  We present a classical molecular-dynamics study of the collective dynamical
properties of the coexisting liquid phase at equilibrium body-centered cubic
(BCC) Fe crystal-melt interfaces. For the three interfacial orientations (100),
(110), and (111), the collective dynamics are characterized through the
calculation of the intermediate scattering functions, dynamical structure
factors and density relaxation times in a sequential local region of interest.
An anisotropic speed up of the collective dynamics in all three BCC
crystal-melt interfacial orientations is observed. This trend differs
significantly different from the previously observed slowing down of the local
collective dynamics at the liquid-vapor interface [Acta Mater 2020;198:281].
Examining the interfacial density relaxation times, we revisit the validity of
the recently developed time-dependent Ginzburg-Landau (TDGL) theory for the
solidification crystal-melt interface kinetic coefficients, resulting in
excellent agreement with both the magnitude and the kinetic anisotropy of the
CMI kinetic coefficients measured from the non-equilibrium MD simulations
