Quantum beats on triplet-positronium reactions in water

Hirade, Tetsuya  

Irradiation of water produce some reactive species such as OH radical. OH is formed by the reaction of a water cation and a water molecule just after ionization. On the other hand, a high energy positron injected in water will form cations and excess electrons even at the end part of the track. And hence, some positrons can form Positronium (Ps) with one of the excess electrons. The electrons in OH and Ps used to be in a same orbital in a water molecule before ionization of that water molecule. Therefore they were singlet at the time of the ionization. Every electron have each own hyperfine coupling constant after ionization. In water, reaction between Ps and OH, such as radical reaction or spin conversion, is possible. Therefore, quantum beats on these reaction can occur and the frequency of quantum beats will indicate the hyperfine coupling constant of OH which depends on the structure around OH. Therefore it is becoming possible to discuss the structure of water and reactivity of OH in the structure.