Theory of Spontaneous Polarization of Endohedral Fullerenes

TL;DR

This paper develops a theoretical model to understand how endohedral fullerenes can spontaneously break symmetry due to atom distortions, identifying a critical coupling strength for this transition.

Contribution

It introduces a pseudo-Jahn-Teller model specifically for endohedral fullerenes, providing insights into their polarization behavior and symmetry-breaking mechanisms.

Findings

Identifies a critical coupling constant for symmetry breaking.

Provides vibronic parameters for specific endohedral fullerenes.

Predicts conditions under which inversion symmetry is broken.

Abstract

A pseudo-Jahn-Teller model describing central atom distortions is proposed for endohedral fullerenes of the form A@C$_{60}$ where A is either a rare gas or a metal atom. A critical (dimensionless) coupling $g_c$ is found, below which the symmetric configuration is stable and above which inversion symmetry is broken. Vibronic parameters are given for selected endohedral fullerenes.