Vibronic coupling in ${\text{C}}_{60}^{-}$ anion revisited: Derivations from photoelectron spectra and DFT calculations

The vibronic coupling constants of ${\text{C}}_{60}^{-}$ are derived from the photoelectron spectrum measured by Wang et al. [J. Chem. Phys. 123, 051106 (2005)] at low temperature with high resolutions. We find that the couplings of the Jahn-Teller modes of ${\text{C}}_{60}^{-}$ are weaker than the couplings reported by Gunnarsson et al. [Phys. Rev. Lett. 74, 1875 (1995)]. The total stabilization energy after $h_g$ and $a_g$ modes is reduced with respect to the previous derivation of Gunnarsson et al. by 30%. The computed vibronic coupling constants using density-functional theory with B3LYP functional agree well with the new experimental constants, so the discrepancy between theory and experiment persistent in the previous studies is basically solved.

Figure 1

(Color online) The photoelectron spectrum measured by Wang et al. (black line) and the simulated spectrum (red line). The simulation is performed at 70 K with $\sigma =80{\text{cm}}^{-1}$.

Figure 2

(Color online) The peak of the photoelectron spectra due to $a_g\left(2\right)$, $h_g\left(7\right)$, and $h_g\left(8\right)$ modes. The black line indicates the experimental spectrum of Wang et al. (Ref. 15), the red line indicates the simulated spectrum, and the blue line indicates the difference between the experimental and simulated spectra. The top of the two spectra is simulated using the VCCs (1) and the bottom one is simulated using the VCCs (3) from Table . The simulation is performed at 70 K with $N=6$ and $\sigma =80{\text{cm}}^{-1}$.

Figure 3

(Color online) The experimental photoelectron spectrum measured by Gunnarsson et al. (Ref. 3) (black line) and the simulated spectrum (red line). The simulation is performed at 200 K with $\sigma =120{\text{cm}}^{-1}$.