团簇Ti_3P_2结构及成键特点

Study on stable structure and bonding properties of cluster Ti_3P_2

为了进一步了解Ti-P体系的性质,应用密度泛函理论方法,在B3LYP/Lan12dz的基础上,对团簇Ti_3P_2进行构型优化和虚频筛选,得到了7种稳定构型,其中单重态5种,三重态2种。团簇Ti_3P_2存在4种稳定几何构型,分别为平面五边形、戴帽三角锥、四棱锥和三角双锥;根据能量、键长和键级的综合比较得到,三角双锥构型1(1)最稳定;大多数稳定构型以单重态形式存在;团簇构型随能量的增加,结构稳定性降低,反应3Ti+2P→Ti_3P_2的自发性在不断减小;Ti-P键键级占总键级的比例最高,所以团簇Ti_3P_2中金属-非金属键(Ti-P)是主要的贡献者。

In order to further understand the properties of Ti-P system,by using the density functional theory method,configuration optimization and virtual frequency screening of cluster Ti3P2 were conducted on the basis of B3 LYP/Lan12 dz. Seven stable configurations were found,of which five are singlet states and two are triplet states. In the cluster Ti3P2 there exist four types of stable geometrical configurations,namely the planar pentagon,the capped trigonal pyramid,the rectangular pyramid and the trigonal biyramid. According to comprehensive comparison of energy,bonding length and bonding level,the trigonal biyramid configuration 1（1）is the most stable whereas most of the stable configurations exist in the form of singlet states. With the increase of energy,the stability of the cluster configuration structure decreases,and the spontaneity of the reaction3 Ti＋2 P → Ti3P2 is reduced. The ratio between the Ti-P bonding level and the total bonding level is the highest and thus the metal-nonmetallic bond（Ti-P）is the main contributor in the cluster Ti3P2.