Influence of caged noble-gas atom on the superatomic and valence states of C₆₀⁻

Abstract

Using high-level ab initio coupled cluster methods, we have conducted a detailed study of two endofullerene anions, He@C⁻₆₀ and Ne@C⁻₆₀. The main focus was on elucidating the effect of the noble-gas atom on the energy and electronic structure of the stable anion states of the parent C⁻₆₀. Our study revealed that the noble-gas atom has no influence on the valence-like states of C⁻₆₀, but strongly affects the superatomic-like ²A_g state. The latter was found to undergo pronounced destabilisation in both the He@C⁻₆₀ and Ne@C⁻₆₀ species, losing more than 70% of its original electron binding energy. The observed destabilisation is due to perturbation of the excess electron density of the ²A_g state inside the C₆₀ cage by the caged noble-gas atom. We show how the results of our analysis can be used to predict the behaviour of the ²A_g state in other closed-shell endohedral complexes. Some possible implications of the observed features of the ²A_g state are discussed.

Keywords:

• noble-gas C₆₀ endofullerenes
• anion states
• superatomic SAMO state
• electron affinity
• coupled cluster methods

Acknowledgements

Financial support of the Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged. We thank the high-performance computer centres of bwUniCluster funded by the Ministry of Science, Research and Arts and the Universities of the State of Baden-Württemberg, Germany, within the framework program bwHPC and Helics3a (Heidelberger Linux Cluster System, http://helics.uni-hd.de) for generously providing computational resources.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support of the Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged. We thank the high-performance computer centres of bwUniCluster funded by the Ministry of Science, Research and Arts and the Universities of the State of Baden-Württemberg, Germany, within the framework program bwHPC.