## COMP 212 |

A theory for the line shape of molecular aggregates is formulated based on the reduced density matrix. Electronic coupling between the molecules is assumed to be weak. The spin-Boson model is introduced to include the effect of electron-phonon coupling. We derive kinetic equations for the reduced electronic density matrix associated with the absorption spectrum. General expressions of the time-dependent rate constants in the kinetic equations are derived by use of the cumulant expansion technique. The resulting time-dependent kinetic equations are solved numerically. We illustrate the applicability of the present theory by calculating the line shape of a dimer. |

Poster Session -- Sponsored by Novartis Institutes for BioMedical Research
6:00 PM-8:00 PM, Tuesday, 30 August 2005 Washington DC Convention Center -- Hall A, Poster
Division of Computers in Chemistry |