Strong 3p -T1u Hybridization in Ar@C60

TL;DR

This study combines experimental photoemission spectroscopy and density functional theory to reveal strong hybridization between argon 3p orbitals and C60 molecular orbitals in Ar@C60, indicating a significant cage-atom interaction.

Contribution

It provides the first detailed experimental and theoretical evidence of strong 3p-6T1u hybridization in Ar@C60, characterizing it as a noble gas compound with notable cage coupling.

Findings

Hybridisation gap of 1.6 eV observed experimentally

DFT predicts a hybridisation gap of 1.47 eV

No giant Ar photoemission cross section detected

Abstract

Multilayers of fullerenes with and without endohedral Ar units, C60 and Ar@C60, were investigated by photoemission and density functional theory. The stoichiometry and the endohedral nature of Ar is checked by x-ray photoelectron spectroscopy and x-ray photoelectron diffraction. Valence band ultraviolet photoemission spectra show a strong hybridisation of the Ar 3p valence shell with the 6T1u molecular orbital of C60. A hybridisation gap of 1.6 +/- 0.2 eV is found. This is in agreement with density functional theory (DFT) that predicts 1.47 eV, and indicates Ar@C60 to be a noble gas compound with a strong coupling between Ar and the C60 cage. No giant Ar photoemission cross section as predicted for the gas phase in [Phys. Rev. Lett. 99, 243003 (2007)] was found.