Positron annihilation in the near surface of room temperature ionic liquids

Autor:	Yoshinori Kobayashi, B E O’Rourke, Tetsuya Hirade
Rok vydání:	2017
Předmět:	History Yield (engineering) Annihilation Materials science Electron Computer Science Applications Education Positronium Surface tension chemistry.chemical_compound Positron chemistry Ionic liquid Bound state Atomic physics
Zdroj:	Journal of Physics: Conference Series. 791:012029
ISSN:	1742-6596 1742-6588
DOI:	10.1088/1742-6596/791/1/012029
Popis:	Positronium (Ps; a bound state of an electron and a positron) formation in insulating materials is explained by the spur reaction model. According to the model, electron and/or positron mobility affects the yield of Ps formation. A vertical slow positron beam was used to investigate the surface of a room temperature ionic liquid, N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI). Measurement of positron lifetimes indicated a higher Ps formation probability in near surface of TMPA-TFSI than in the bulk. This result suggests that the electron (and positron) mobility in the near surface may be larger than that in the bulk. Moreover, the longest annihilation lifetime of triplet Ps (ortho-Ps) in the near surface was found to be shorter than that measured in the bulk liquid. Ortho-Ps lifetimes in liquids are well correlated with the surface tension with a shorter lifetime corresponding to higher surface tension. The higher Ps formation yield and the shorter ortho-Ps annihilation lifetime were probably caused by the layered structure in near surface of TMPA-TFSI. A vertical slow positron beam is a strong tool to investigate the surface of room temperature ionic liquids.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::955a1ae2dc9bac62bdd6f64820c7f397 https://doi.org/10.1088/1742-6596/791/1/012029 Zobrazit plný text záznamu