Dynamical Jahn-Teller effect of fullerene anions

Abstract

The dynamical Jahn-Teller effect of C${}_{60}^{n-}$ anions ($n=$ 1-5) is studied using the numerical diagonalization of the linear $p^n\otimes 8d$ Jahn-Teller Hamiltonian with the currently established coupling parameters. It is found that in all anions the Jahn-Teller effect stabilizes the low-spin states, resulting in the violation of Hund's rule. The energy gain due to the Jahn-Teller dynamics is found to be comparable to the static Jahn-Teller stabilization. The Jahn-Teller dynamics influences the thermodynamic properties via strong variation of the density of vibronic states with energy. Thus, the large vibronic entropy in the low-spin states enhances the effective spin gap of C${}_{60}^{3-}$ quenching the spin crossover. From the calculations of the effective spin gap in function of the Hund's rule coupling, we found that the latter should amount 40 $\pm$ 5 meV in order to cope with the violation of Hund's rule and to reproduce the large spin gap. With the obtained numerical solutions the matrix elements of electronic operators for the low-lying vibronic levels and the vibronic reduction factors are calculated for all anions.

15 pages + 3 pages

References in corpus (7)

• Dynamic Jahn-Teller effect in electron transport through single C60 molecules
• NMR study of the Mott transitions to superconductivity in the two Cs_3C_60 phases
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Cited by in corpus (7)

• Interplay between destructive quantum interference and symmetry-breaking phenomena in graphene quantum junctions
• Quadratic Jahn-Teller effect of fullerene anions
• Manifestation of vibronic dynamics in infrared spectra of Mott insulating fullerides
• Jahn-Teller effect in cubic fullerides A${}_3$C${}_{60}$
• Existence of a system of discrete volume-localized quantum levels for charged fullerenes
• Dynamical Jahn-Teller effect in the first excited C${}_{60}^{-}$
• First principles study of the vibronic coupling in positively charged C${}_{60}^{+}$