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运用广义梯度密度泛函理论(GGA)的Pcrdew-Burke-Emrnerh(PBE)方法结合团簇模型,在双数值极化函数基组DNP下,研究了(Fe_2O_3)_n(2≤n≤6)团簇的性质和NO在其上的吸附。对于(Fe_2O_3)_n团簇通过对几何构型和性质的计算发现;(Fe_2O_3)_n团簇都具有很高的稳定性并且它们的结构和成键性质都和体材料Fe_2O_3有很大的不同;NO主要以N端吸附在Fe_2O_3团簇Fe-top位。NO在(Fe_2O_3)_n团簇上吸附为化学吸附,对应于n从2~6,吸附能分别为1.792、1.976、2.799、2.963和2.536 eV。Mulliken布局分析结合NO吸附前后的态密度分析表明:吸附前后电子由NO向(Fe_2O_3)_n团簇转移,吸附时NO的5口轨道趋向于转移电子给Fd~(3+)的d轨道,使Fe位形成d~(10)稳定电子构型,同时Fe反馈电子给NO的知反键轨道,总体上为NO失去电子。
By using the Pcrdew-Burke-Emrnerh (PBE) method and the cluster model of generalized gradient density functional theory (GGA), the (Fe 2 O 3) _n (2≤n≤6) The nature of the cluster and the adsorption of NO on it. For the (Fe_2O_3) _n clusters, we found that the (Fe_2O_3) _n clusters have high stability and their structure and bonding properties are very different from that of the bulk material Fe_2O_3. NO mainly adsorbed on Fe-top of Fe_2O_3 cluster at N-terminal. NO was adsorbed on (Fe_2O_3) _n clusters as chemisorption, corresponding to n from 2 to 6, with adsorption energies of 1.792, 1.976, 2.799, 2.963 and 2.536 eV, respectively. The Mulliken layout analysis combined with the density of state before and after NO adsorption showed that the electron transfer from NO to (Fe_2O_3) _n clusters before and after adsorption, and the five orbits of NO tended to transfer electrons to the d orbit of Fd ~ (3+) Fe sites form d ~ (10) stable electronic configuration, while Fe feedback electron to NO known anti-bonding orbitals, the overall loss of electrons NO.