Abstract
Single-wall carbon nanotubes (SWCNTs) are only moderately less stable than graphite, and are significantly more stable than their fullerene counterparts. They are 7 kJ•mol-1 metastable relative to graphite, and just 5 kJ•mol-1 less stable than diamond. Despite striking differences in vibrational dynamics of carbon atoms in SWCNTs and graphite, their thermodynamic properties at room and higher temperatures are dominated by the same set of high energy vibrations, reflected in very similar vibrational entropies. However, the energetics of SWCNT are governed by counter-acting enthalpic contributions of the diameter-dependent strain induced by the roll-up of graphene sheets into tubes and of carbon-carbon bonding at the edges of graphene sheets in the graphite, but not the specifics of phonon density of states (PDOS).
