Anion-to-water CT stands out as the only energy component whose magnitude is larger at the air/water interface for some of the ions. In fact, it is larger specifically for the traditional surface-active anions: Br -, I -, ClO - 4 , and SCN -. However, NO - 3 can also be detected in surface-sensitive vibrational spectroscopy , yet for that species E CT is essentially the same at the interface as it is in bulk water. The Cl -ion is a borderline case whose average CT energy is slightly more stabilizing at the interface, albeit by less than one standard deviation in the fluctuations. In all cases, the CT energy constitutes less than 20% of the total induction energy, meaning that it is at least 5× smaller than the CT-free polarization energy, the latter of which does not exhibit a surface preference and is in fact larger in bulk water. Nevertheless, the consequences of this "excess" CT for soft anions at the air/water interface interface seems worth pursuing in future work, especially in the context of VSFG experiments. Intermolecular CT mechanisms have been invoked in the past to explain the surface charge of liquid water that is inferred from electrophoretic measurements .