The photoluminescence (PL) spectra of dilute solution and single crystals of distyrylbenzene show unique temperature dependent vibronic structures. The characteristic single frequency progression at high temperatures is modulated by a low frequency progression series at low temperatures. None of the series side band modes corresponds to any of the distyrylbenzene Raman frequencies. We explain these PL properties using a time dependent model with temperature dependent damping, in which the many-mode system is effectively transformed to two- and then to a single "apparent" mode as damping increases.
Categories: cond-mat.other