title: A threshold photoelectron-photoion coincidence spectrometer with double velocity imaging using synchrotron radiation.
abstract: A novel threshold photoelectron-photoion coincidence (TPEPICO) imaging spectrometer at the U14-A beamline of the Hefei National Synchrotron Radiation Laboratory is presented. A set of open electron and ion lenses are utilized to map velocity imaging of photoelectrons and photoions simultaneously, in which a repelling electric field using an extra lens is applied to magnify images of photoelectrons instead of traditional accelerating electric field in order to suppress the contribution of energetic electrons in the threshold photoelectron spectroscopy (TPES) and the mass-selected TPEPICO spectroscopy. The typical energy resolution of TPES is measured to be 9 meV (full width at half maximum), as shown on the (2)P(1/2) ionization of argon. The measured mass resolving power for the present TPEPICO imaging spectrometer is above 900 of M/DeltaM. Subsequently as a benchmark, oxygen molecule is photoionized by monochromatic synchrotron radiation at 20.298 eV and dissociates to an oxygen atomic ion and a neutral oxygen atom, and the translation energy distribution of oxygen atomic ion is measured by the time-sliced imaging based on mass-selected TPEPICO experiment. The kinetic energy resolution of the present ion velocity imaging is better than 3% of DeltaE/E.
authors: Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors: Xiaofeng
authors: X
authors: Tang
authors: Xiaoguo
authors: X
authors: Zhou
authors: Mingli
authors: M
authors: Niu
authors: Shilin
authors: S
authors: Liu
authors: Jinda
authors: J
authors: Sun
authors: Xiaobin
authors: X
authors: Shan
authors: Fuyi
authors: F
authors: Liu
authors: Liusi
authors: L
authors: Sheng
mesh_terms: D001128:Argon / Q000737:chemistry; D004583:Electrons; D013058:Mass Spectrometry; D010100:Oxygen / Q000737:chemistry; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy / Q000295:instrumentation* / Q000379:methods; D017356:Synchrotrons; D014978:Xenon / Q000737:chemistry
chemical_list: D014978:Xenon; D001128:Argon; D010100:Oxygen