OH radical in water studied by Quantum beats on positron annihilation -the effect of water liquid structures-

Abstract

Singlet radical pairs of ortho-positronium and hydroxyl (OH) radical were generated in positron radiolysis in water. Quantum beats on the energy distribution of positron annihilation γ-rays caused by the reaction of electron-spin-correlated pairs of ortho-positronium and OH radical were newly measured at 32°C by using positron annihilation age-momentum correlation (AMOC) measurement. The quantum beats can provide information of hyperfine coupling constants of the OH radical in water liquid structures, and hence can provide the information of change of the water liquid structures. The quantum beats appeared at 32°C could not be explained easily. The reason was continuous and slow change of water liquid structures at 32°C. The water liquid structures probably can be understood by using the positron annihilation quantum beat measurements. © 2010 IOP Publishing Ltd.