密度泛函理论研究Sc_nO(n=1—9)团簇的结构、稳定性与电子性质

Density functional theory study of the geometry,stability and electronic properties of Sc_nO(n=1—9) clusters

采用基于密度泛函理论的BP86/CEP-121G(O原子采用6-311G**基组)方法,对ScnO(n=1—9)团簇的几何结构、能量与稳定性、电子结构性质及其随团簇尺寸的变化趋势进行了研究.随着团簇原子个数的增加,O原子从位于Scn团簇结构的边缘转变为占据团簇的内部位置.O原子的掺入增加了Scn团簇的稳定性,使其能隙升高,并改变了其稳定性及电子结构性质随团簇尺寸变化的规律;含有偶数个Sc原子的氧化物团簇比其周围邻近的含有奇数个Sc原子的氧化物团簇具有相对较高的稳定性.ScnO团簇电离势的理论计算值与实验值符合得较好,而其电子亲和势呈现振荡交替上升的变化趋势;用最大化学硬度规律等方法表征了ScnO氧化物团簇的稳定性和电子结构性质.

The geometric structures, relative stability, electronic structure and their size dependence of scandium monoxide（ Scn O, n = 1-9） clusters are investigated by using density functional theory （DFr） at the BP86/CEP-121G level （the O atom treated with 6-311G^＊＊ basis sets）. With the cluster size increasing, the geometries of the lowest energy clusters show that the oxygen atom situated on the surface turn to be embed in the interior. The doped O atom enhances the stability, increases the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital and changes the trends of stability and electronic properties with the cluster size increasing. Results on even-odd oscillation in cluster stability and electronic properties predicted that the oxide clusters with even number of Sc atoms are more stable than the neighboring clusters with odd number of Sc atoms. The calculated vertical ionization energy values agreed especially well with the experimental values. The trend of electron affinities shows an obvious oseillatorg increasing behavior as the cluster size increasing. The stability and electronic structure of Sen O clusters are also characterized by the maximum hardness principle of chemical reactivity.