Two-photon-induced blue fluorescence from the chlorophyll a dimer in solution☆

Abstract Two-photon-induced blue fluorescence at 460 nm was observed by excitation of the chlorophyll a dimer in solution with laser radiation at 672 nm. This observation of blue emission corresponding to Soret absorption transitions and the recently observed red (Q y band) fluoresence of the chlorophyll a dimer in solution provide further information on the energy levels of this molecule which supports the results of recent resonance Raman studies.