DYNAMICS AT THE NONEQUILIBRIUM CRYSTAL-MELT INTERFACE.

The nonequilibrium interface separating a crystal of salol growing into its undercooled melt has been investigated by quasielastic laser light scattering spectroscopy. Observations on the a and b faces revealed that during crystal growth, two distinct dynamical processes occur simultaneously. With the laser beam incident from the crystal side of the interface and polarized for total internal reflection, the scattering is highly anisotropic and the scattered light is Doppler-shifted by an amount proportional to the scattering vector q. Preliminary evidence for relaxational scattering during crystal growth has also been obtained for the non-faceting low alpha -factor material cyclohexanol. The origin of the relaxational scattering remains uncertain. Several models that have been proposed to explain it are reviewed. Refs.