This program computes emission and absorption spectra for molecular systems with multiple chromophores where nearly degenerate excited states cause coupling between electronic and vibrational degrees of freedom. The original theory for symmetric bichromophores was created by Witkowski and Moffitt  and expanded on by Fulton and Gouterman . Many applications of this theory to various gas phase multi-chromophore complexes exist in the literature .
Three major alterations have been made to the theory from its original form. The theory in this implementation can now handle systems with an arbitrary number of chromophores, allowing for potentially much larger systems to be simulated. Since many such larger systems lack true symmetry, the model has also been extended to allow for slight asymmetries between the monomer units, which can manifest themselves in the inter-chromophore electronic coupling constants, electronic excitation energies, or vibrational Hamiltonian. Finally, an optional inter-monomer vibrational mode Hamiltonian has been added to the system, allowing for the simulation of vibrational modes that change the coupling constants between the chromophores, usually by altering their spacing or orientation. The included PDF manual has more details on running the program, as well as how these changes are implemented.
Current published work using this program include simulations of diphenylmethane and asymmetrically deuterated diphenylmethane. See the 'Publications' section for details.
The program is currently written in Matlab and has a graphical user interface (GUI) for easy use.
Creation of this program was funded by:
Summer Faculty Fellowship Program in conjunction with the Air Force Research Laboratory, Aerospace Systems Directorate
National Science Foundation, grant CHE-0955419
Purdue Purdue Research Foundation
Andrews Graduate Fellowship
 A. Witkowski, W. Moffitt, "Electronic Spectra of Dimers: Derivation of the Fundamental Vibronic Equation" J. Chem. Phys. 33, 872-875 (1960).
 R. L. Fulton, M. Gouterman, "Vibronic Coupling. I. Mathematical Treatment for Two Electronic States" J. Chem. Phys. 35, 1059 (1961).
 P. Ottiger, S. Leutwyler, H. Koppel "S1/S2 Excitonic Splittings and Vibronic Coupling in the Excited State of the Jet-cooled 2-aminopyridine Dimer" J. Chem. Phys. 131, 204308 (2009).
Cite this work
Researchers should cite this work as follows:
B. Nebgen, F. L. Emmert, L. V. Slipchenko, "Vibronic coupling in asymmetric bichromophores: Theory and application to Diphenylmethane" J. Chem. Phys. 137, 084112 (2012).