Fluorescence emission of excited hydrogen atoms after core excitation of water vapor

The Balmer emission from atomic hydrogen has been recorded across the resonances at the oxygen K edge of the water molecule using synchrotron radiation excitation. The emission is observed to be strongest at excitations to Rydberg resonances. The observations are interpreted using a qualitative model for the dynamics of the core-to-Rydberg excited molecule. The model links the quantum state of the core-excited water molecule via resonant Auger decay and subsequent dissociation to the state of the fluorescing hydrogen atom.