Optical Absorption in Higher Fullerenes: Effects of Symmetry Reduction

TL;DR

This paper calculates and analyzes the optical absorption spectra of higher fullerenes C70 and C76, revealing how symmetry reduction affects spectral features and optical gaps, with results aligning well with experimental data.

Contribution

It introduces a tight binding model with long-range Coulomb interactions to accurately predict optical spectra of higher fullerenes, highlighting effects of symmetry reduction.

Findings

Optical gap decreases with symmetry reduction from C60 to C76

Spectra show more small structures as symmetry reduces

Calculated spectra agree with experimental results

Abstract

Optical absorption spectra of higher fullerenes (C70 and C76) as well as of C60 are calculated by a tight binding model with a long range Coulomb interaction. A reasonable parameter set gives calculated spectra which are in overall agreement with the experiments of of C60 and C76 in solutions. The variations of the spectral shape are discussed relating with the symmetry reduction going from C60 and C70 to C76: the optical gap decreases and the spectra have more small structures in the dependences on the excitation energy. Keywords: optical absorption, fullerene, C60, C70, C76, CI calculation, theory