离子团簇YSi_(n)^(±)(n=7-16)的几何结构和电子性质的相对论密度泛函研究  

Relativistic density functional study on structures and electronic properties of YSi_(n)^(±)(n=7-16)ionic clusters

作　　者：杨阿平[1] 李东明[1] 田珊珊[2] 甄艳坤[1] 郭平 YANG A-Ping;LI Dong-Ming;TIAN Shan-Shan;ZHEN Yan-Kun;GUO Ping(School of Science,Xi’an Shiyou University,Xi’an 710065,China;School of Science,Xi'an University of Architecture and Technology,Xi’an 710055,China;Physics Department,Northwest University,Xi'an 710069,China)

机构地区：[1]西安石油大学理学院,西安710065 [2]西安建筑科技大学理学院,西安710055 [3]西北大学物理学院,西安710069

出　　处：《原子与分子物理学报》2023年第6期73-84,共12页Journal of Atomic and Molecular Physics

基　　金：陕西省重点研发计划项目(2018GY-062)。

摘　　要：运用广义梯度近似的相对论密度泛函理论方法对YSi_(n)^(±)(n=7-16)离子团簇的几何结构、稳定性和电子特性进行了系统地数值模拟研究.与中性YSi_(n)团簇比较可得到以下结论:除YSi 10+和YSi 13+阳离子团簇外,YSi_(n)^(±)团簇基本都保持了中性YSi_(n)团簇的结构框架,这与垂直和绝热电离能的结果本质上是一致的;大多数离子团簇的原子平均束缚能都相对中性团簇有明显增大,表明离子团簇的结构稳定性都有增强,其中阳离子团簇YSi_(n)+(n=8,11和14)和阴离子团簇YSi_(n)-(n=9,12和14)比其相邻团簇的稳定性更强.电荷布居分析表明所有团簇中Y原子的HC电荷都在n=15处由正值变为负值,即当Y原子从Si_(n)框架表面位点落入硅笼中形成内嵌结构团簇时,电荷转移方向发生反转.阴离子团簇中电荷转移量普遍减小,而阳离子团簇中普遍增大.HOMO-LUMO能隙结果表明离子团簇比其中性团簇的化学稳定性更强.The geometric structures,stabilities and electronic properties of YSi_(n)^(±)(n=7-16)clusters are systematically numerically simulated by using the relativistic density functional theory method of generalized gradient approximation.Compared with the neutral clusters,we can obtain conclusions:Except for YSi_(10)^(+) and YSi_(13)^(+) clusters,all YSi_(n)^(±) clusters basically maintain the structural framework of neutral YSi_(n) clusters,which is essentially consistent with the results of vertical and adiabatic ionization energies.The average atomic binding energies of most ionic clusters increase significantly,indicating that the structural stability of ionic clusters is enhanced,among which cationic clusters YSi_(n)^(+)(n=8,11 and 14)and anionic clusters YSi_(n)^(-)(n=9,12 and 14)are more stable than their neighboring clusters.Charge population analysis shows that the Hirshfeld charge(HC)of Y atoms change from positive to negative at n=15,i.e.,the direction of charge transfer is reversed when Y atoms fall from the surface sites into the silicon cages to form Y-embedded structures.The amount of charge transfer generally decreases in anion clusters,while it generally increases in cation clusters.The gaps between the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)results show that the ionic clusters are more chemically stable than their neutral clusters.

关 键 词：YSi_(n)^(±)(n=7-16)团簇 几何结构 稳定性 电荷布居 HOMO-LUMO能隙 

分 类 号：O561.1[理学—原子与分子物理]