Although the simulated and experimental e - (aq) concentrations differ, direct comparison to the experimental spectra can be made by taking the difference between e - (aq) and pure-water's XAS. This is shown in Fig. , with a peak in the theoretical difference spectrum (solid black curve) at 533.1 eV, in excellent agreement with an experimental peak at 533.2 eV extracted from a Lorentzian fit to the data (dashed red curve, HWHM = 0.87 eV). We note that the width of the theoretical spectrum is somewhat underestimated compared to experiment, likely due to increased lifetime broadening of the 533 eV peak compared to the preedge peak (theoretical spectra were convolved with a uniform Lorentzian function of HWHM = 0.2 eV to reproduce the experimental XAS of neat water below 535 eV -see SI for details). The experimental oscillator strength of the 533 eV feature can be extracted by applying the Beer-Lambert law to the integrated fit of the experimental absorbance change of 0.095, using the reported path length of 2.09 µm and water ionization fraction of 0.8-1.7%, yielding oscillator strengths in the range of 0.016 to 0.031. In comparison, the theoretical oscillator strengths for transitions below 533.9 eV sum to 0.019, which is pleasingly within the experimental range.