Eur. Phys. J. D (2013) 67: 51
https://doi.org/10.1140/epjd/e2013-30646-0

Regular Article

The role of the C₂ gas in the emergence of C₆₀ from the condensing carbon vapour

¹ Government College University (GCU), CASP, Church Road, 54000 Lahore, Pakistan
² Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad, Pakistan

^a e-mail: sahmad.ncp@gmail.com

Received: 20 October 2012
Received in final form: 19 December 2012
Published online: 19 March 2013

Abstract

A model has been developed that illustrates C₆₀’s emergence from the condensing carbon vapour. It is shown to depend upon (i) the decreasing heats of formation for larger cages; (ii) exponentially increasing number of isomers for fullerenes that are larger than C₆₀; (iii) large cages’ buckling induced by the pentagon-related protrusions that initiate fragmentation; (iv) the structural instability-induced fragmentation that shrinks large cages via C_x → C_x−2 + C₂; and (v) an evolving gas of C₂ that is crucial to the whole process. The model describes a mechanism for the provision and presence of plenty of C₂s during the formation and fragmentation processes. Fullerenes portrayed as 3D rotors have partition functions describing ensemble’s entropy as a function of the fragmentation sequence. The bottom-up formations of large cages followed by the top-down cage shrinkage are shown to be stable, dynamical processes that lead to the C₆₀ dominated fullerene ensemble.