The structures of the D3h-symmetric molecules dodecafluoro-1,6-distibatriptycene and dodecafluoro-1,6-dibismatriptycene [Z2(C6F4)3 (Z = Sb, Bi)] have been determined in the gas phase by electron diffraction, using the SARACEN method, with restraints obtained from quantum chemical calculations. Several methods of ab initio and density functional theory geometry calculations have been performed and recommendations made as to their relative suitabilities for determining the structures of such species. Calculations using the MP2 method with a small-core pseudopotential (aug-cc-pVQZ-PP) on the Sb and Bi atoms and the 6-311G* basis set on the light atoms were found to give the closest correlation with the experimental results for both molecules. Differences in structure were found depending on whether a large-core or small-core pseudopotential was used on the heavy atoms.
利用 S
ARACEN 方法和量子
化学计算得到的约束条件,通过电子衍射测定了十二
氟-1,6-二三烷三
辛烯和十二
氟-1,6-二三烷三
辛烯 [Z2(
C6F4)3 (Z = Sb, Bi)] 的气相结构。我们采用了几种原子序数和密度泛函理论几何计算方法,并就这些方法对确定此类物质结构的相对适用性提出了建议。使用 MP2 方法和小核伪势(aug-cc-pVQZ-PP)对
锑原子和
铋原子进行计算,并使用 6-311G* 基对轻原子进行计算,结果发现这两种分子与实验结果的相关性最为接近。根据对重原子使用大核还是小核伪势,发现了结构上的差异。