##
Senior Scientist: Computational Science

In 2009, Dr. Larsen joined the staff of NREL's Computational Science Center, where he uses electronic structure calculations and other theory and modeling to understand light absorption and charge dynamics in organic photovoltaic devices and disordered materials.

In his graduate research, Dr. Larsen worked with Dr. Richard M. Stratt on theories of short-time dynamics of liquids, focusing on the instantaneous normal mode approximation for liquid dynamics, and extending the theory to explain vibrational population relaxation in terms of transient pairing events in liquids.

After graduating in 1998, Dr. Larsen took a postdoctoral position working with Dr. Horia Metiu at the University of California, Santa Barbara, to work on computational near-field optics. In 2001, Dr. Larsen joined Dr. Benjamin J. Schwartz's research group at the University of California, Los Angeles (UCLA), where he used mixed quantum/classical molecular dynamics techniques to study excess charges and charge transfer processes in liquids, and where he developed new simulation algorithms for nonadiabatic dynamics. Dr. Larsen became a staff scientist at UCLA in 2006, and in 2007, he accepted a part-time lecturer position in the department of chemistry and biochemistry, where he taught introductory chemistry and physical chemistry.

## Research Interests

- Electronic structure and dynamics in the condensed phase
- Charge transport in the presence of mesoscale disorder
- Theory and modeling of organic photovoltaic devices
- Breakdown of the Born-Oppenheimer approximation and algorithms for nonadiabatic mixed quantum/classical molecular dynamics simulation
- Coupling of molecular electronic structure to electromagnetic fields.

## Education

1998 Ph.D., physics, Brown University

1996 M.S., physics, Brown University

1993 B.S., physics and Mathematics. University of Puget Sound.

## Selected Publications

- Larsen, R.E.; Glover, W.J.; Schwartz, B.J. (2010). "Does the Hydrated Electron Occupy a Cavity?."
(239); p. 65.*Science* - Glover, W.J.; Larsen, R.E.; Schwartz, B.J. (2010). "How Does a Solvent Affect Chemical Bonds? Mixed Quantum/Classical Simulations of Chemical Bond Dynamics with a Full CI Treatment of the Bonding Electrons."
(1); p. 165.*J. Phys. Chem. Lett.* - Glover, W.J.; Larsen, R.E.; Schwartz, B.J. (2008). "The Roles of Electronic Exchange and Correlation in Charge-transfer-to-solvent Dynamics: Many-electron Non-adiabatic Mixed Quantum/Classical Simulations of Photoexcited Sodium Anions in the Condensed Phase."
(129); p. 164505.*J. Chem. Phys.* - Larsen, R.E.; Bedard-Hearn, M.J.; Schwartz, B.J. (2006). "Exploring the Role of Decoherence in Condensed-phase Nonadiabatic Dynamics: Comparison of Different Mixed Quantum/Classical Simulation Algorithms for the Excited Hydrated Electron."
(B:110); p. 20055.*J. Phys. Chem.* - Larsen, R.E.; Schwartz, B.J. (2003). "Efficient Real-space Configuration-interaction Method for Simulation of Multi-electron Mixed Quantum/Classical Non-adiabatic Molecular Dynamics in the Condensed Phase."
(119); p. 7672.*J. Chem. Phys.*