Research Interests
 Protein nucleation and crystal growth
 Nonlinear diffusion
 Theory of Nucleation
 Zeolites
 Crystallization
 Bubble Cavitation and Sonoluminescence
 Reactive flows far from equilibrium
 Structure of nonequilibrium fluids
 Granular Fluids
 Nonextensive statistical mechanics
 Fuzzy rule induction
Publications
Useful Links
American Physical Society
American Institute of Physics
Materials Research Society
Info
Cirriculum Vitae
Email: jlutsko AT ulb.ac.be
Address:
Center for Nonlinear Phenomena and Complex Systems
University Libre de Bruxelles
Campus Plaine, CP 231, 1050 Bruxelles, Belgium

2variable extension of classical nucleation theory.
A twovariable stochastic model for diffusionlimited nucleation is developed using a formalism derived from fluctuating hydrodynamics. The model is a direct generalization of the standard Classical Nucleation Theory. The nucleation rate and pathway are calculated in the weaknoise approximation and are shown to be in good agreement with direct numerical simulations for the weaksolution/strongsolution transition in globular proteins. We find that Classical Nucleation Theory underestimates the time needed for the formation of a critical cluster by two orders of magnitude and that this discrepancy is due to the more complex dynamics of the two variable model and not, as often is assumed, a result of errors in the estimation of the free energy barrier. Read more...


Free energy surfaces as functions of radius and density of a cluster. Left: subcritical, Right: supercritical  the line shows the most likely nucleation pathway.



The physical basis of step pinning.
The growth of crystals from solution is a fundamental process of relevance to such diverse areas as Xraydiffraction structural determination
and the role of mineralization in living organisms. A key factor determining the dynamics of crystallization is the effect of impurities on step growth.
For over fifty years, all discussions of impuritystep interaction have been framed in the context of the CabreraVermilyea (CV) model for step blocking,
which has nevertheless proven difficult to validate experimentally. Here we report on extensive computer simulations which clearly falsify the CV model,
suggesting a more complex picture. While reducing to the CV result in certain limits, our approach is more widely applicable, encompassing nontrivial impuritycrystal interactions,
mobile impurities and negative growth, among others. More soon ...


Left: Snapshot of kineic Monte Carlo simulation. Right: Step velocity shown as size of circles as a function of impurity size, L, and impurity spaceing, n_{c} shown for three different supersaturations. Blue indicates positive velocity, red is negative velocity and white is statistically zero. The CV prediction for zero velocity is everything below the broken line marked CV.

APS  AIP  MRS
