singlet-singlet absorption

Absorption which results in the transition from the singlet ground state of the molecule into singlet excited states ( $S 0$ → $S n$ ) and leads to the UV/visible absorption spectrum.

Source:

PAC, 1984, 56, 231 (Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy) on page 234