Abstract:
A new theoretical approach for the prediction of the growth habit of
crystals is presented. This approach is
based on a newly derived relation between the growth rate of crystal
surfaces and habit-controlling factors,
and includes a key step: a so-called interface structure (IS) analysis.
This analysis is to formulate the influence
of the fluid phase on the crystal morphology. The essential of the
IS analysis is to identify the adsorbed growth
units which is in dynamic equilibrium with solid units at the crystal
surface, and to calculate their concentration.
It follows that a key external habit-controlling factor, the so-called
surface scaling factor, can be calculated
from the analysis. Based on detailed molecular dynamic (MD) simulation
data, our formalism is applied to
predict the morphology of urea crystals grown from aqueous solutions.
Urea crystals grown from the solutions
turn out to possess a needlelike shape, in excellent agreement with
experiments. This is one of the first
examples of the successful theoretical prediction of morphology of
crystals, and will provide a new way of
thinking and understanding of the influence of the mother phase on
crystal habits.