Crystal-melt interfacial free energies of hard-dumbbell systems

The crystal-melt interfacial free energies of different crystal orientations and crystal forms for the hard-dumbbell systems have been calculated directly using a multistep thermodynamic perturbation method via nonequilibrium work measurements with a cleaving procedure. We found that for the plastic crystal phase, the interfacial free energies decrease as the reduced bond length L-* increases and the anisotropy is very weak as in isotropic systems. On the other hand, for the orientationally ordered crystal phase, the interfacial free energies become more than three times larger and the anisotropy is about 13%. These results may have significant implications for our understanding on the nucleation kinetics in molecular systems and the search of optimal conditions of protein crystallization.