title: Quantum chemical study of atomic structure evolution of Cox/C60 (x<or=2.8) composites.
abstract: The main features of the local atomic structure of novel Cox/C60 (x<or=2.8) complex mixtures were studied using the ab initio B3LYP/6-31G* method for a set of low- and high-energy Con(C60)m (n=1, 2, m=2, 3) clusters in low and intermediate spin states. For the n = 1 isomers the spin state S=1/2 is energetically preferable, whereas the low-energy isomers of n=2 have an intermediate spin state of S=1. The eta2 (6-6 edge of C60) type of cobalt ion coordination is preferable for both the n=1 and n=2 cases. The eta2' (coordination with a 6-5 edge) and even the eta5 (C5 fragment) types can serve as low- and high-energy intermediates for the cobalt ion's migration around the C60 cage. Formation of cobalt dimers can be the final stage of evolution of Cox/C60 atomic structure approaching the equilibrium atomic geometry.
authors: Takasaki-Branch, Advanced Science Research Center, Japan Atomic Energy Agency, Takasaki, 370-1292, Japan. avramov.pavel@jaea.go.jp
authors: Pavel
authors: P
authors: Avramov
authors: Hiroshi
authors: H
authors: Naramoto
authors: Seiji
authors: S
authors: Sakai
authors: Kazumasa
authors: K
authors: Narumi
authors: Vasily
authors: V
authors: Lavrentiev
authors: Yoshihito
authors: Y
authors: Maeda