# Vibronic coupling in C$_{60}^-$ anion revisited: Precise derivations from photoelectron spectra and DFT calculations

## TL;DR

This study revises the vibronic coupling constants of C$_{60}^-$ using high-resolution photoelectron spectra and DFT calculations, finding weaker couplings than previously reported and resolving earlier discrepancies between theory and experiment.

## Contribution

The paper provides a more accurate derivation of vibronic coupling constants for C$_{60}^-$, reducing previous overestimations and aligning theoretical calculations with experimental data.

## Key findings

- Weaker Jahn-Teller mode couplings than earlier reports.
- 30% reduction in total stabilization energy.
- DFT calculations agree with revised experimental constants.

## Abstract

The vibronic coupling constants of C$_{60}^-$ are derived from the photoelectron spectrum measured by Wang {\it et al}. [X. B. Wang, H. K. Woo, and L. S. Wang, J. Chem. Phys., {\bf 123}, 051106 (2005).] at low temperature with high-resolutions. We find that the couplings of the Jahn-Teller modes of C$_{60}^-$ are weaker than the couplings reported by Gunnarsson {\it et al}. [O. Gunnarsson, H. Handschuh, P. S. Bechthold, B. Kessler, G. Gantef{\"{o}}r, and W. Eberhardt, Phys. Rev. Lett., {\bf 74}, 1875 (1995).]. The total stabilization energy after $h_g$ and $a_g$ modes is reduced with respect to the previous derivation of Gunnarsson {\it et al}. by 30 \%. The computed vibronic coupling constants using DFT 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.