Hyperfine structure of Sc@C82 from ESR and DFT

TL;DR

This study combines ESR and DFT to analyze the hyperfine structure of Sc@C82, revealing anisotropic tensors, a partly covalent bond, and electron spin distribution primarily on the cage with some on scandium.

Contribution

It provides a detailed analysis of the hyperfine and g-tensors of Sc@C82, linking their principal axes to molecular orientation and elucidating the nature of the Sc-cage bond.

Findings

g-tensor is anisotropic and not axially symmetric

Most electron spin density is on the carbon cage

Scandium d_yz orbital contributes to anisotropy

Abstract

The electron spin g- and hyperfine tensors of the endohedral metallofullerene Sc@C82 are anisotropic. Using electron spin resonance (ESR) and density functional theory (DFT), we can relate their principal axes to the coordinate frame of the molecule, finding that the g-tensor is not axially symmetric. The Sc bond with the cage is partly covalent and partly ionic. Most of the electron spin density is distributed around the carbon cage, but 5% is associated with the scandium d_yz orbital, and this drives the observed anisotropy.