Quantum beats measured by positron annihilation methods, 1; A New method for radicals

Hirade, Tetsuya  ; Lee, J.

Positronium (Ps) formed in water and OH radical are a geminate radical pair. The geminate radical pair is in a singlet state initially. Both of the spins are in different conditions and then the spin state changes between singlet and triplet. The rotational frequency of Ps is much faster than that of OH radical and a half has the same direction of the rotation and the other half have the opposite direction. The measured phenomenon is the mixture of the both cases and then there will be swells on the probability of the singlet state. The radical reaction of Ps and OH radical is affected by the spin state and then the swells of the spin state can be detected by the positron annihilation experiment as quantum beats. The quantum beats in water were successfully observed.