H2O quenching of the transitions H(n=3→n=2) and O(3p 3P→3s 3S) in pulse radiolytically excited water vapor

Time resolved spectral and kinetic studies at the nanosecond level were carried out on water vapor excited by a 0.53 MeV pulsed electron beam. Three electronically excited species: H(n=3), O(3p 3P), and O(3p 5P), were identified in the 600–900 nm emission region investigated. The rate constants for the very fast quenching by H2O at 294 K of H(n=3) and O(3p 3P) were determined to be (9.1±1.6) ×10−9 cm3 molecule−1 s−1 and (9.4±1.5) ×10−10 cm3 molecule−1 s−1, respectively. The rate constant for O(3p 3P) has not been determined previously.