Calculation of the crystal-melt interfacial free energy of succinonitrile from molecular simulation

The crystal-metal interfacial free energy for a six-site model of succinonitrile [N C-(CH2)(2)-C N] has been calculated using molecular-dynamics simulation from the power spectrum of capillary fluctuations in interface position. The orientationally averaged magnitude of the interfacial free energy is determined to be (7.0 +/- 0.4)x10(-3) J m(-2). This value is in agreement (within the error bars) with the experimental value [(7.9 +/- 0.8)x10(-3) J m(-2)] of Marasli [J. Cryst. Growth 247, 613 (2003)], but is about 20% lower than the earlier experimental value [(8.9 +/- 0.5)x10(-3) J m(-2)] obtained by Schaefer [Philos. Mag. 32, 725 (1975)]. In agreement with the experiment, the calculated anisotropy of the interfacial free energy of this body-centered-cubic material is small. In addition, the Turnbull coefficient from our simulation is also in agreement with the experiment. This work demonstrates that the capillary fluctuation method of Hoyt [Phys. Rev. Lett. 86, 5530 (2001)] can be successfully applied to determine the crystal-melt interfacial free energy of molecular materials. (c) 2006 American Institute of Physics.