Effects of temperature on the photo-oxidation quantum yield of aqueous hexacyanoferrate(II) anion

Abstract

The photo-oxidation quantum yield of aqueous hexacyanoferrate(II) anion in the presence of N₂O is found to be moderately dependent on temperature at 253.7 nm, but at 228.8 nm only very slightly dependent, and with a substantially lower quantum yield. In considering models of the photoionization process, it is deduced that, at least at the lower wavelength of irradiation, the charge-transfer metal-to-ligand state produced by light absorption does not quantitatively populate the CTTS state believed to be the intermediate in solvated electron production. At 253.7 nm, where the slope of the plot of In(Φ^–1_e–– 1) against T^–1 is somewhat less than for iodide ion, the involvement of some other fate for the CTML state (but to a much lesser extent than at the higher quantum energy) is a clear possibility.