Picosecond study of the temperature dependence of electron transfer in the excited singlet state of a polymethine dye

Abstract

The temperature dependence of the photoinduced electron transfer from the polymethine dye 1,1′-dimethyl-3,3′-di- p—N-phenylacetanilino-6,6′-di-cyanoimidacarbocyanine iodide to methylviologen has been investigated in methanolic solution by means of picosecond fluorescence spectroscopy in the temperature range 278–328 K. At an acceptor concentration of 0.5 mol/ℓ an activation energy Δ G* = (24.1 ± 3.5) kJ/mol, and a value of the frequency factor A=4.7 × 10 14 ℓ mol −1 s −1 have been evaluated from the experimental data.