Aun^-(n=3~8)离子团簇的结构演变与电子性质研究

Study of Structural Evolution and Electronic Properties of Au_n^- Ionic Clusters

利用密度泛函PW91方法和TZVPP基组,研究Au_n^-(n=3~8)离子团簇的结构演化和电子特性。结果显示:所有基态金负离子团簇为平面构型,其生长模式存在奇偶效应,即奇数金负离子团簇在能形成高对称结构处加上一个Au原子后,经过小的弛豫便可生成偶数金负离子团簇;同时,在此基态结构下,电离能的理论值与实验结果符合较好,能量二阶差分与能级间隙也表现出相同的奇大偶小的特点,这说明奇数金负离子团簇比偶数金负离子团簇具有较高的物理和化学稳定性。

The structural evolution and electronic properties of Aun clusters have been studied using density functional theory at the PW91/TZVPP level. The results indicate that all the ground state clusters possess a planar configuration and its growth patterns display an odd - even effect, namely, combined with an Au atom on the high symmetry direction, the Aun - cluster with odd n can form the Aun＋1 - cluster by a small relaxation. Simuhaneously, the calculated ionization potential based on the ground state is good agreement with experimental value. The energy second -order difference and energy gap show same odd -even oscillation. This implies that the Aun clusters with odd n have higher physical and chemical stability than that with even n.