David Chandler Seminar in Physical Chemistry: Dissecting direct and indirect intermolecular forces in simple and polar liquids

Seminar | April 17 | 4-5 p.m. | 120 Latimer Hall

 Prof. John Weeks, Institute for Physical Science and Technology and Department of Chemistry & Biochemistry, University of Maryland

 College of Chemistry

A characteristic feature of David Chandler's research was his ability to extend simple physical pictures and theoretical constructs in surprising new directions, often challenging conventional wisdom in the field. Here I mention three examples, all dealing with the interplay between strong short ranged intermolecular forces and more slowly varying long ranged van der Waals or Coulomb forces in equilibrium liquids. I first discuss the early work Chandler and I did with Hans Andersen, which builds on key ideas from van der Waals and Ben Widom, relating properties of a uniform Lennard Jones (LJ) liquid to those of a short ranged repulsive core reference system. Early in his academic career Chandler developed a new RISM theory describing the packing of more complicated molecular core shapes. In 1977 Chandler and Lawrence Pratt fearlessly extended some of those ideas to describe a much more difficult problem, the hydration and association of small hydrophobic LJ solutes in water, leading to the Pratt-Chandler (PC) theory of hydrophobicity. In the mid 1990's my group at Maryland began work on a more systematic treatment of the effects of long ranged Coulomb and van der Waals interactions in both uniform and nonuniform environments, called local molecular field (LMF) theory. During a memorable sabbatical leave at Berkeley in 1998, Chandler, Ka Lum, and I combined PC and LMF ideas to argue that interface formation around large hydrophobic solutes in water plays a key role in generating strong association forces. I will present qualitative and physically suggestive arguments for the accuracy of these generalizations, and discuss how working with David Chandler shaped this research and my approach to scientific research in general. New applications of LMF theory and further details of the theory will be presented tomorrow in the physical chemistry seminar.

 Light refreshments will be served at 3:50 at The Coffee Lab

 seminarcoordinator-cchem@berkeley.edu, 510-643-0572