Structural Evolution And Superatomic Properties Of Transition Metal Doped Boron Clusters

Boron clusters have peculiar electronic structure,bonding characteristics and aromatic properties,which make them a research hotspot in the field of cluster science.They are rich in structure and can be widely used in the fields of optics,energy,medical treatment and storage of industrial gases.The transition metal atom doping is an effective way to stabilize the cluster structure and tailor the electronic properties.By adjusting the chemical bond and energy level occupation,the cluster will attain desirable structures and properties,which greatly enriches the relevant scientific theories and shows great potential application value.Therefore,the determination of the ground state structure is very important for the study of bond cooperation between metal atoms and boron ligands.In this paper,the transition metal doped boron clusters have been theoretically studied by the first-principles method,and the growth pattern and physicochemical characteristics of the structure are analyzed.Using the genetic algorithm program?CGA?based on the density functional theory,we searched the lowest energy structure of molybdenum doped medium-sized boron cluster MoB_n?n=10,12,14,16,18,20,22,24?,and showed the structural evolution mode from bowl structure to tube structure and then to package cage structure.By calculating the average binding energy per atom,HOMO-LUMO gap,vertical ionization potential and vertical electron affinity of the system,it is found that MoB₁₂,MoB₂₂ and MoB₂₄ have higher stability than the other clusters.In order to explore the origin of cluster stability,we drew the molecular orbital energy level diagram,according to the electron occupation and orbital shape,we finally concluded that the MoB₂₂ packaging cage satisfies the 18-electron rule and is a closed shell superatomic cluster.In order to study the doping effect of transition metal atoms on boron clusters more systematically,we conducted a high-throughput search for TMB_n?n=7-10?of small boron clusters with 4d and 5d transition metals?TMs?as dopants.Different from the quasi-planar structure of pure boron clusters,when doped with metal atoms,the lowest energy structure includes:bowl,quasi-planar,wheel,umbrella and irregular vertebral body,which greatly enriches the types of cluster structures.Through relative stability calculation,it is found that RhB₇,IrB₇,RuB₈,OsB₈,IrB₉,AgB₉ and AuB₉ clusters are highly stable and belong to superatomic clusters.This is because the system has 12 delocalized electrons to satisfy the two-dimensional disc-shaped jellium model.At the same time,according to the results of the AdNDP analysis,the above cluster systems contain three delocalized?bonds and three delocalized?bonds,which meet the 4n+2 Hückel rule and have dual aromaticity.