Shake-up effects and intermolecular tunneling in C$_{60}$ ions

TL;DR

This paper investigates the electronic structure, Coulomb interactions, and optical properties of C$_{60}$ ions, highlighting how intermolecular effects influence their insulating behavior and tunneling phenomena.

Contribution

It provides a detailed analysis of multiplet structures, intramolecular repulsion, and the impact of intermolecular interactions on C$_{60}$ ions' electronic properties.

Findings

Large intramolecular repulsion (~1 eV) in C$_{60}^{n-}$

Significant probability of electronic excitation during electron addition/removal

Intermolecular interactions can suppress Coulomb repulsion, affecting insulating behavior

Abstract

The multiplet structure induced by the Coulomb interactions in C$_{60}^{n-}$ ($n = 1 - 12$) is analyzed. The partially ocuppied LUMO gives rise to a set of levels which fill a relatively wide band ( $\approx 2-3$ eV ). A large ($\sim 1$ eV) intramolecular effective repulsion is found. The anions are also shown to be highly polarizable. The optical absorption and photoemission spectra are calculated. The probability of exciting the molecule upon the addition or removal of one electron is shown to be significant, and this effect may give rise to the insulating behavior of K$_4$C$_{60}$. The role of intermolecular interactions in suppressing the net repulsion within the C$_{60}$ molecules is discussed.