Next, we consider only water molecules in the first solvation shell of the anion. Previous simulations of Raman spectroscopy in halide solutions found that ion specific spectral features could be attributed primarily to these waters closest to the ion. In order to define the first solvation shell, we consider the hydrogen-carbon (HC) radial distribution function, g(r HC ) in Fig. .C. Under all simulation conditions, the g(r HC ) shows a local minimum at 3.5 Å defining the cutoff for first solvation shell Hydrogens. Computing the spectrum of only these waters in Fig. .B, we see a clear spectral peak emerge at 3400 cm -1 . We therefore assign the experimental peak to OH bonds in the first solvation shall of Carbonate. This assignment can be further validated by selecting the OH bonds with a vibration frequency ≤ 3400 cm -1 and computing g(r HC ) for this "High Field" sub-population. In Fig. .C we plot the difference between this sub-population g(r HC ) and that of all Hydrogens for each simulation condition, confirming that the spectral peak can indeed be attributed primarily to the first solvation shell with a small contribution from the second solvation shell. This figure is a statistical assignment of the spectral peak, quantitatively identifying the water subpopulation that is overrepreesented in the spectral region of interest.