John D. Weeks
MD twister


John Weeks Distinguished University Professor

Ph.D. University of Chicago, 1969
B.A. Harvard College, 1965

Joint Appointment with Institute for Physical Science and Technology and Department of Chemistry and Biochemistry

 Affiliate Professor: Department of Physics
 

Institute for Physical Science and Technology
University of Maryland
College Park, MD 20742-2021
phone (301) 405-4802 - fax (301) 314-9404
IPST  (Bldg. 085), Rm 1108 
jdw at umd.edu

 Teaching Spring 2014: Chem 687 Statistical Mechanics and Chemistry -- Syllabus

Awards

Fellow, American Physical Society, 1984
Distinguished Member of Technical Staff Award, Bell Laboratories, 1985
Joel Henry Hildebrand Award, American Chemical Society, 1990
Distinguished University Professor, University of Maryland, 1995 
Fellow, American Academy of Arts and Sciences, 2000 
Member, National Academy of Sciences, 2009 
Fellow, American Association for the Advancement of Science, 2012 

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Research in my group is concentrated in two main areas. The first focuses on the static and dynamic properties of interfaces, concentrating in particular on the dynamics of steps on crystal surfaces. This link describes new experiments and theory for the motion of a noncentered screw dislocation that is confined to the circular top facet of a nanoscale lead crystallite supported on a Ruthenium substrate. As shown in the movies these crystallites relax by turning of the spiral step emerging from the screw dislocation.

The figure at the right shows step bunches caused by the adsorption of impurities on crystal surfaces during crystal growth. Click on the following to see movies and learn more about instabilities and patterns that can form during step motion. This research is supported by the National Science Foundation through the Materials Research Science and Engineering Center (MRSEC) at Maryland. 

The second main area focuses on the properties of inhomogeneous and confined fluids, and is supported by the National Science Foundation. We have developed a new Local Molecular Field (LMF) theory of nonuniform liquids, initially based based on a physically motivated analysis of the different roles repulsive and attractive intermolecular forces play in determining liquid structure (i.e., the molecular scale arrangements of particles) in simple atomic liquids like Ar or Xe. This approach can be looked on as a modern and quantitative implementation of the ideas of van der Waals, who first showed the advantages of thinking about the different effects of attractive and repulsive forces. Click here for more information about this work.  

Our most recent research has focused on the conceptual and practical development of a general theory of nonuniform ionic and dipolar fluids (water in particular) based on a local molecular field (LMF) averaging of appropriately chosen slowly varying and long ranged components of the Coulomb interactions. The remaining short ranged components combine with the other short ranged molecular core interactions and strongly influence pair correlations between neighboring molecules in dense or strongly coupled fluid systems. The general theory can be viewed as a mapping that relates structure and thermodynamics in a nonuniform system with long ranged intermolecular interactions to those of a simpler mimic system, with short ranged intermolecular interactions but in a renormalized or effective single-particle molecular field that takes account of the averaged effects of the long-ranged interactions. In recent work we have shown that the theory takes on an especially simple and powerful form when it is applied to the basic Coulomb 1/r interaction alone (and not, e.g., to Lennard-Jones interactions as well). Click here for more information about this new work.  

Both these areas involve properties of strongly interacting disordered systems, and we use the same fundamental methods of statistical mechanics to try to develop general quantitative theories that make contact with experiment. While we use computer simulations to refine and test our ideas, the main emphasis is on the development of new conceptual approaches where physical insight and intuition play an important role.

Older hard-to-get review articles

H. C. Andersen, D. Chandler, and J. D. Weeks, "Roles of Repulsive and Attractive Forces in Liquids: The Equilibrium Theory of Classical Fluids," in Advances in Chemical Physics, Vol. 34, edited by I. Prigogine and S. A. Rice (Interscience, New York, 1976), pp. 105-154. 

J. D. Weeks and G. H. Gilmer, "Dynamics of Crystal Growth," in Advances in Chemical Physics, Vol. 40, edited by I. Prigogine and S. A. Rice (John Wiley, New York, 1979), pp. 157-228. 

J. D. Weeks, "The Roughening Transition," in Ordering in Strongly Fluctuating Condensed Matter Systems, edited by T. Riste (Plenum, New York, 1980), pp. 293-317. 

Recent Publications

Kandel, D. and Weeks, J.D., "Theory of Impurity Induced Step Bunching."  Phys. Rev. B 49, 5554-5564 (1994). 

Weeks, J.D., "Modeling Research." Comp. Mat. Sci. 2, 81-84 (1994). 

Kandel, D. and Weeks, J.D., "Step Motion, Patterns and Kinetic Instabilities on Crystal Surfaces." Phys. Rev. Lett. 72, 1678-1681 (1994). 

D. Kandel and J. D. Weeks, "Simultaneous Bunching and Debunching of Surface Steps: Theory and Relation to Experiments." Phys. Rev. Lett. 74, 3632-3635 (1995). 

J. D. Weeks, R. L. B. Selinger, and J. Q. Broughton, "Self-Consistent Treatment of Repulsive and Attractive Forces in Nonuniform Liquids."  Phys. Rev. Lett. 75, 2694-2697 (1995). 

D. Kandel and J. D. Weeks, "Kinetics of Surface Steps in the Presence of Impurities:  Patterns and Instabilities," Phys. Rev. B.  52, 2154-2164 (1995).

H.-C. Jeong and J. D. Weeks, "Faceting Through the Propagation of Nucleation.'' Phys. Rev. Lett. 75, 4456-4459 (1995). 

E. S. Fu, M. D. Johnson, D.-J. Liu, J. D. Weeks, and E. D. Williams, "Size Scaling in the Decay of Metastable Structures." Phys. Rev. Lett. 77, 1091-1094 (1996). 

D.-J. Liu, R. L. B. Selinger, and J. D.Weeks, "Representing Molecular Shape and Interactions: A Reduced Intermolecular Potential For Copper Phthalocyanine."
J. Chem. Phys. 105 , 4751-4760 (1996) . 

D.-J. Liu, E. S. Fu, M. D. Johnson, J. D.Weeks, and E. D. Williams, "Relaxation of the Step Profile for Different Microscopic Mechanisms."J. Vac.Sci. & Tech. B 14, 2799-2808 (1996). 

J.D. Weeks, D.-J. Liu, and H.-C. Jeong, "Two-Dimensional Models for Step Dynamics" in:  Dynamics of Crystal Surfaces and Interfaces, edited by P. Duxbuty and T. Spence (Plenum, New York) 1997, pp. 199-216. 

D.-J. Liu, J. D. Weeks, M. D. Johnson, and E. D.Williams, "Two-Dimensional Facet Nucleation and Growth on Si(111)." Phys. Rev. B 55, 7653-7659 (1997). 

J.D. Weeks, K. Vollmayr and K. Katsov, "Intermolecular Forces and the Structure of Uniform and Nonuniform Fluids." Physica A 244, 461-475 (1997). 

D.-J. Liu and J. D. Weeks, "Interactions between Fluctuating Steps on Vicinal Surfaces: Edge Energy Effects in Reconstruction Induced Faceting."
Phys. Rev. Lett. 79, 1694-1697 (1997). 

H.-C. Jeong and J. D. Weeks, "Two-Dimensional Dynamical Model for Step Bunching  and Pattern Formation Induced by Surface Reconstruction", Phys. Rev. B 57, 3939-3948  (1998).

D.-J. Liu and J. D. Weeks, "Quantitative Theory of Current-Induced Step Bunching on Si(111)." Phys. Rev. B 57 14891-14900 (1998).

D.-J. Liu, J. D. Weeks, and D. Kandel, "Current-Induced Step Bending Instability on Vicinal Surfaces", Phys. Rev Lett.  81, 2743-2746 (1998).

 J D. Weeks, K. Katsov, and K. Vollmayr, "Role of Repulsive and Attractive Forces in Determining the Structure of Nonuniform Liquids: Generalized Mean Field Theory", Phys. Rev. Lett.  81, 4400-4403 (1998).

K. Lum, D. Chandler and J. D. Weeks, "Hydrophobicity at Small and Large Length  Scales", J. Phys. Chem. B 103, 4570-4577 (1999).

H.-C. Jeong and J. D. Weeks, "Effect of Step-Step Interactions on the Fluctuations of an  Individual Step on a Vicinal Surface", Surf. Sci. 432, 101-114 (1999).

K. Thürmer, D-J. Liu, E. D. Williams, and J. D. Weeks, "Onset of Step Anti-Banding Instability due to Surface Electromigration",  Phys. Rev. Lett. 83, 5531-5534 (1999).

N. Israeli, H.-C. Jeong, D. Kandel, and J. D. Weeks, "Dynamics and Scaling of One Dimensional Surface Structures," Phys. Rev. B 61, 5698-5706 (2000).

K. Katsov and J. D. Weeks, "Determining Liquid Structure from the Tail of the Direct Correlation Function," J. Stat. Phys. 100, 107-134 (2000).

K. Vollmayr-Lee, K. Katsov, and J. D. Weeks, "Using Mean Field Theory to Determine the Structure of Uniform Fluids," J. Chem. Phys. 114, 416-425 (2001).

K. Katsov and J. D. Weeks, "Density Fluctuations and the Structure of a Nonuniform Hard Sphere Fluid," Phys. Rev. Lett.  86,  440-443 (2001).

K. Katsov and J. D. Weeks, "On the Mean Field Treatment of Attractive Interactions in Nonuniform Simple Fluids," J. Phys. Chem. B 105, 6738-6744 (2001).

J. D. Weeks, "Connecting Local Structure to Interface Formation: A Molecular Scale van der Waals Theory of Nonuniform Liquids," Annu. Rev. Phys. Chem. 53,  533-562 (2002).

J. D. Weeks, "External fields, Density Functionals, and the Gibbs Inequality," J. Stat. Phys. 110, 1209-1217 (2003).

K. Katsov and J. D. Weeks, "Incorporating Molecular Scale Structure into the van der Waals Theory of the Liquid-vapor Interface," J. Phys. Chem. 106,  8429-8436 (2002).

Y.-G. Chen and J. D. Weeks, "Different Thermodynamic Pathways to the Solvation Free Energy of a Spherical Cavity in a Hard Sphere Fluid," J. Chem. Phys. 118, 7944-7953 (2003)

J. D. Chai and J. D. Weeks, "Modified Statistical Treatment of Kinetic Energy in the Thomas-Fermi Model," J. Phys. Chem. B 108, 6870-6876 (2004).

T. Zhao, J. D. Weeks, and D. Kandel, "A Unified Treatment of Current-Induced Instabilities on Si Surfaces," Phys. Rev. B 70, 161303(R) 1-4 (2004).

T. Zhao, J. D. Weeks, and D. Kandel, "From Discrete Hopping to Continuum Modeling on Vicinal Surfaces with Applications to Si(001) Electromigration," Phys. Rev. B 71, 155326 1-9 (2005).

Y.-G. Chen, C. Kaur, and J. D. Weeks, "Connecting Systems with Short and Long Ranged Interactions: Local Molecular Field Theory for Ionic Fluids," J. Phys. Chem. B 108, 19874-19884 (2004).

T. Zhao and J. D. Weeks, "A Two-Region Diffusion Model for Current-Induced Instabilities of Step Patterns on Vicinal Si(111) Surfaces," Surface Science  580, 107-121 (2005).

Y.-G. Chen and J. D. Weeks, "Structure of Nonuniform Hard Sphere Fluids from Shifted Linear Truncations of Functional Expansions," J. Phys. Chem. B 109, 6892-6901 (2005).

M. Ranganathan, D. B. Dougherty, W. G. Cullen, T. Zhao, J. D. Weeks, and E. D. Williams, "Spiral Evolution in a Confined Geometry," Phys. Rev. Lett. 95, 225505/1-4 (2005).

Y.-G. Chen and J. D. Weeks, "Local Molecular Field Theory for Effective Attractions Between Like-charged Objects in Systems with Strong Coulomb Interactions," Proc. Natl. Acad. Sci. USA 103, 7560-7565 (2006).

J. C. Rodgers, C. Kaur, Y.-G. Chen and J. D. Weeks,"Attraction Between Like-Charged Walls:Short-Ranged Simulations Using Local Molecular Field Theory," Phys. Rev. Lett. 97, 097801/1-4 (2006).

J. -D. Chai and J. D. Weeks, "Orbital-Free Density Functional Theory: Kinetic Potentials and Ab Initio Local Pseudopotentials," Phys. Rev. B 75, 205122/1-14 (2007).

N. A. Denesyuk and J. D. Weeks, "A new approach for efficient simulation of Coulomb interactions in ionic fluids," J. Chem. Phys. 128, 124109/1-8 (2008).

C. Tao, Q. Liu, Blake S. Riddick, W. G. Cullen, J. Reutt-Robey, J. D. Weeks, and E. D. Williams, "Dynamic interfaces in an organic thin film," Proc. Natl. Acad. Sci. USA 105, 16418-16425 (2008).

J. M. Rodgers and J. D. Weeks, "Interplay of local hydrogen-bonding and long-ranged dipolar forces in simulations of confined water," Proc. Natl. Acad. Sci. USA 105, 19136-19141 (2008).

J. M. Rodgers and J. D. Weeks, "Local molecular field theory for the treatment of electrostatics," J. Phys-Cond. Matt. 20, 494206/1-11 (2008).

N. A. Denesyuk and J. D. Weeks, "Equilibrium and nonequilibrium effects in the collapse of a model polypeptide," Phys. Rev. Lett. 102, 108101/1-4 (2009).

B. J. Berne, J. D. Weeks and R. Zhou, "Dewetting and hydrophobic interaction in physical and biological systems," Annu. Rev. Phys. Chem. 60, 85–103 (2009).

J.-D. Chai, V. L. Lignères, G. Ho, E. A. Carter, and J. D. Weeks, "Orbital-Free Density Functional Theory: Linear Scaling Methods for Kinetic Potentials, and Applications to Solid Al and Si," Chem. Phys. Lett. 473, 263-267 (2009).

J.M. Rodgers and J. D. Weeks," Accurate thermodynamics for short-ranged truncations of Coulomb interactions in site-site molecular models," J. Chem. Phys. 131, 244108/1-8 (2009).

Z. Hu and J. D. Weeks,"Acetonitrile on Silica Surfaces and at Its Liquid-Vapor Interface: Structural Correlations and Collective Dynamics," J. Phys. Chem. C 114, 10202–10211 (2010).

Z. Hu and J. D. Weeks, "Efficient solutions of self-consistent mean field equations for dewetting and electrostatics in nonuniform liquids," Phys. Rev. Lett. 105, 140602 (2010).

F. Ding, Z. Hu, Q. Zhong, K. Manfred, R. R. Gattass, M. R. Brindza, J. T. Fourkas, R. A. Walker, and J. D. Weeks, "Interfacial Organization of Acetonitrile: Simulation and Experiment," J. Phys. Chem. C 114, 17651–17659 (2010).

J. M. Rodgers, Z. Hu, and J. D. Weeks, "On the efficient and accurate short-ranged simulations of uniform polar molecular liquids," Mol. Phys. 109, 1195–1211 (2011).

R. C. Remsing, J. M. Rodgers, and J. D. Weeks, "Deconstructing Classical Water Models at Interfaces and in Bulk," J. Stat. Phys. 145, 313–334 (2011).

S. Liu, Z. Hu, J. D. Weeks, and J. T. Fourkas, "Structure of Liquid Propionitrile at Interfaces. 1. Molecular Dynamics Simulations," J. Phys. Chem. C 116, 4012−4018 (2012).

M. Ranganathan and J. D. Weeks, "Theory of Impurity Induced Step Pinning and Recovery in Crystal Growth from Solutions," Phys. Rev. Lett. 110, 055503 (2013).

R. C. Remsing and J. D. Weeks, "Dissecting Hydrophobic Hydration and Association," J. Phys. Chem. B 117, 15479-15491 (2013).

D. Roy, S. Liu, B. L. Woods, A. R. Siler, J. T. Fourkas, J. D. Weeks and R. A. Walker, "Nonpolar Adsorption at the Silica/Methanol Interface: Surface Mediated Polarity and Solvent Density across a Strongly Associating Solid/Liquid Boundary," J. Phys. Chem. C 117, 27052−27061 (2013)


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