Temperature dependence of ortho-positronium lifetime in a room temperature ionic liquid

Hirade, Tetsuya  ; Michishio, Koji*; Kobayashi, Yoshinori*; Oshima, Nagayasu*

Positronium (Ps) forms bubbles in liquids, and the bubbles become larger due to the lower surface tension at higher temperatures, resulting in longer o-Ps lifetimes. In room-temperature ionic liquids, it has been shown that the structure of Ps bubble is different and depends on the structure formed by the Coulomb force of the ions. We successfully obtained that the o-Ps lifetime did not increase at high temperatures. The existence of new state of Ps bubble was further clarified.