Transition-moment directions of selected carbocyanines from emission anisotropy and linear dichroism measurements in uniaxially stretched polymer films

Based on the Kawski–Gryczyński method the values of angle between absorption and fluorescence transition moments of carbocyanines are given. This method is applied to the linear molecules: 3,3′-diethylthiacyanine iodide (DTTHCI), diethyloxacarbocyanine iodide (DOCI), 3,3′-diethyl-9-methylthiacarbocyanine iodide (MDTCI), diethylthiacarbocyanine iodide (DTCI) and 3,3′-diethyloxadicarbocyanine iodide (DODCI). rly located transition moments polarized approximately along the long axis of DTTHCI, DOCI, MDTCI, DTCI and DODCI are responsible for absorption and fluorescence (β ⩽ 10°), when exciting in the long wavelength absorption band. The results are compared with relevant data obtained from linear dichroism measurements, energy migration data in partly ordered films and general Perrin formula.