|Similarity Transformations Applied to Vibronic Coupling Models|
| Christopher Leon, Marcel Nooijen|
|Department of Chemistry|
University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Non-adiabatic effects in molecules which arise from the interaction between electronic and nuclear degrees of freedom can be modelled with a vibronic Hamiltonian. The matrix representation of multistate-multimode vibronic coupling models scales exponentially with the number of vibrational quanta in each mode. This renders the problem computationally expensive even for small molecules. To circumvent this problem, an indirect approach involving second quantization and similarity transformations is used. Some preliminary results are discussed.