RESEARCH INTERESTS
Our research deals with theoretical and computational aspects of molecular and
materials sciences, with emphasis on the unified treatment of physical and
chemical kinetics using quantum molecular dynamics. It includes
collision-induced and photoinduced phenomena in the gas phase, clusters, and
at
solid surfaces. Our aim is to provide a fundamental approach to
molecular dynamics, where electronic and nuclear motions are consistently
coupled to account for quantal effects. We use quantum and statistical
mechanics, mathematical, and computational methods, to describe time-dependent
phenomena (such as femtosecond dynamics and spectra) in both simple and
complex molecular systems.
In particular:
Quantum molecular dynamics.
- Energy transfer, electron transfer and reactions in gas phase molecular
collisions.
- Energy transfer, electron transfer and reactions of molecules at solid
surfaces.
- Intermolecular forces in ground and excited electronic states.
- Spectra and dynamics in atomic clusters.
- Photodissociation of polyatomic molecules.
- Photodesorption of molecules from solid surfaces.
- Light emission in collisions of ions with atoms and solid surfaces.
Theoretical methods.
- Time-dependent many-electron theory; time-dependent molecular orbital and
time-dependent Hartree-Fock approaches to molecular phenomena.
- Few-body and many-body theory of molecular collisions; collisional
time-correlation approach to many-atom collisions.
- Statistical mechanics of response and rate processes.
- Density matrix theory of relaxation, dissipation and fluctuations in
extended molecular systems.
Computational methods.
- Numerical methods for the solution of differential and integral equations
of scattering.
- Variational methods for scattering and time-dependent states.
- Path integral and wavepacket propagation in quantum dynamics.
- Constrained simulated annealing and constrained molecular dynamics.
- Operator algebra methods for solving operator differential equations.
- Numerical methods for the solution of the Liouville-von Neumann
differential equation for the density operator.
- Integration of stochastic differential equations for coupled quantal and
classical degrees of freedom, and of the generalized Langevin equations.
- Integration of differential equations for coupled fast and slow degrees of
freedom. The "relax-and-drive" method.
- Calculation of molecular one- and two-electron
integrals for travelling atomic basis functions.
Computer visualization and animation of molecular interactions.
- Animation of the temporal evolution of both nuclear motions and electronic
densities using nuclear trajectories and isocontours of electronic
densities.
- Animation of electronic transitions and electron transfer obtained from
time-dependent molecular orbitals.
- Animation of light emission in collisions of ions involving electronic
rearrangement and the related transient dipoles.