Fluorescence spectra of all-trans-1,6-dipheny1-1,3,5-hexatriene were measured in n-hexadecane at 99 degrees C by varying lambda(exc) in the 294-404 nm range. Resolution of this spectral matrix into s-trans,s-trans and s-cis,s-trans conformer fluorescence spectra yields the lambda(exc) dependence of fractional contributions which are converted to conformer specific fluorescence excitation spectra. Conformer absorption spectra obtained from the fluorescence excitation spectra are remarkably similar, but differ significantly from absorption spectra derived from a spectrothermal absorption spectral matrix measured in n-alkanes under isopolarizability conditions. The results reveal substantial conformer equilibration in the excited state. Theory is consistent with adiabatic conformer equilibration in the 2(1)Ag state. (C) 2016 Elsevier B.V. All rights reserved.