Nonequilibrium quantum chemical molecular dynamics simulations of C60 to SiC heterofullerene conversion

Abstract

Nonequilibrium high-temperature quantum chemical molecular dynamics simulations based on the self-consistent-charge density-functional tight-binding (DFTB) method for the conversion of C60 to SiC fullerene by way of periodic Si atom supply are presented. Random supply of Si atoms on the surface of a perfect Ih-C60 buckminsterfullerene without simultaneous carbon atom removal merely leads to formation of an exohedrally adsorbed Si cluster during the entire length of our simulations via an Ostwald ripening process, whereas supply of Si atoms in combination with simultaneous carbon atom removal affords the formation of SiC fullerene structures up to a lower limit of 2:1 for the C:Si ratio. Our simulations demonstrate the importance of vacancy defects for atomic substitution-based approaches for heterofullerene cages, and hint at inherent difficulties of such approaches for the actual synthesis of hypothetical, idealized sp2-hybridized SiC nanostructures with a 1:1 ratio featuring fully alternating atomic structures and no Si–Si and C–C bonds.