Mo_2(PH_3)_4Cl_4分子的空间效应的DFT计算

The DFT calculation of steric effect for Mo(PH_3)_4Cl_4

通过密度泛函理论 (DFT)研究Mo2 (PH3 ) 4 Cl4分子 ,分别对其D2d、D2h、D2 三种旋转构像进行结构优化和能量解析。计算表明 ,在D2d、D2h、D2 三种旋转构像中 ,Mo—Mo键长分别为 2 .180 ,2 .192 ,2 .32 9 ,其SCF能量分别为 - 2 2 7.3193a .u ,- 2 2 7.2 0 91a .u ,- 2 2 7.0 4 14a .u。我们认为 ,金属原子d轨道的δ重叠程度是导致D2d和D2h构像比D2 构像稳定的原因 。

We have studied Mo(PH 3) 4Cl 4 molecule by density functional theory, the optimization and energy decomposition were carried under D 2d ,D 2h ,D 2 symmetry restriction, respectively .We found that the Mo-Mo bond distance is 2.180?, 2.192? and 2.329? for D 2d , D 2h and D 2 conformation respectively and the SCF energy is -227.3193 a.u, -227.2091 a.u,-227.0414 a.u of the three conformation respectively. From which we got that theδoverlap of the d orbital of the metal atoms caused to D 2d 和D 2h conformations are more stable than D 2 conformation, the reason of D 2d conformation is more stable than D 2h conformation is steric effect.