Photoelectron Spectroscopy of Singly and Doubly Charged Higher Fullerenes at Low Temperatures: C76-, C78-, C84- and C76(2-), C78(2-), C84(2-)
Photoelectron spectroscopy of vibrationally cold singly and doubly charged higher fullerenes, Cn– and Cn2– (n = 76, 78, and 84), has been investigated at several photon energies. Vibrationally resolved spectra are obtained for both the singly and doubly charged species and for n = 78 and 84 transitions from different isomers are also observed. The electron affinities (EA’s) of C76, C78, and C84 are accurately determined to be 2.975±0.010 eV for C76, 3.20±0.01 eV for C78(C2v), 3.165±0.010 eV for C78(D3), 3.23±0.02 for C78(C2v’), 3.185±0.010 eV for C84(D2), and 3.26±0.02 eV for C84(D2d). The second EA’s of the higher fullerenes, which represent the electronic stability of the doubly charged anions, are measured to be 0.325±0.010 eV for C76, 0.44±0.02 eV for C78(C2v), 0.53±0.02 eV for C78(D3), 0.60±0.04 eV for C78(C2v’), 0.615±0.010 eV for C84(D2d), and 0.82±0.01 eV for C84(D2). The spectra of the dianions are observed to be similar to that of the singly charged anions, suggesting that the charging induces relatively small structural changes to the fullerene cages. The onsite Coulomb repulsions in the doubly charged fullerenes are directly measured from the differences of the first and second EA’s and reveal strong correlation effects between the two extra electrons. The repulsive Coulomb barriers in the doubly charged fullerenes are estimated from the cutoff in the photoelectron spectra and are found to be consistent with estimates from an electrostatic model.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 927719
- Report Number(s):
- PNNL-SA-55132; 3170a; KP1704020; TRN: US0804797
- Journal Information:
- Journal of Physical Chemistry C, 111(48):17684-17689, Vol. 111, Issue 48
- Country of Publication:
- United States
- Language:
- English
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