Semiclassical description of Intermolecular Coulombic Electron Capture in solutions

Abstract

In this work, we present a semiclassical approach to model Intermolecular Coulombic Electron Capture (ICEC) in aqueous solutions using molecular dynamics simulations with OpenMM. We investigate the behavior of an excess electron in the presence of cations (Fe$^{3+}$) in water, focusing on the influence of electron energy and cation concentration on the ICEC quantum yield. Our simulations reveal that the ICEC quantum yield approaches unity at higher concentrations and initial electron energies, while it decreases at lower concentrations due to electron energy loss before reaching the cation.

Figures (5)

• Figure 1: Snapshot of the simulation box: O are in red, H in white, Fe in pink and e in blue.
• Figure 2: Distance (in nm) between the electron and the cation (in black) and electron kinetic energy (in red) as function of time for a typical trajectory at C=0.2mol/L. The dashed line indicates the ICEC threshold (i.e. below this line ICEC is not energetically possible).
• Figure 3: ICEC quantum yield as function of the cation concentration. The results from the simulations (dots) were fitted with a quadratic function (lines); see text.
• Figure 4: ICEC electron energy distribution for different times for C=0.2mol/L and the initial electron energy of 50 eV.
• Figure 5: Total ICEC electron energy distribution for different concentrations. From top to bottom: initial electron energy = 10, 50 and 100 eV.