Eur. Phys. J. Special Topics 189, 279-284 (2010)
https://doi.org/10.1140/epjst/e2010-01333-9

Regular Article

Dynamic study of N’N-dimethylparanitroaniline encapsulated in silicalite-1 matrix using neutron spin-echo spectroscopy

¹ Institut Néel, UPR 2940, CNRS/UJF, 25 avenue des Martyrs, BP. 166, 38042 Grenoble Cedex 09, France
² Catalysis Division, National Chemical Laboratory, Pune 411008, India
³ Laboratoire Léon Brillouin (CEA-CNRS), 91191 Gif-sur-Yvette Cedex, France
⁴ Cristallographie, Résonance Magnétique et Modélisation, UMR 7036 CNRS-Université de Nancy, 54506 Vandoeuvre-lès-Nancy, France
⁵ National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA

^a e-mail: michel.anne@grenoble.cnrs.fr

Received: 1 September 2010
Revised: 14 September 2010
Published online: 12 November 2010

Abstract

The present work focuses on the dynamic studies of N’N-dimethyl-paranitroaniline (dmpNA) encapsulated in silicalite zeolite. Quasielastic neutron scattering (QENS) experiments are carried out using neutron spin-echo technique. Polarisation of the scattered neutron beam is measured at carefully chosen values of Q = 0.35, 0.9, 1.1 and 1.45  Å⁻¹ at fixed T = 298  K and at fixed Q = 0.9  Å⁻¹ at 150, 200, 250 and 298 K. This gives insight into the motion and the related activation energy of the guest dmpNA molecule. The quasielastic signal observed in the present system within the time range considered is due to fast local rotational motions of protons of the end methyl groups. The results are in good agreement with the dynamics of methyl group rotations reported in the literature by back-scattering QENS technique.