Raymond Kapral

Many chemical systems can be partitioned into a subsystem whose dynamics must be treated quantum mechanically and into an environment which may be accurately treated by classical mechanics.  Such open quantum systems arise in numerous contexts; for example, for proton and electron transfer processes in chemical and biological systems.  Theoretical approaches are being developed to study the quantum dynamics and quantum statistical mechanics of such systems, especially in regimes where the environment can induce transitions among the quantum degrees of freedom.  Methods are being developed to simulate the dynamics of many-body quantum-classical systems and applications are being made to quantum rate processes in bulk condensed phases, micelles, clusters and biological systems. 

When studying the dynamics of solute molecules in the condensed phase using molecular dynamics, the need to simulate the motions of many solvent molecules often limits the type of system that can be investigated. Research in this area is concerned with the construction of mesoscopic models for molecular dynamics that allow one to bridge space and time scales and simulate large complex systems. Applications to nano-clusters, reactive processes and biomolecule dynamics in solution are being carried out.

The macroscopic dynamics of systems constrained to lie far from equilibrium can be very rich, ranging from simple steady states to complex oscillatory or chaotic motion. Physical systems of this type are common in nature and the observed phenomena include fluid and chemical turbulence, instabilities in lasers and nonlinear optical devices and periodic and aperiodic behaviour in biological systems like the heart and nerve tissue. Chemical systems provide good examples for the study of such phenomena. One of the main thrusts of current research in this area in the interplay between space and time in nonlinear dynamical systems. A variety of techniques in nonlinear dynamical systems theory are being applied to the study of macroscopic and microscopic models for dynamics of these systems.