title: Slow-electron velocity-map imaging study of aniline via resonance-enhanced two-photon ionization method.
abstract: Slow electron velocity-map imaging (SEVI) of aniline has been investigated via two-color resonant-enhanced two-photo (1+1') ionization (2C-R2PI) method. A number of vibrational frequencies in the first excited state of neutral (S1) and2B1ground electronic state of cation (D0) have been accurately determined. In addition, photoelectron angular distributions (PADs) in the two-step transitions are presented and reveal a near threshold shape resonance in the ionization of aniline. The SEVI spectra taken via various S1intermediate states provide the detailed vibrational structures of D0state and directly deduce the accurate adiabatic ionization potential (IP) of 62,271±6cm-1. Ab initio calculations excellently reproduce the experimental IP value (Theo. 62,242cm-1). For most vibrational modes, good agreement between theoretical and experimental frequencies in the S0and D0states of aniline is obtained to aid us to clearly assign vibrational modes. Especially, the vibrational frequencies calculated at the CASSCF level are much better consistent with experimental data than that obtained using the TDDFT and CIS methods.
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Zehua
authors.initials: Z
authors.lastname: Qu
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China. Electronic address: asiake04@mail.ahnu.edu.cn.
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Qin
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China. Electronic address: xfzheng@mail.ahnu.edu.cn.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Guanxin
authors.initials: G
authors.lastname: Yao
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Xianyi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Cui
keywords: Aniline; Resonance-enhanced multiphoton ionization (REMPI); Time-of-flight; Velocity-map imaging