Vivronic spectroscopy of single molecules: Exploring electronic-vibrational frequency correlations within an inhomogeneous distribution

Vibrationally resolved dispersed fluorescence spectra have been obtained from single molecules of terrylene in polyethylene at 1.5 K using excitation wavelengths from 577 to 566 nm, spanning both sides of the inhomogeneously broadened electronic origin. The spectra of different molecules exhibit significantly different frequency and intensity patterns. There is a weak overall correlation between ground state vibrational frequencies and wavelength of the electronic origin, with the redder-absorbing molecules tending to have higher vibrational frequencies. The red-shifted absorbers may reside in smaller cavities in the matrix, thus experiencing both strongerh dispersive interactions and more severe atom-atom repulsions. © 1994.