Reaction between ortho-Ps and radical formed in room temperature ionic liquids

Hirade, Tetsuya  

It has been clarified that the annihilation lifetime of triplet positronium in room temperature ionic liquid is shortened at high temperature. This is a phenomenon that has been observed only in water, and is caused by the reaction of triplet positronium and radicals formed at the end part of the incident positron track. Then it is considered that the reaction of triplet positronium also occurs in the room temperature ionic liquid, and the reaction of the spin correlated pair of the triplet positronium and the radical will give the quantum beats as observed in water. Therefore, we performed positron age-momentum correlation (AMOC) measurements on bis(trifluoro-methanesulfonyl)imide (TMPA-TFSI) and successfully observed quantum beats as the energy distribution change of annihilation gamma rays. As a result, it was clarified that radicals formed in room temperature ionic liquids can be detected by positron annihilation method.