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 (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)