Electro-Fluidic Shuttle Memory Device: Classical Molecular Dynamics Study

We investigated the internal dynamics of several electro-fluid shuttle memory elements, consisting of several media encapsulated in C640 nanocapsule. The systems proposed were (i) bucky shuttle memory devices (C36+ @C420 and C60+ @C420), (ii) encapsulated-ions shuttle memory devices ((13+)@C420, (3+ -C60-2+ )@C640 and (5+ -C60)@C640) and (iii) endo-fullerenes shuttle memory devices ((K+ @C60- F-@C60)@C640). Energetics and operating responses of several electro-fluidic shuttle memory devices, such as transitions between the two states of the C640 capsule, were examined by classical molecular dynamics simulations of the shuttle media in the C640 capsule under the external force fields. The operating force fields for the stable operations of the shuttle memory device were investigated

Nanotube field and one-dimensional fluctuations of C 60 molecules in carbon nanotubes

C 60 molecules encapsulated in carbon nanotubes interact by van der Waals forces with the tube walls. The nanotube field leads to orientational confinement of the C 60 molecules which depends on the nanotube radius. In small tubes with radius R T≤7 Å a fivefold symmetry axis of the molecule coincides with the tube axis, the center of mass of the molecule being located on the tube axis. The interaction between C 60 molecules encapsulated in the nanotube is then described by a O 2-rotor model on a one-dimensional (1-d) liquid chain with coupling between orientational and displacive degrees of freedom but no long-range order. This coupling leads to a temperature-dependent chain contraction. The structure factor of the 1-d liquid is derived. In tubes with larger radius the molecular centers of mass are displaced off the tube axis. The distinction of two groups of peapods with on- and off-axis molecules suggests an explanation of the apparent splitting of A g modes of C 60 in nanotubes measured by resonant Raman scattering. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2005