title: Structure and electronic properties of fullerenes C(52)q+: is C(52)2+ an exception to the pentagon adjacency penalty rule?
abstract: The structure, vibrational spectra and electronic properties of the neutral, singly and doubly charged C52 fullerenes were studied by means of the Hartree-Fock method and density functional theory. Different isomers were considered, in particular those with the lowest possible number (five or six) of adjacent pentagons, and an isomer with a four-atom ring. For neutral and singly charged species, the most stable isomer is that with the lowest number of adjacent pentagons, namely five. However, for C(52)2+, the most stable structure has six adjacent pentagons. This finding, which contradicts the pentagon adjacency penalty rule, is a consequence of complete filling of the HOMO pi shell and the near-perfect sphericity of the most stable isomer. The simulated vibrational spectra show important differences in the positions and intensities of the vibrations for the different isomers.
authors.affiliation: Departamento de Química, C-9, Universidad Autónoma de Madrid, 28049-Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Díaz-Tendero
authors.forename: Fernando
authors.initials: F
authors.lastname: Martín
authors.forename: Manuel
authors.initials: M
authors.lastname: Alcamí