Photoelectron Velocity Imaging Study Of Transition Element Oxide Clusters

Transition metal oxides are widely used as catalysts in industrial processes,such as oxidation,ammoxidation and dehydrogenation reactions.lanthanide oxides have attracted widespread attention for their potential applications in information storage,catalysts,catalyst support,optics,colorants for special glasses and so on,due to their unique electronic properties.In this thesis,several typically cluster anions RhOn-(n=1-3)and HoO-in the gas phase have been systematically studied using a time-of-flight(TOF)mass spectrometer and a photoelectron velocity-map imaging(VMI)instrument.Combining photoelectron imaging spectroscopy with quantum chemical calculations,the geometric structure,electronic properties and chemical bonding of MOn(n=1-3,M=Rh,Ho)have been studied.This study can help us to understand the chemical bonding in M-containing(M=Rh,Ho)molecules and will provide some light in their surface chemistry,catalysis and photochemistry investigation.The main research contents are as follows:(1)Combining the photoelectron velocity-map imaging spectroscopy and FranckCondon simulation,the adiabatic detachment energy(ADE),vertical detachment energy(VDE)and vibration frequency of MOn-(M=Rh,Ho,n=1-3)clusters were determined.(2)Based on density functional theory(DFT),the neutral and anionic clusters of MOn(M=Rh,Ho,n=1-3)were studied,and the most stable cluster structures were obtained.(3)Through quantum chemistry calculations,the theoretical ADEs and VDEs values of the anionic MOn(M=Rh,Ho,n=1-3)clusters were obtained with Gaussian 16 software.Based on the generalized Koopmans' theorem(GKT),the VDEs of higher energy states can be estimated by adding an energy correction term to the eigenvalue of the orbital energy level of negative ions.Hence,we calculated the VDE values of higher energy states and simulated the photoelectron spectroscopy(PES)of the corresponding clusters.The experimental spectra and the simulated spectra showed good agreement.(4)Based on the natural bond orbital(NBO)method,we used the natural atomic orbital(NAO)analysis to study the orbital composition and the chemical bonding process of anionic clusters.Relevant research can deepen our understanding of the chemical bonding of transition elements,and can effectively screen ligands through the differences of covalent.