title: Dynamics of [C3H5N2]6[Bi4Br18] by means of (1)H NMR relaxometry and quadrupole relaxation enhancement.
abstract: (1)H spin-lattice field cycling relaxation dispersion experiments in the intermediate phase II of the solid [C3H5N2]6[Bi4Br18] are presented. Two motional processes have been identified from the (1)H spin-lattice relaxation dispersion profiles and quantitatively described. It has been concluded that these processes are associated with anisotropic reorientations of the imidazolium ring, characterized by correlation times of the order of 10(-8) s-10(-9) s and of about 10(-5) s. Moreover, quadrupole relaxation enhancement (QRE) effects originating from slowly fluctuating (1)H-(14)N dipolar interactions have been observed. From the positions of the relaxation maxima, the quadrupole coupling parameters for the (14)N nuclei in [C3H5N2]6[Bi4Br18] have been determined. The (1)H-(14)N relaxation contribution associated with the slow dynamics has been described in terms of a theory of QRE [Kruk et al., Solid State Nucl. Magn. Reson. 40, 114 (2011)] based on the stochastic Liouville equation. The shape of the QRE maxima (often referred to as "quadrupole peaks") has been consistently reproduced for the correlation time describing the slow dynamics and the determined quadrupole coupling parameters.
authors.affiliation: Department of Physics and Material Research, University of Economy, Garbary 2, 85-229 Bydgoszcz, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Masierak
authors.affiliation: Faculty of Food Sciences, University of Warmia and Mazury in Olsztyn, Oczapowskiego 7, 10719 Olsztyn, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Florek-Wojciechowska
authors.affiliation: Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland.
authors.forename: I
authors.initials: I
authors.lastname: Oglodek
authors.affiliation: Faculty of Chemistry, University of Wroclaw, Joliot Curie 14, 50-383 Wroclaw, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Jakubas
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: A F
authors.initials: AF
authors.lastname: Privalov
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Kresse
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Fujara
authors.affiliation: Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10710 Olsztyn, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Kruk