Theoretical Study On The Structural Evolution And Electronic Properties Of Ir-doped B Clusters

Due to its large specific surface area and exceptionally high chemical and catalytic activity,clusters have a wide range of applications in many aspects.The basic problem of cluster science is to clarify the changes in the structure and properties of clusters in the process of evolving into macroscopic solid matter.Since many physical and chemical properties of clusters are determined by the structure of clusters,finding the most stable structure of clusters is the primary problem in studying clusters.Due to the lack of electrons,boron clusters are easy to share electrons to form multi-center bonds.Their special structure and chemical properties have attracted people's attention.Transition metal-doped boron clusters provide an unusual bonding method and provide a new way for the design of boron-based nanomaterials.Based on the above reasons,we systematically studied the structural evolution and electronic properties of the neutral and anionic iridium-doped boron clusters IrBn0/-(n=10-20),The main content and final results of this work are as follows:(1)Through the CALYPSO cluster structure prediction method,the neutral and anionic IrBn0/-(n=10-20)clusters were searched for the structure,and then combined with density functional theory,the structure of the obtained clusters was optimized.The results show that the ground state structures of IrBn and IrBn-clusters tend to form plane and quasi-planar structures when the size is small,and as the size increases,most of them show cage-like and drum-like structures.It is worth noting that the ground state structure of IrB18-is a planar boroene structure,which is expected to become a feasible sequence of metallo borophenes.(2)Through theoretical research,the photoelectron spectra of anionic IrBn-is simulated,and its vertical detachment energy is obtained.The theoretical value of IrB18-is compared with the experimental value of transition metal-doped boron clusters of the same main group.The results show that there are two isomers in the spectrum to compete for the global minimum,which means that the quasi-planar structure with Cs symmetry and the drum-like structure with D9d symmetry can coexist in the IrB18cluster.(3)By calculating the binding energy,se ond-order differential energy and HOMO-LUMO gaps of the ground state structure of the iridium-doped boron clusters,it is found that the clusters with an even number of boron atoms in the negative are relatively more stable than the adjacent clusters.(4)Natural population analysis(NPA)was used to understand the distribution of negative charges in the ground state structure of Ir-doped B clusters.It was found that the amount of charge on Ir atoms in most anion clusters was higher than the amount of charge on Ir in the corresponding neutral clusters,which may be due to Ir It is more electronegative and more likely to get a negative charge.(5)Chemical bond analysis shows that the quasi-planar structure of IrB18clusters is aromatic with 10? electrons.The strong interaction between the 2p orbitals of the peripheral B atoms and the 5d orbitals of the metal Ir atoms enhances the stability of the anion IrB18-clusters.The current findings provide new insights into the structural evolution of Ir-doped B clusters of different sizes,and open the way for the design of metal borophenes.