Faculty Research
Alphabetical · By research area

The main focus of our research is to study the quantum dynamics and statistical mechanics of systems of interest in physical chemistry. Our efforts are aimed towards a better understanding of vibrational, reorganization and reaction dynamics in systems where quantum mechanical effects such as zero-point energy and tunneling are important. To achieve this understanding, we devote a considerable portion of these efforts to the development of efficient computational methods for the simulation of quantum systems. We are interested in both exact and approximate formulations and employ a variety of techniques such as Feynman path integral Monte Carlo simulations, molecular dynamics, mixed quantum/classical and grid-based methods. Quantities such as finite temperature time correlation functions, transport coefficients, and spectra can be computed and compared to experiment. Central to any of these calculations is a potential energy surface which describes the interactions between particles in the system, and the development of such potential energy surfaces is also of interest to our group.

The following projects are currently underway:

• Path integral Monte Carlo simulations of superfluid helium dynamics.
• Dynamical studies of molecular species embedded in helium droplets.
• Simulation of photoelectron spectra of hydrogen-bonded dimers.

This research program offers the opportunity to be involved in a diverse range of areas of theoretical chemistry. Students are exposed to the latest techniques in high performance computing (including parallel programming) enabling them to develop both modeling and simulation expertise as well as general scientific programming skills.

Selected Publications

Y. Huh and P.-N. Roy, "Inclusion of inversion symmetry in centroid molecular dynamics: A possible avenue to recover quantum coherence", J. Chem. Phys. 125, 164103 (2006).

J. E. Cuervo and P.-N. Roy, "Path integral ground state study of finite size systems: Application to small (para-hydrogen)N (N = 2-20) clusters", J. Chem. Phys. 125, 124314 (2006).

M.P. Nightingale and P.-N. Roy, "Excited states of weakly-bound bosonic clusters: discrete variable representation and quantum Monte Carlo", J. Phys. Chem. A 110, 5391 (2006).

Y. Xu, N. Blinov, W. Jäger, and P.-N. Roy, "Recurrences in rotational dynamics and experimental measurement of superfluidity in doped helium clusters", J. Chem. Phys. 124, 081101 (2006).

B. B. Issack and P.-N. Roy, "Geometric constraints in semiclassical initial value representation calculations in Cartesian coordinates: accurate reduction in zero point energy", J. Chem. Phys. 123, 084103 (2005).

P.-N. Roy, "Energy levels and wavefunctions of weakly-bound bosonic trimers using Pekeris coordinates and a symmetry-adapted Lanczos approach", J. Chem. Phys. 119, 5437 (2003).