A single-molecule study of the relation between the resonance frequency and the orientation of a guest molecule in a Shpol'skii system

Abstract An optical single-molecule study is reported of a quickly frozen solution of 2.3,8.9-dibenzanthanthrene (DBATT) in n -tetradecane at 1.4 K. The orientation has been measured of several hundreds of DBATT molecules within a confocal detection volume of ∼ 10 μm 3 as a function of their resonance frequency in the range of the two 0–0 bands in the fluorescence-excitation spectrum. Each band is found to correspond to a distinct distribution of orientations of DBATT molecules. A particular resonance frequency within a band is not correlated with a specific molecular orientation.