Multiplet Structures of Charged Fullerenes

TL;DR

This paper calculates the multiplet splittings of charged fullerene ions using the CAS SCF method, providing detailed parameters for the intramolecular Hamiltonian and comparing results with other computational approaches.

Contribution

It introduces a CAS SCF-based approach that accurately treats symmetry and provides new parameters for modeling charged fullerenes, improving upon previous methods.

Findings

Coulomb parameter U ≈ 3.1 eV for electrons and 3.2 eV for holes

Hund's rule exchange parameter J ≈ 113 meV for electrons and 192 meV for holes

Comparison with LDA, MNDO, and model SCF methods

Abstract

We calculated multiplet splittings for positively and negatively charged fullerene ions within the CAS SCF method, and extracted model parameters for the intramolecular Hamiltonian. The method treats correctly the symmetry of ground and excited states for partially occupied degenerate molecular orbitals. We compare our results to previous calculations by the LDA, MNDO and model SCF methods. The multiplet averaged Coulomb parameter U is about 3.1 eV for electrons and 3.2 eV for holes. The Hund's rule exchange parameter J is found to be 113 meV for electrons and 192 meV for holes.