UC Berkeley

This thesis is concerned with tractable methods for modeling the optical and electronic properties of photosynthetic light harvesting complexes. We begin by investigating the validity of the commonly used Frenkel Exciton Hamiltonian, and find that it is inaccurate at the intermolecular distances commonly encountered in photosynthetic systems. We introduce semi-empirical tight-binding Hamiltonians and dynamics models that are better able to simulate the electronic properties of these chromophores at the proper distances and orientations. These models are validated by comparisons of the predictions to experimental results.