Concentric-shell fullerenes and diamond particles: A molecular-dynamics study

Concentric-shell fullerenes are generated from diamond nanoparticles of 1.2 nm to 1.4 nm diameter by means of molecular dynamics simulations based on approximate Kohn-Sham equations. The diamond-to-concentric-shell fullerene transformation observed at temperatures from 1400 K to 2800 K starts at the surface of the diamond particle. Subsequently, the core of the particle gets disordered and the information about the initial atomic structure becomes lost. The final structure consists of two concentric graphitic shells. The intershell spacing of the generated concentric-shell fullerenes is distinctly below the interlayer distance of graphite. It is demonstrated that ${\mathrm{sp}}^3$-like cross links appear between the shells. Simulated irradiation accelerates the transformation but reduces the number of cross links.