The vibrating hydroxide ion in water

► Waters are strongly H-bonded to the ion's O atom, but they are rpelled on the ion's H side. ► The water network keeps the on-top water in place. ► We reproduce both the experimental absolute OH− vibrational frequency and the shift. ► The waters on the ion's O side induce an OH− blueshift. Waters on the H side do too. ► The net effect is a smaller blueshift, due to a frequency vs. field parabola for OH−.