Educational Background:

DPhil, Oxford University, 1980 BA, Oxford University, 1976

Awards:

• Alfred P. Sloan Research Foundation Fellow • Camille and Henry Dreyfus Teacher-Scholar Award • International Academy of Quantum Molecular Science Medal

Research Description:

Our research is concerned with the bound state and reaction dynamics of molecular and atomic systems. Processes of interest include intramolecular vibrational energy transfer, unimolecular dissociation, and the interaction of molecules with strong external fields. Classical trajectory methods, semiclassical theories, and direct solution of the nuclear Schrodinger equation are employed as appropriate to investigate fundamental problems in intramolecular and collision dynamics.

A central aim of our work is a detailed understanding of intramolecular energy flow and its consequences for spectroscopy and chemical kinetics. In particular, we seek chemically useful correlations between the shape of a molecular potential energy surface and the associated reactive and bound-state dynamics. Another basic theme of our work is the relation between the classical and quantum mechanics of systems of chemical interest such as molecular Hamiltonians or multielectron atoms.

Although remarkable progress continues in the quantum mechanical treatment of molecular systems, the study of the classical and semiclassical mechanics of molecules is justified on both practical and conceptual grounds. The conceptual advantages of a classical visualization of mechanisms for chemical reactions and intramolecular energy transfer inferred from trajectory calculations are obvious and well established. Moreover, special kinds of classical motions (periodic orbits) have been found to play an increasingly important role in providing a framework for understanding phenomena such as excited vibrational states of molecules and doubly excited states of two-electron atoms. The importance of classical periodic orbits is founded in recent developments in the general semiclassical theory of chaotic systems. Semiclassical methods enable quantum mechanical quantities such as energy levels or optical response functions to be computed, in many cases very accurately, using only classical mechanics.

Problems currently under investigation include the kinetics of rupture of polymer chains under stress, the semiclassical theory of response of atomic and molecular systems to external perturbations, the interaction of molecular rotors with strong external fields, and the dynamics of non-Hamiltonian systems.

For further information, see Dr. Ezra's research page.

Selected Publications:

G. S. Ezra, "On the statistical mechanics of non-Hamiltonian systems: the generalized Liouville equation, entropy, and time-dependent metrics", J. Math. Chem. 35, 29-53 (2004).

W. G. Noid, G. S. Ezra, and R. F. Loring, "Optical response functions with semiclassical dynamics", J. Chem. Phys. 119 , 1003-1020 (2003).

C. A. Arango, W. W. Kennerly, and G. S. Ezra, "Quantum and classical mechanics of diatomic molecules in tilted fields", J. Chem. Phys. 122, 184303 (2005).

G. S. Ezra, "Reversible measure-preserving integrators for non-Hamiltonian systems", J. Chem. Phys.125, Art. No. 34104 (2006).

S. A. Deshpande and G. S. Ezra, "Quantum state reconstruction for rigid rotors", Phys. Rev. A, submitted.

A full list of publications can be found here.