团簇FePS_(3)的电子性质及反应活性密度泛函研究

Density functional study on the electronic properties and reactivity of the FePS_(3) cluster

以团簇FePS_(3)为局域模型,在B3LYP/def2-tzvp水平下采用Gaussian 09程序对团簇FePS_(3)进行结构优化及虚频验证,获得12种稳态构型,分析了这12种构型的原子电荷量、电子自旋密度及反应活性。结果表明:团簇FePS_(3)中S原子为电子受体,Fe、P原子为电子供体,Fe比P原子更容易失去电子,团簇FePS_(3)整体的电子流向为从Fe、P原子流入S原子;Fe、P原子间和Fe、S原子间的过剩电子主要为自旋向下的β成单电子,P、S原子间和S、S原子间的过剩电子主要为自旋向上的α成单电子;构型4(4)、2(2)、1(2)、2(4)、1(4)和4(2)的电子自旋密度的对称性最好,稳定性最高,因此这6种构型可能为团簇FePS_(3)的优势构型;构型6(2)的前线轨道(HOMO-LUMO)能隙差最小,最容易发生电子跃迁,反应活性最高;构型2(4)的HOMO-LUMO轨道能隙差最大,反应活性最低。

Using the cluster FePS_(3) as the local model,structure optimization and imaginary frequency verification were carried out using the Gaussian 09 program at the B3LYP/def2-tzvp level,and 12 steady-state configurations were obtained.The atomic charges,electron spin densities and reactivities of these 12 configurations were analyzed.The results show that the S atom in the FePS_(3) cluster is an electron acceptor,and the Fe and P atoms are electron donors.Fe atoms are more likely to lose electrons than P atoms.The overall direction of electron flow in the FePS_(3) cluster is from Fe and P to S atoms.The excess electrons between Fe and P atoms and between Fe and S atoms are mainly spin-downβ-single electrons,and the excess electrons between P and S atoms and between S and S atoms are mainly spin-upα-single electrons.The electron spin densities of configurations 4(4),2(2),1(2),2(4),1(4)and 4(2)have the best symmetry and the highest stability.Hence these six configurations may be the dominant configurations of the FePS_(3) cluster.The frontier orbital(HOMO-LUMO)energy gap of configuration 6(2)is the smallest,which is,therefore,most prone to electron transitions and has the highest reactivity.The HOMO-LUMO orbital energy gap of configuration 2(4)is the largest and this configuration has the lowest reactivity.