Static and dynamic scavenging of ammoniated electrons by nitromethane

We studied the time-resolved scavenging efficiency of nitromethane for transient electron species in liquid ammonia, at a temperature of 298 K. UV excitation of iodide ions produced fully solvated electrons, as well as transient (I, e − ) and (counterion, e − ) pairs, the overall concentration of wh...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2019, Vol.21 (39), p.21972-21978
Main Authors: Rivas, Nicolás, Sciaini, Germán, Marceca, Ernesto
Format: Article
Language:English
Subjects:
Ammonia
Diffusion rate
Electron distribution
Electrons
Handling equipment
Iodine
Liquid ammonia
Nitromethane
Scavenging
Temporal resolution
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Summary:We studied the time-resolved scavenging efficiency of nitromethane for transient electron species in liquid ammonia, at a temperature of 298 K. UV excitation of iodide ions produced fully solvated electrons, as well as transient (I, e − ) and (counterion, e − ) pairs, the overall concentration of which was monitored by NIR absorption with subpicosecond time resolution. After the UV pulse, the solution absorbance decays almost completely in a few hundreds of picoseconds due to geminate electron-iodine atom recombination and a competitive annihilation channel involving the scavenger. Recombination of transient (I, e − ) pairs follows the well-known kinetic model, while the electron-nitromethane reaction proceeds by two distinct mechanisms: static scavenging (interpreted in terms of the encounter complex model), with a characteristic time shorter than the temporal resolution of the apparatus, or via a diffusion-limited bimolecular reaction, with a rate constant of 1.1 × 10 11 M −1 s −1 . We studied the time-resolved scavenging efficiency of nitromethane for transient electron species in liquid ammonia, at a temperature of 298 K.
ISSN:1463-9076
1463-9084
DOI:10.1039/c9cp03342d