Energy partitioning in the reaction O(1D) + H2O → OH + OH

The rotation-vibration population distribution of nascent OH formed by the exothermic reaction 0(1D) + H2O → OH + OH has been observed by means of time-resolved resonance absorption using a pulsed laser with sub-Doppler linewidth. The translational energy of most of the product molecules is distributed according to a temperature of about 4800 K. One half of the OH is found in a rotational distribution described by T approx. 400 K, whereas the other half is rotationally hot (1900 K). The vibrational distribution is extremely non-thermal. The populations in the two different spin states 2PI3sub(/)2 and 2PI1sub(/)2 are statistical, but nonstatistical in the corresponding Λ components. (orig.)