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Hirade, Tetsuya
Acta Physica Polonica A, 132(5), p.1470 - 1472, 2017/11
Times Cited Count：3 Percentile：28.88(Physics, Multidisciplinary)The positron annihilation lifetime measurements in RTILs showed very strange results. Finally, positron annihilation age-momentum correlation (AMOC) measurements indicated that it was caused by slow bubble formation in RTILs. Then I discovered the oscillation of o-Ps annihilation rates in room temperature ionic liquids (RTILs) which indicated, probably, the oscillation of the Ps bubble. Stepanov et al. calculated change of the bubble size in many liquids and the oscillation of the bubble was not expected except for a liquid He. It means that the structure of RTILs in nanometer scale is very different from usual liquids. Moreover, o-Ps pick-off annihilation rates seems to be too small for the macroscopic surface tension of RTILs. I am going to discuss what you can study by the positron annihilation methods for the structure of RTILs in nanometer scale.
Ito, Yasuo*; F.M.H.Mohamed*; Seguchi, Tadao; *
Radiation Physics and Chemistry, 48(6), p.775 - 779, 1996/00
Times Cited Count：19 Percentile：81.64(Chemistry, Physical)no abstracts in English
Hirade, Tetsuya
no journal, ,
Positronium (Ps) creates a bubble in liquids because of a negative work function and the ortho-Ps annihilation probability depends on the size of the bubble. The oscillation of the ortho-Ps annihilation probability at very young positron ages, i.e. before 1ns, was successfully observed in room temperature ionic liquids (RTILs). The frequency of the oscillation deceased just above the melting point. Moreover, the stable annihilation rates at older positron ages in RTILs are much smaller than the annihilation rates of other liquids having similar surface tensions, and the rates do not become smaller at higher temperatures. These phenomena are probably caused by the complicated RTIL structure.
