Eur. Phys. J. Special Topics 189, 263-271 (2010)
https://doi.org/10.1140/epjst/e2010-01331-y

Regular Article

Comparison of the dynamics of MIL-53(Cr) and MIL-47(V) frameworks using neutron scattering and DFT methods

¹ Institut de Recherches sur la Catalyse et l’Environnement de Lyon, CNRS, UMR 5256, Université Lyon 1, 2 avenue Albert Einstein, 69626 Villeurbanne, France
² Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Science, Prospekt Akademika, Lavrentieva 5, Novosibirsk 630090, Russia
³ Laboratoire de Spectrométrie Physique, CNRS, Université Joseph Fourier, BP. 87, 38402 Saint-Martin-d’Hères, France
⁴ Institut Laue-Langevin, BP. 156, 38042 Grenoble, France
⁵ Institut Lavoisier, UMR CNRS 8180, Université de Versailles Saint-Quentin-en-Yvelines, 78035 Versailles Cedex, France

^a e-mail: herve.jobic@ircelyon.univ-lyon1.fr

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

Abstract

The low-frequency modes of MIL-47(V) and MIL-53(Cr) frameworks have been measured by inelastic neutron scattering. The librational modes of benzene are very close in frequency in the two structures. First-principles calculations have been performed to assign the measured spectra. The calculated values of the rotational barriers of the benzene rings are in reasonable agreement with experimental data. The relatively large barriers (413–588 meV) explain the absence of quasi-elastic broadening on the neutron time scale.