Hydrated Electron Extinction Coefficient Revisited

Abstract

The extinction coefficient of the hydrated electron (e(-))aq generated by pulse radiolysis is evaluated relative to the methyl viologen radical cation (*)MV(+), whose extinction coefficient at 605 nm has been carefully measured in the past. We find that the room temperature (e(-))aq extinction coefficients reported in the literature are underestimated by 10-20%. We obtain = 22,700 M(-1) cm(-1) for the 20 degrees C hydrated electron at 720 nm, assuming the (*)MV(+) extinction is 13,700 M(-1) cm(-1) at 605 nm. This has implications both for second-order reaction rate measurements of (e(-))aq and for the estimate of its integrated oscillator strength.

Direct observation of the collapse of the delocalized excess electron in water

“…1 shows the THz response of the excess electron in water as a function of the pump-probe delay time t pp , with the THz scanning time t THz kept fixed to the peak of the THz probe field. Pump pulses at 266 nm, 400 nm and 800 nm were used with irradiances of 0.08 TW/cm 2 , 0.3 TW/cm 2 and 1.9 TW/cm 2 , respectively, which resulted in e − aq concentrations of 20 µM, 110 µM and 65 µM, as determined from accompanying experiments using a 800-nm probe pulse (Supplementary Figure 4) [32]. While it is well established that 266 nm and 400 nm pumping generates e − aq by multiphoton processes, photolysis of neat water with 800 nm (1.54 eV) pulses has been explored much less [33,34], because the ionization process is not nearly as well characterized in this case.…”

Nuclear quantum effects in electronically adiabatic quantum time correlation functions: Application to the absorption spectrum of a hydrated electron

“…for the experiment (corresponding to the maximum molar absorption coefficient, 22700 dm 3 mol -1 cm -1 ). 44 The lower panel shows the calculated spectra linearly shifted to align the maximum with the experimental spectrum, 1.72 eV.…”

Purification and Characterization of the [NiFe]-Hydrogenase of Shewanella oneidensis MR-1

“…Following H 2 or N 2 purging, vials were incubated at 30°C for ϳ30 min, at which point the reduction of methyl viologen was evident by a visible blue color in the positive-control vials. The rates for reducing methyl viologen by MR-1 [NiFe]-H 2 ase in both Tris and HEPES buffers were measured by monitoring the changes of reaction solutions at 605 nm (16). Samples were then transferred to a 30°C Forma anaerobic glove box (95% N 2 , 5% H 2 , Ͻ20 ppm O 2 ), where 0.2 ml of H 2 -purged, anoxic 11 mM NH 4 99 TcO 4 in double-distilled H 2 O (ddH 2 O) was added via a 1-ml syringe and a 22-gauge needle.…”