THE GROWTH OF EXTREMELY THIN-CRYSTALS - A MONTE-CARLO STUDY AND AN APPLICATION TO N-PARAFFINS

Monte Carlo simulations have been performed to investigate the growth and surface structures of the side faces of thin crystals and the top faces of needle-shaped crystals. The simulations have been used to inv estigate the effect of the width of the surfaces on their growth prope rties, such as the equilibrium point and the roughening temperature. B ecause of the Gibbs-Thomson effect the equilibrium point of small crys tal faces shifts towards higher supersaturations. This effect could be simulated very accurately and relations, describing the shift in equi librium, have been derived. The roughening temperature of very small c rystal faces depends also on their size. The roughening transition of crystal faces with different sizes has been investigated by the Monte Carlo technique and a simple analytical model to explain the increase in roughening temperature for decreasing crystal widths has been deriv ed. From an experimental point of view the Gibbs-Thomson effect has be en observed during the growth of thin n-paraffin crystals from differe nt solutions and quantitative measurements have been performed on thos e systems. The expressions derived from theory and Monte Carlo simulat ions have successfully been used to fit the experimental data and surf ace energies of the n-paraffin {0 0 1} faces are thus obtained. (C) 19 98 Elsevier Science B.V. All rights reserved.