title: Direct Evaluation of the Molar Absorption Coefficient of Hydrated Electron by the Isosbestic Point Method.
abstract: The knowledge of the absorption spectrum of hydrated electron is of importance in numerous pulse radiolysis studies because it is often used for dosimetry or for second-order rate constant determination. We present a direct method for the evaluation of the molar absorption coefficient of the hydrated electron. It is based on the wavelength measurement of isosbestic points during the reaction of e(-)aq with the methylviologen MV(2+) cations which leads to the formation of MV(+•). The molar absorption coefficient of hydrated electron is obtained using the value of the molar absorption coefficient of MV(+•) at the isosbestic point at 600 nm, i.e., ε600nm,(MV(+•)) = 13500 ± 300 L mol(-1) cm(-1). Therefore, at the maximum of the absorption spectrum of e(-)aq at 715 nm, the value is ε715nm,(e(-)aq) = 19700 ± 400 L mol(-1) cm(-1). The absorption spectrum of the hydrated electron has been re-evaluated and completed from 260 to 850 nm.
authors.affiliation: Laboratoire de Chimie-Physique/ELYSE, UMR 8000 CNRS/UPS, Univ. Paris Sud, Université Paris-Saclay , Bât. 349, F-91405 Orsay Cedex, France.
authors.forename: Fayçal
authors.initials: F
authors.lastname: Torche
authors.affiliation: Laboratoire de Chimie-Physique/ELYSE, UMR 8000 CNRS/UPS, Univ. Paris Sud, Université Paris-Saclay , Bât. 349, F-91405 Orsay Cedex, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marignier