Inhomogeneous broadening of electronic spectra in organic model systems

We studied the inhomogeneous broadening of the electronic transitions of the linear polyene octatetraene doped into mixed crystal matrices of various n-alkanes with added halogenated alkanes. The additional broadening caused by the halogenated alkane molecules can be described at low concentrations by a Lorentzian, whose width depends linearly on the concentration. The analysis of the experimental data showed that the main contribution to the additional inhomogeneous broadening in the investigated systems is not given by the electrostatic and dispersive interactions, but by the fluctuation of the nuclear coordinates of the chromophore. (C) 1998 American Institute of Physics.