Doppler-Broadening (Db) Measurement Of Ionic Liquids Using A Monoenergetic Positron Beam

A positron beam is applied to investigate 1-Butyl-3-methyl-imidazolium-hexafluorphosphat (BMIm-PF6) by Doppler broadening (DB) measurements. A liquid is principally free of lateral inhomogeneities while its depth dependent structure is influenced by the surface. This structure is studied in-situ and non-destructively by the use of a monoenergetic positron beam.In a second measurement, the ionic liquid performs different phase changes during heating and cooling. Temperature dependent DB measurements of the 511 keV photopeak show very clear influence of phase transitions (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim