Theoretical Study On Structure And Properties Of Germanium Cluster Ge_n And Transition Metal Cu Doped Germanium Clusters CuGe_n

Germanium clusters have high electron mobility and hole mobility,and are widely used in the fields of photocatalytic materials,microelectronics,biological systems,environment and energy.Doping transition metal atoms in germanium clusters can change the thermodynamic and chemical stability of the clusters.The clusters can not only be used as structural units of assembled materials,but also can be multifunctional by changing the shape and size of the clusters.New materials provide important value for building environmentally friendly materials.In this paper,density functional theory is used to systematically study the ground state structure of thegermanium cluster Ge_n^0/-(n=4-14)and thetransition metal copper-doped germanium cluster CuGe_n^0/-(n=4-13),and calculate the adiabatic properties of the clusters Electron affinity energy,vertical electron dissociation energy,simulated photoelectron energy spectrum,atomization energy and HOMO-LUMO energy gap,through molecular orbital analysis and nuclear independent chemical shift method for the chemical bond analysis of the anion cluster CuGe^-₁₂.The mPW2PLYP/aug-cc-pVTZ//mPW2PLYP/cc-pVTZ method was used to systematically study the ground state configuration and physicochemical properties of the Ge_n(n=4-14)clusters.The research results show that:(1)The neutral ground state structure of the cluster Ge_n(n=4-14)is similar to the ground state structure of the anion,When n=8,the anionic cluster Ge₈^-has energy degeneracy and competes with each other for the ground state.(2)The simulated photoelectron spectroscopy Ge_n^-(n=4-14)is very consistent with the experimental photoelectron spectrum,indicating that the ground state structure of the anion is accurate and reliable.(3)The average bond energy analysis shows that the stability of anionic clusters is significantly higher than that of neutral clusters.The mPW2PLYP/aug-cc-pVTZ//mPW2PLYP/cc-pVTZ method was used to systematically study the ground state configuration and physicochemical properties of the small-sized CuGe_n^0/-(n=4-13)clusters.The research results show that:(1)For the ground state structure of the neutral CuGe_n(n=4-13)cluster,when n?8(except for n=4 and 7),the ground state structure is a Cu atom substituted for the ground state structure Ge_n+1Ge atom,when n?9,the ground state structure forms a cage structure,and the Cu atom is at the center of the germanium cage;for the ground state structure of the anion CuGe_n^-(n=4-13)cluster,when n?8,the ground state structure is a Cu atom replaces a Ge atom in the Ge_n+1cluster of the ground state structure.When n?9,the ground state structure forms a cage structure,and the Cu atom is embedded in the Ge^-_n+1cage structure.(2)The average bond energy analysis shows that the stability of anionic clusters is significantly higher than that of neutral clusters,and CuGe₁₂^-has the strongest stability.(3)Anion CuGe₁₂^-has high symmetry,excellent thermodynamic stability and chemical stability,and can become a building block for the construction of new multifunctional semiconductor materials.Comparing the properties of Ge_n^0/-(n=5-14)and CuGe_n^0/-(n=4-13)clusters,it is found that the introduction of transition metal Cu atoms into germanium clusters results in the thermodynamic stability of clusters CuGe₁₀^-and CuGe₁₂^-And the chemical stability is significantly improved,indicating that the introduction of transition metal Cu atoms in the germanium clusters has changed the properties,which provides more options for the construction of new multifunctional environmentally friendly materials.