Water, Hydrogen Peroxide, and Anions

The relative importance of the processes (84) and (85) in the gas phase has been determined directly using a flash photolysis-resonance fluorescence method.435 It was established that at 105 145 nm, the relative efficiences for reactions (84) and (85) are 0.89 and 0.11, whereas for 145 185 nm reaction (85) is of negligible importance ( 1%). 

In another study it has been shown that 23% of the hydrogen formed on irradiation of water at 147 nm is produced via step (85).43e The new technique of polarized photofluorescence excitation spectroscopy has been applied to the OH radicals produced by reaction (86) on irradiation at 130 nm.437 The 

Iizuka, H. Yamamoto, M. Kotani, and T. Yonetani, Biochim. Biophys. Acta, 1974,351,182. 

Emission (AmaT = 380 nm), assigned to that from the lowest triplet state of water, has been observed following either y-irradiation or mercury sensitization of crystalline H20 or D20.439 For the mercury sensitization a triplet energy-transfer mechanism appears to be operative, while for the y-irradiation the excited state is formed via reaction (88). Photolysis of water adsorbed on various organic materials is observed with short-wavelength u.v. light (A 250 nm).440 

The results of electron impact studies with water are consistent with a vertical excitation energy of 7.4 eV for the ZBX state of water,441 and this has been confirmed by recent calculations on H20.442-445 

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