State distribution of the OH product following H₂O photodissociation at two photon wavelengths. (a) At λ = 166 nm, H₂O dissociating via its first excited à electronic state and producing OH in rotationally cold but vibrationally hot states. (b) At λ = 121.6 nm, H₂O dissociating via its second excited electronic state and producing OH in rotationally hot but vibrationally cold states. Vibrational quantum numbers are color coded as indicated in the top panel. The distributions within OH(X²Π, v) and OH(A²Σ⁺, v) are plotted in solid and dashed lines, respectively, as a function of the rotational quantum number N. Only vibrational levels that contribute at least 1.5% to the population of nascent OH are shown.