Direct Evidence for Transient Pair Formation between a Solvated Electron and H3O(+) Observed by Picosecond Pulse Radiolysis.
The reaction between the solvated electron and hydronium cation H3O(+) in water constitutes a fundamental reaction in chemistry. Due to significant rearrangement of solvent molecules around both the electron and H3O(+), the reaction rate of this process is not controlled by diffusion. The presence of a reaction barrier suggests the formation of an intermediate that has so far not been observed. Here, the time-resolved visible absorption spectra in three concentrated acid solutions, perchloric, sulfuric, and phosphoric, at various concentrations are recorded by the picosecond pulse radiolysis method. In contrast to previous reports, a strong blue shift of the absorption band of the solvated electron in acidic solutions compared to neat water is clearly observed, consistent with formation of a pair between the solvated electron and hydronium cation.
Laboratoire de Chimie Physique, UMR 8000 CNRS-Université Paris-Sud, ELYSE, Bât. 349, 91405 Orsay, France.
Jun
J
Ma
Laboratoire de Chimie Physique, UMR 8000 CNRS-Université Paris-Sud, ELYSE, Bât. 349, 91405 Orsay, France.
Uli
U
Schmidhammer
Laboratoire de Chimie Physique, UMR 8000 CNRS-Université Paris-Sud, ELYSE, Bât. 349, 91405 Orsay, France.
Mehran
M
Mostafavi
highly concentrated acidic solution; picosecond pulse radiolysis; solvated electron; transient pair