Home Page of Jim Lutsko

Last updated: Sept. 22, 2014

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
2-variable extension of classical nucleation theory.
A two-variable stochastic model for diffusion-limited 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 weak-noise approximation and are shown to be in good agreement with direct numerical simulations for the weak-solution/strong-solution 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: sub-critical, Right: super-critical - 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 X-ray-diffraction 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 impurity-step interaction have been framed in the context of the Cabrera--Vermilyea (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 non-trivial impurity-crystal interactions, mobile impurities and negative growth, among others. Read the paper... view movies
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.

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