Fig. 1

Optical density spectra of a solid film (solid line, thickness d = 74 nm) compared with spectra measured in dilute (10− 5 M) solvents (toluene - dashed line, DMF - dotted line, ACN - dash-dot line). Wavenumbers are given in kilokayser units (1kK = 1000 cm− 1). The inset shows the semi-structural formula of the DMAC-DPS molecule.