Molecular dynamics study of orientational melting and thermodynamic properties of C-60@C-240 nanoparticles

The barriers to relative shell rotation and other energy characteristics of C-60@C-240 two-shell carbon nanoparticles (onions) with outer shells of different shapes are calculated. The disturbance of the orientational order in the mutual arrangement of shells with an increase in temperature (orientational melting) is studied by the molecular dynamics method. The intershell orientational diffusion is represented by the Arrhenius relationship, and the Arrhenius parameters are calculated numerically. A definition is proposed for the temperature of short-range order disturbance in systems that undergo melting without structural change. The calculated temperature of orientational melting of the C-60@C-240 nanoparticle is approximately equal to 60 K. (C) 2002 MAIK Nauka/Interperiodica.