P_（14）原子簇的理论研究

Theoretical Studies on P_(14) Cluster

以Ｐ_２、Ｐ_４（Ｔｄ）、Ｐ_８（Ｃ_（２ｖ））及Ｐ_（１０）（Ｃ_（２ｖ））为结构单元设计了Ｐ_２＋Ｐ_４（Ｔ_ｄ）＋Ｐ_８（Ｃ_（２ｖ））→Ｐ_（１４）（Ｃ_ｓ）（Ａ）、Ｐｓ（Ｃ_（２ｖ）＋３Ｐ_２→Ｐ_（１４）（Ｃ_（２ｖ））（Ｉ）（Ｂ）、Ｐ_（１０）（Ｃ_（２ｖ）＋２Ｐ_２→Ｐ１４（Ｃ_（２ｖ））（Ⅱ）（Ｃ），利用从头算Ｇａｕｓｓｉａｎ－９４程序，选择６－３１Ｇ基组，对４种结构单元及Ｐ_（１４）原子簇的３种几何构型Ｃｓ、Ｃ_（２ｖ）（Ⅰ）、Ｃ_（２ｖ）（Ⅱ）进行全优化。相对能量的计算结果表明，Ｐ_（１４）（Ｃ_ｓ）与Ｐ_（１４）（Ｃ_（２ｖ））（Ⅰ）构型稳定。进一步设计（７／２）Ｐ_４（Ｔ_ｄ）→Ｐ_（１４）（Ｄ）及７Ｐ_２→Ｐ_（１４）（Ｅ），其相对能量表明，Ｐ_（１４）（Ｃ_ｓ）构型是稳定的．磷与磷连结单键键长范围为０．２２０～０．２２８ｎｍ，双键键长范围为０．２００～０．２０２ｎｍ，与实验结果大体相当。

P_2+P_4(T_d)+P_8(C_(2v))→P_(14)(C_s)(A),P_8(C_(2v))+3P_2→P_(14)(C_(2v))(Ⅰ)(B),P_(10)(C_(2v))+2P_2→P_(14)(C_(2v))(Ⅱ)(C)are designed by acting P_2,P_4 (T_d),P_8(C_(2v))and P_(10)(C_(2v))as the structural units, Using Gaussian-94 ab initio program, the four kinds of structural units and three configurations of P_(14) cluster[Cs,C_(2v)(Ⅰ),C_(2v)(Ⅱ)] are performed by full geometric optimization by choosing 6-31G basis set. The calculated results of relative energy show that the configurations of P_(14)(C_s) and P_(14)(C_(2v))(Ⅰ)are stable,Furthermore, we design(7/2)P_4(T_d)→P_(14)(D),7P_2→P_(14)(E), the relative energy shows that the structure of P_(14) (C_s)is stable, The results of the three structures of the P_(14) cluster show that the range of single bond lengths which link phosphorous atom is 0. 220￣0. 228 nm,the range of double bond lengths is 0. 200￣0.202 nm, which are in accordance with the experimental values.