Cu3Ti原子簇结构与光谱的密度泛函理论研究

Density Functional Theory Studies on Structure and Spectrum of Cu_3Ti Cluster

异核金属合金是非常重要的材料,Cu3Ti具有形状记忆、高强度和声音吸收特性。由于实验中只观察到一条拉曼谱线,但其稳定结构并不清晰。文章利用密度泛函理论中的SVWN5,B3LYP和BPW91方法,分别采用lanl2dz,6-31g,6-311g,6-311g(d),6-311+g(2df)和6-311+g(3d2f)基组对Cu3Ti多种可能的结构和振动光谱进行了研究。结合实验结果分析,表明其基态为自旋多重度为4的e型C2v对称性结构,基组对于频率和原子间距的影响比较大;并与实验拉曼光谱进行了对比。

Bulk intermetallic Ti-Cu compounds have been found to possess special properties, including increased hardness, as well as displaying enhanced sound absorption and e shape memory. Since only one Raman progression is observed, there is not sufficient information to determine the structure of TiCu3. The different structures and vibrational frequencies of the Cu3 Ti cluster were studied by means of the density functional theory with SVWN5, B3LYP and BPWgl methods at basis sets of lanl2dz 6-31g, 6-311g, 6-311g（d）, 6-311＋g（2df） and 6-311＋g（3d2f）. The calculated results show that the ground state of the Cu3Ti cluster is a e-type structure with the C2v point group symmetry, and the bond lengths and vibrational frequencies of Cu3T are considerably dependent on the variation of basis sets. We observed only a single Rarnan progression in approximately 300 cm^-1. This progression is most likely the totally symmetric stretch. The computed and observed Rarnan spectra were also compared with each other.