Reference signal for spectra was taken from an empty subphase (setup scheme in Figure ). This method allowed us to measure amplified monolayer reflectance as described elsewhere, so graphed absorption spectra for convenient understanding were all multiplied by negative unity. Luminescence of a floating layer was measured by placing the reflectometry probe over a water subphase in the same position as for absorbtion, yet deuterium-halogen irradiation was turned off and fluorescence was measured in a diffuse reflectivity mode as excited with collimated beam from monochromatic light source, again referenced to pure water subphase diffuse reflection signal.