原子团簇P10模型的理论计算

用分子图形学方法设计出26种P10模型，并对其进行了分子力学、PM3半经验量子化学和Hartree-Fock从头算优化。在P10原子团簇模型设计中，磷原子采用一、二、三或四配位。大部分P10的模型是在P9+和P8的模型上分别增加1、2个原子生成的。这些模型包括15种在势能面上局域极小点和11种鞍点（或过渡态）。从模型优化后的能量比较可知，2个四面体P4与1个P2通过4个单键连接的桥式结构最稳定。从最稳定楔状P8可以派生多种构型，其中有一种的能量也相当低。由正四面体P4和楔状P8派生出的结构具有能量优势，它们是构造大分子磷原子团簇的重要的结构基元。在模型几何优化中，得到了带有2个一配位原子的特殊结构，它含有2个三键（1.95A）。

Theoretical Calculations for the Models of Phosphorus Clusters P10

Twenty-six P10 models were acquired with molecular graphics and then carried out the optimizations with molecular mechanics,PM3 semi-empirical and ab intio calculations.The phosphourus atoms could be in one-fold,two-fold,three-fold and four-fold in these models.Most of models are designed by adding one or two atoms in the P8 and P9 clusters.Fifteen models having local minimum on the potential-energy surface are showed.Eleven models(the saddle point or the transitive state)having negative eigenvalue also be displayed.From comparing the total energies of the different models,the structures derived from the tetrahedral P4 by connecting P2 with four single bonds are favor in the total energy.Many models can be derived from cuneane P8 by adding two two-fold atoms,one of them is quite stable also.The tetrahedral P4 and the cuneane P8 Play the important roles in the compositions of the large phosphorus clusters.A special structure containing two one-fold atoms,two triple bond (1.95 ),was obtained after geometry optimization.The total energies of negative eigenvalue are normally higher than the local minimum.