Photoelectron Spectroscopic Studies On Mass Selected Cluster Anions In The Gas Phase

This thesis mainly introduces the design and construction of a home-built high-resolution photoelectron velocity map imaging setup,and its application on cluster studies combined with theoretical calculations.We probed a series of solvated anionic clusters by anion photoelectron spectroscopy,including the interaction between gold anions Au1,2~-and alcohol solvent molecules.Electronic structures,as well as the geometric and electronic structure of VO2H~-anion clusters were also studied.Besides,we studied the diatomic molecular anion clusters IO~-and ThC~-and their corresponding neutral molecules in ground and low-energy excited states.In addition,we combined the electrospray ion source technology,low-temperature ion trap technology,and double reflection time-of-flight mass spectrometry technology to design a new high-resolution cold anion slow electron velocity imaging that can be used to study coordinate metal complexes and multiple-charged anions.Small-sized gold nanoparticles and gold single atoms show high catalytic activity.In order to explore the nature of the interaction between solute-solvent molecules,(include the effects of different number of solvents and different solute ions)the Au1,2~-(Solv)n(Solv=C2H5OH,n-C3H7OH;n=1-3 for Au~-;n=1for Au2~-)were studied by anion photoelectron spectroscopy experiments combined with quantum chemical calculations.The change regularity of the structure was obtained and the estimation method for the binding energy of solvation was developed.It is interesting that the gold gauche effect similar to the case of fluorine was discovered,and to the best of our knowledge,this is the first gauche effect proposed for metal anions.Vanadium oxides play a pivotal role in heterogeneous catalysis,and bulk or supported vanadium oxides are used as catalysts in many industrial catalytic reactions for energy sustainability.We experimentally obtained the vibrational resolved photoelectron spectra of VO2H~-anion clusters.The electron affinity of the neutral VO2H and the vibrational frequency of the HO-V=O bending mode were assigned with the help of high-level theoretical calculations.We found that the electronic configuration of the VO2H~-system is similar to that of the VO2~-,and the V-O bond strength can be effectively weakened when H atoms combine with the O atom in VO2~-,which indicate that VO2H~-could exist as an intermediate product of VO2~-induced ethanol catalytic dehydrogenation.IO radical is catalyst for ozone-related photochemical reactions,Studying the photodissociation properties of IO radicals is essential to deepen the understanding of iodine photochemistry.In this thesis,the more accurate electron affinity and other spectral parameters of the IO molecule were determined by photoelectron imaging and photodetachment spectroscopy.We obtained accurate electron affinities and other spectral parameters of these two diatomic molecules using photoelectron imaging and high-precision calculations.For the IO~-anion,the theoretically predicted pre-dissociation state was verified,and a shallow bound excited state was observed,which is different from the repulsive characteristics predicted by theoretical calculations.Two interesting resonances were also observed,which were assigned as"dipole-induced resonances".The energy interval is similar to vibrational frequency of neutral IO molecule but significantly different from those caused by the dipole-bound state.ThC shows great potential to be considered as the next generation of nuclear fuel,while the spectroscopy of ThC molecule can provide valuable information to help for the development of actinide theoretical calculation.For ThC~-anion and its neutral ThC molecules,the experimental measurement results of the ground state and the first electronic excited state of neutral are in agreement with theoretical calculations,and their binding energy and vibrational frequencies are measured.It's worth noting that calculations of molecular orbitals and bond orders show that Th-C bonds are multiple bonds with covalent properties.Our home-built high-resolution photoelectron imaging can meet the needs of most of our research systems,however,the researches of some more complex systems and multiple-charged anion systems is still incapable.Therefore,we combined the electrospray ion source technology,low temperature ion trap technology and double reflection time-of-flight mass spectrometry technology to design a new high-resolution cold anion slow electron velocity imager with the ability to study complex systems and multiple-charged systems.