Frenkel and charge transfer excitons in C60

TL;DR

This study uses momentum-dependent electron energy-loss spectroscopy to analyze low-energy electronic excitations in C60, determining the energy of specific excitons and clarifying their nature as Frenkel or charge transfer types.

Contribution

It provides the first direct experimental measurement of the 1Hg excitation energy and distinguishes the excitons' nature in C60.

Findings

Determined the energy of the 1Hg excitation.

Elucidated the nature of excitations as Frenkel or charge transfer.

Measured the total width of the multiplet from the gap transition.

Abstract

We have studied the low energy electronic excitations of C60 using momentum dependent electron energy-loss spectroscopy in transmission. The momentum dependent intensity of the gap excitation allows the first direct experimental determination of the energy of the 1Hg excitation and thus also of the total width of the multiplet resulting from the gap transition. In addition, we could elucidate the nature of the following excitations - as either Frenkel or charge transfer excitons.