Hund's rule magnetism in C60 ions?
International School for Advanced Studies (SISSA),
Via Beirut 4, 34014 Trieste, Italy
2 INFM Democritos National Simulation Center, and INFM, Unità Trieste, Italy
3 Daresbury Laboratory, Warrington WA4 4AD, UK
4 Dip. Fisica, Università di Milano, Via Celoria 16, 20133 Milano, Italy
5 INFM, Unità di Milano, Milano, Italy
6 International Centre for Theoretical Physics (ICTP), PO Box 586, 34014 Trieste, Italy
Corresponding author: a email@example.com
Published online: 22 September 2003
We investigate the occurrence of Hund's rule magnetism in C molecular ions, by computing the ground-state spin for all charge states n from -3 to +5. The two competing interactions, electron-vibration (e-v, including Jahn Teller, favoring low spin) and electron-electron (e-e, including Hund-rule exchange, favoring high spin), are accounted for based on previously computed ab initio coupling parameters. Treating the ion coordinates as classical, we first calculate and classify the static Jahn-Teller distorted states for all n, inclusive of both e-v and e-e effects. We then correct the adiabatic result by including the zero-point energy lowering associated with softening of vibrations at the adiabatic Jahn-Teller minima. Our overall result is that while, like in previous investigations, low-spin states prevail in negative ions, Hund's rule high spin dominates all positive C ions. This suggests also that Hund-rule magnetism could arise in fullerene cation-based solid state compounds, particularly those involving C.
PACS: 36.40.Cg – Electronic and magnetic properties of clusters / 61.48.+c – Fullerenes and fullerene-related materials (structure) / 71.20.Tx – Fullerenes and related materials; intercalation compounds (electronic structure) / 75.75.+a – Magnetic properties of nanostructures
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003