A.I.Kalugin, V.V.Konovalov, N.V.Shokhirev, A.M.Raitsimring.
Photoelectron Injection Into Dilute Electrolyte Solutions.1. Methodology.
Journal of Electroanalytical Chemistry. 359:(1-2) 63-80, 1993.
Abstract:
A general algorithm for the numerical solution that describes the
diffusion and reactions of particles in an arbitrary potential was used
to calculate the photodiffusion currents in dilute electrolyte solutions
in terms of the exact Gouy-Chapman expression for the diffusion potential
f(x). The solution has been obtained for
the simplest case when the product of the capture of solvated electrons,
generated by photoinjection, is a neutral radical. The limited applicability
of the exponential approximation of the phi(x) potential has been demonstrated.
When the electrolyte solution is dilute, the characteristic time of the return
of solvated electrons e(s)(-) to the electrode increases by 3-6 orders of magnitude
within the negative potential range. Thus, when the scavenger concentration is
10-4-10-3 M, it can fully capture es-.
The calculation results have been compared with those of experiments performed in
diluted aqueous solutions of NaF (10-3 - 1 M) at wavelengths of
l = 428-193 nm. The mean distances determined
between es- and the photoelectrode are in fair agreement
with the previous data obtained for concentrated aqueous electrolyte solutions.
We have also found the mean distances, photoinjection threshold and full
photoinjected charge in methanol. The effect of the intensity of light on the value
of photo-induced charge has also been demonstrated.