DOI > 10.5291/ILL-DATA.6-05-993

This proposal is publicly available since 04/15/2023


High-pressure isochronal study on ionic liquid


The objective is to study how the alpha relaxation evolves in an ionic liquid (IL) as a function of T and P, especially along an isochrone (constant relaxation time) found from the fixed window scan technique on IN16B, i.e. on nanosecond time scale, while monitoring the conductivity with dielectric spectrocospy (DS) on slower time scales. As predicted by the isomorph theory, we have shown that both the fast and slow dynamics scale along isochrones in a large part of T,P-phase space in the HP DS-NS cell (LTP-6-7) for a van der Waals liquid. In the proposed IL more than 95% of the total scattering will be incoherent scatt. from the cation. This is of interest since the cations form polar domains on mesoscopic length scales. This experiment will provide information on the dynamics of these heterogeneities as a function of T and P along an isochrone. In addition, the cation has both a methyl group and an alkane side chain, which might give contributions that are different in T,P-dependence. Therefore we do not know whether ILs obey the isomorph theory, which predicts that structural and dynamical properties of ALL time scales should be invariant along the same lines in T,P-phase space.

Experimental Report

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Data Citation

The recommended format for citing this dataset in a research publication is in the following format:

HANSEN Henriette Wase; Karolina Adrjanowicz; Bernhard Frick; LUNDIN Filippa; MATIC Aleksandar and Kristine Niss. (2018). High-pressure isochronal study on ionic liquid. Institut Laue-Langevin (ILL) doi:10.5291/ILL-DATA.6-05-993

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Experiment Parameters

  • Environment temperature

    1.5 - 300 K
  • Experiment energy

    2.08 meV / 6.27
  • Experiment moment

    0.1 - 1.8 -1
  • Experiment res energy

    0.8 eV
  • Experiment res moment

    0.1 -1

Sample Parameters

  • Formula

    • Pyr14-TFSI (1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide)