簇合物(F_2GaN_3)_n(n=1～4)的理论研究

Theoretical studies on the clusters (F_2GaN_3)_n(n=1～4)

采用密度泛函理论B3LYP/6-311＋G＊方法,计算研究了（F2GaN3）n（n=14）簇合物的结构和性质.研究表明,簇合物（F2GaN3）n（n=24）的优化构型均拥有Ga—Nα—Ga连接的环状结构.讨论了几何参数随聚合度的变化关系.三聚体的船式构象较椅式构象的能量低16 kJ.mol-1,具有S4对称性的四聚体较Cs对称性的四聚体稳定.通过振动分析,获得它们的IR谱并进行归属.基于统计热力学原理,由计算IR谱获得热力学函数（C0p,m、S0m及H0m）均随聚合度n以及温度的增加而呈线性递增.较高温度下,多聚化在热力学上仍是有利的.

The structures and properties of the clusters（F2GaN3）n（n=1～4） have been investigated by the density functional theory B3LYP/6-311＋G method.The results show that all the clusters（F2GaN3）n（n=2～4） are cyclic structures containing Ga—Nα—Ga linkages.The relationships between geometrical parameters and oligomerization degree n are discussed.The boat-like conformation lies 16 kJ·mol-1 lower in energy than the chair-like isomer for the trimers.The tetramer possessing S4 symmetry is preferred over the isomer possessing Cs symmetry.The infrared spectra have been obtained and assigned by harmonic vibrational analysis.Thermodynamic properties（C0p,m,S0m and H0m） derived from the infrared spectra on the basis of statistical thermodynamic principles are linearly correlated with the oligomerization degree n as well as the temperature.The oligomerizations are thermodynamically favorable under high temperature