采用密度泛函理论中的B3LYP方法,结合从头算的CCSD(T)方法对Ti2Bn(n=1—10)团簇的稳定性和电子性质进行了研究.发现两个Ti原子的掺杂导致B n团簇结构发生了根本性变化.随着n的增大,Ti2Bn团簇结构生长非常规律.所有的最稳定结构都可看成双锥结构,并且两个Ti原子处在双锥结构的锥顶.根据二阶差分能量分析,得出Ti2Bn(n=1—10)团簇的幻数是6,7和8.进一步分析了团簇的Ti原子解离能、B原子解离能以及团簇的电子亲和势和电离势.这些能量分析表明Ti2B6团簇既有良好的热力学稳定性,又有良好的动力学稳定性.应用前线轨道理论,对Ti原子与B6之间的成键进行了分析,了解其稳定性的根源.
Structures and stabilities of Ti2Bn(n = 1–10) clusters have been systematically investigated by using the densityfunctional theory B3 LYP method and ab initio CCSD(T) method. It is found that the ground state structures of the B n clusters are substantially modified by doping two Ti atoms. Ti2Bn clusters have very clear growth patterns, namely to form bipyramid. All the most stable Ti2Bn can be visualized as bipyramids with the two Ti atoms located at the two apexes. Ti2B6, Ti2B7 and Ti2B8are confirmed to be the magic number clusters based on the analysis of the second-order difference of energies. The dissociation energies, vertical ionization potentials and vertical electron affinities of Ti2Bn isomers are discussed. Ti2B6 cluster is found to be stable both kinetically and thermodynamically.