Conformation-Selective Resonant Photoelectron Spectroscopy via Dipole-Bound States of Cold Anions.
Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap. We observed two conformers of cold 3-hydroxyphenoxide anions [m-HO(C6H4)O(-)] in high-resolution photoelectron spectroscopy and measured different electron affinities, 18,850(8) and 18,917(5) cm(-1), for the syn and anti 3-hydroxyphenoxy radicals, respectively. We also observed dipole-bound excited states for m-HO(C6H4)O(-) with different binding energies for the two conformers due to the different dipole moments of the corresponding 3-hydroxyphenoxy radicals. Excitations to selected vibrational levels of the dipole-bound states result in conformation-selective photoelectron spectra. This method should be applicable to conformation-selective spectroscopic studies of any anions with dipolar neutral cores.
†Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
Dao-Ling
DL
Huang
‡Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Hong-Tao
HT
Liu
§Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.
Chuan-Gang
CG
Ning
†Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
Lai-Sheng
LS
Wang
D000838:Anions / Q000737:chemistry; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry; D008968:Molecular Conformation; D056951:Photoelectron Spectroscopy; D012118:Resorcinols / Q000737:chemistry*; D013816:Thermodynamics
D000838:Anions; D005609:Free Radicals; D012118:Resorcinols; C031389:resorcinol
dipole-bound state; molecular conformation; photoelectron spectroscopy