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Center for Nonlinear Studies |
The behavior of excited states in finite systems and their interactions with phonons is of great importance to modern day material research, and has spawned many methods for simulation. From light harvesting to photochemistry, the behavior of excitons these interactions appear in many applications, and understanding these behaviors is critical. When one seeks to simulate the behavior of excited states in such systems one must first decide on a time dependent or time independent approach, with each method having pros and cons. This talk will explore recent methodological developments and applications regarding both of these approaches. The time independent method explored here is a generalized version of Köppel, Domcke, and Cederbaum’s method of building Hamiltonians for symmetric bichromophores. By using a raising and lowering operator formalism, the method has been expanded to asymmetric systems. This method is then applied to a series of asymmetrical bichromophores and excellent agreement is obtained with jet cooled spectroscopy obtained by Zwier and co-workers. The time dependent method explored is the joining of Fewest Switches Surface Hopping with the Fragment Molecular Orbital (FMO) method to permit the simulation of larger molecular systems efficiently. This method is then applied to both a Fe(CO)4 undergoing radiationless decay in solution, which is an ideal candidate as solvents are very well described by the FMO method. Additionally, energy and electron transfer between fragments is explored in an application to donor chromophore acceptor trials. If you would like to meet with Ben, please contact Sergei Tretiak (serg@lanl.gov)
Host: Sergei Tretiak