Photoionization of Molecular Endohedrals

TL;DR

This paper calculates the photoionization cross-section of molecular endohedrals, specifically H2 inside fullerene, highlighting the effects of the fullerene shell and electron correlations on ionization behavior.

Contribution

It presents the first detailed comparison of photoionization in molecular versus atomic endohedrals, including correlation effects using RPAE.

Findings

Fullerene shell causes oscillations in photoionization cross-section.

Electron correlations significantly influence ionization results.

Molecular endohedrals show distinct features compared to atomic ones.

Abstract

We calculate the photoionization cross-section of a molecular endohedral. We limit ourselves to two-atomic molecules. The consideration is much more complex than for atomic endohedrals because the system even for almost spherical fullerenes has only cylindrical instead of spherical symmetry. On the other hand, molecular endohedral is more interesting since the interelectron interaction in molecules is relatively stronger than in similar atoms. We present here results of calculations of molecular hydrogen stuffed inside almost spherical fullerene. For comparison, we perform calculations also for atomic endohedral with Helium inside fullerene. The results are obtained both in the single-electron Hartree-Fock approximation and with account of multi-electron correlations in the frame of so-called random phase approximation with exchange. The presence of the fullerenes shell results in prominent oscillations in the endohedrals photoionization cross section. The role of interelectron correlations becomes clear by comparing HF and RPAE results for molecular and atomic endohedral on the one side with that for corresponding isolated molecule and atom on the other.