Coordination-resolved Bond And Electron Spectrometrics Of The Nanomaterials Rb,Cs And Ta

Since the discovery of nano materials,it has attracted scientists from all over the world to explore the study.In recent years,solid surfaces and nanoclusters are the hot spots due to their excellent physical and chemical properties,such as elastic modulus,melting temperature,magnetic properties,catalytic properties,and some properties that bulk material never reflected.We need a model that the low-coordination atom as the research center and the bond–order–length–strength(BOLS)notion as the core idea,to explain these anomalous features.In this paper,we show that the interaction between undercoordinated atoms of the chemically active Rb and Cs perturbs the local Hamiltonian that dictates the electronic behaviour of these two elements universally.In addition,we also correlate core level binding energy(BE)with the cluster size and shape with the aid of density functional theory(DFT)calculations and X-ray photoelectron spectroscopy(XPS)measurements.Results confirmed our predictions that atomic undercoordination shortens and stiffens bonds in the skins and atomic clusters,which dictates the unusual behavior of solid skins and atomic clusters.The detailed work and results achieved are as follows:(i)We systematically examined the effect of atomic undercoordination on the performance of bonds and electrons of Rb and Cs atomic clusters and their solid skins using a combination of photoelectron spectrometric analysis and density functional theory calculations.Consistency between predictions and observations revealed that the Rb 4p level shifts from 13.654 e V for an isolated atom to a bulk value of 14.940 eV and the Cs 5p level shifts from 10.284 to 11.830 eV upon bulk formation.The atomic coordination number reduction shortens the bonds by up to 30% for the Rb13 and Cs13 clusters,which densifies the local electrons and entraps their binding energies.(ii)Based on the bond–band–barrier(3B)correlation and ZPS method,we analyzed the oxidation of Ta surface.Due to the bond formation,the O atoms squeeze the top layer because of the O-Ta bonds are much stronger than the Ta-Ta bonds,and cause some Ta atoms to be moved from their original sites,which results the surface reconstruction.Moreover,results showed the essentiality for the formation of O-Ta bond with four additional DOS features: bonding electron pairs,nonbonding lone pairs,holes,and antibonding dipoles.