势函数拟合分子间相互作用能的离散点,拟合结果与从头算计算的结果一致.
The equilibrium structure and intermolecular interaction of water dimers were calculated using the second order to fourth order multi-body perturbation theory and the augmented coherent basis set (aug-cc-pVTZ) combined with an effective midpoint bond function (3s3p2d1f1g) And the equilibrium error of the base set was corrected by the equilibrium method. The geometry of water dimer was optimized at MP2 / aug-cc-pVTZ theoretical level.Compared with the results of normal optimization, RO-O and α A slight increase of 0.002 nm and 0.19 ° and a decrease of θ of 0.013 °. At the level of MP2, using the extended correlation basis set combined with the effective bond function, the RO-O and ΔECP values were predicted to be 0.0923 nm and -4.86 kcal / mol, and the calculated results are in good agreement with the experimental data.Fixed points of the intermolecular interaction energies are fitted by the exp-4.2 potential function, and the fitting results are consistent with the ab initio calculations.