Quantum and classical features of the photoionization spectrum of C$_{60}$

TL;DR

This paper analyzes the photoionization spectrum of C60 fullerene, distinguishing quantum and classical effects, and links spectral features to specific excitations and molecular orbitals using ab initio and model approaches.

Contribution

It provides a detailed mapping of spectral features to physical phenomena, highlighting the quantum origins of certain peaks amidst plasmon excitations.

Findings

Spectral features linked to single-particle and collective excitations.

Quantum origin of peaks atop plasmon excitations.

Discrete transitions and orbital ionizations identified.

Abstract

By considering photoionization of the C$_{60}$ fullerene, we elucidate the contributions of various classical and quantum physics phenomena appearing in this process. By comparing the results, based on the {\it ab initio} and model approaches, we map the well-resolved features of the photoabsoprtion spectrum to single-particle and collective excitations which have the different physical nature. It is demonstrated that the peculiarities arising in the photoionization spectrum of C$_{60}$ atop the dominating plasmon excitations have the quantum origin. In particular, we demonstrate that a series of individual peaks can be assigned either to the optically allowed discrete transitions or to ionization of particular molecular orbitals of the system. The analysis performed gives a detailed information on the nature of numerous features in the photoabsorption spectrum of C$_{60}$.