30 research outputs found
Formation of a "Cluster Molecule" (C20)2 and its thermal stability
The possible formation of a "cluster molecule" (C20)2 from two single C20
fullerenes is studied by the tight-binding method. Several (C20)2 isomers in
which C20 fullerenes are bound by strong covalent forces and retain their
identity are found; actually, these C20 fullerenes play the role of "atoms" in
the "cluster molecule". The so-called open-[2+2] isomer has a minimum energy.
Its formation path and thermal stability at T = 2000 - 4000 K are analyzed in
detail. This isomer loses its molecular structure due to either the decay of
one of C20 fullerenes or the coalescence of two C20 fullerenes into a C40
cluster. The energy barriers for the metastable open-[2+2] configuration are
calculated to be U = 2 - 5 eV.Comment: 21 pages, 8 figure
Stability of C20 fullerene chains
The stability of (C20)N chains with N = 3 - 7 is analyzed by numerical
simulation using a tight-binding potential and molecular dynamics. Various
channels of losing the cluster-chain structure of the (C20)N complexes are
observed, including the decay of C20 clusters, their coalescence, and the
separation of one C20 fullerene from the chain.Comment: To appear in JETP Letter
Structure and Stability of Two-Dimensional Complexes of C_20 Fullerenes
Two-dimensional complexes of C_20 fullerenes connected to each other by
covalent bonds have been studied. Several isomers with different types of
intercluster bonds have been revealed. The lifetimes of the (C_20)_MxM systems
with M = 2 and 3 have been directly calculated at T = 1800 - 3300 K making use
of molecular dynamics. It has been shown that these complexes lose their
periodic cluster structure due to either coalescence of two fullerenes C_20 or
decay of C_20 fullerenes. The activation energies of these processes exceed 2
eV.Comment: 17 pages, 5 figure