Despite strong support for water antibonding orbital occupation by e - (aq) from simulations, direct experimental evidence has been lacking. The strongest evidence comes from Resonance Raman (RR) spectra of e - (aq) , which show a broadening and red shift of water's OH stretch, consistent with the excess electron partially occupying σ * OH orbitals. However, the magnitude of antibonding orbital occupation is not clear from the spectra and furthermore, the interpretation of e - (aq) 's RR is controversial, with an alternate explanation of the OH redshift invoking a strengthening of water-water hydrogen bonds inside the excess electron's charge cloud. 11 Thus, additional spectral probes of σ * OH occupation are highly desired.