Manini's research on fullerene

Fullerene C₆₀ is sometimes seen as a big molecule, sometimes as a small hollow cluster, sometimes as a graphene sheet wrapped up to a spherical shape. Strong C-C σ-bonding stabilize a rigid backbone structure. Substantially delocalized π electrons account for the chemical and optical properties of C₆₀. Below 800 K, C₆₀ forms a Van der Waals insulating solid of loosely bound individual molecules, which rotate almost freely down to approximately 260 K. Intercalation of alkali elements in C₆₀ can form ionic materials (fullerides), showing novel and exciting properties such as superconductivity, organic magnetism, correlated Mott-insulating states.

The hole wave function in one of the 5 degenerate HOMO orbitals.

• Coulomb repulsion among holes in C₆₀ fivefold degenerate last filled level (HOMO).
• Electron-phonon coupling in the positive and negative ions.
• The fullerene ions are exciting systems where several vibrational modes all coupled à la Jahn-Teller to a degenerate electronic state.
• In this electron-vibration coupling a Berry phase is often relevant.
• A successful calculation of the photoemission spectrum of the isolated molecule was carried out.

The distortion of the cation C₆₀⁺ (coloured) with respect to the uncharged ideal icosahedral configuration. The distortion is amplified by a factor 10 to make it visible.

A colorful picture of C₆₀. Distance modulates the color.