My research concerns the interpretation and prediction of novel dynamical behavior in isolated molecules.

Rydberg Spectroscopy of polyatomic molecules
Modern VUV and XUV high resolution laser studies of molecular Rydberg states raise new questions for theoretical spectroscopy. Interesting features include (i) breakdown of the BornOppenheimer approximation as the electronic energy separation becomes comparable even to rotational energy spacings, (ii) aoutoionization arising from inelastic scattering of the electron from the positive ion core, and (iii) new predissociation mechanisms. The aim is to develop a comprehensive theory of these diverse effects, by combining analytical and numerical scattering techniques. Recent work shows how ab initio methods can be extended to arbitrarily highly excited Rydberg states.

Semiclassical theories of complex intramolecular dynamics
Semiclassical methods aim to relate quantum mechanical observables to the underlying classical mechanics. Specific examples include early work on local mode states of small hydrides and interference effects on predissociation rates. More recently, similar methods indicate a characteristic pattern in quantum level structure at energies close saddle points on the potential surface– now taken as an example of socalled ‘quantum monodromy'.