The structure of diaminodurene and the dynamics of the methyl groups

Journal article

Publication Details

Author(s): Sobczyk L, Prager M, Sawka-Dobrowolska W, Bator G, Pawlukojć A, Grech E, van Eijck L, Ivanov A, Rols S, Wuttke J, Unruh T
Journal: Journal of Chemical Physics
Publication year: 2009
Volume: 130
Journal issue: 16
ISSN: 0021-9606
eISSN: 1089-7690


Diaminodurene crystallizes in the orthorhombic space group Pbca, with eight molecules in the unit cell. Four inequivalent methyl groups with different environments exist in a molecule. The amino groups are also different, which is well reflected in infrared spectra. Two tunneling modes are resolved at 23.7 and 7.0 mu eV at 4.5 K. Their intensities are consistent with the presence of two further unresolved tunneling modes. Quasielastic spectra are composed of three Lorentzians of equal intensities. The two low activation energies and tunnel modes are modeled into consistent rotational potentials. The third activation energy and a librational band are used to guess the strength of the two stronger rotational potentials. The internal modes related to the torsional/librational vibrations mix with ring torsions in the range of 70-220 cm(-1). This way the tunnel modes couple to ring torsions whose energy determines the broadening of both tunnel bands. The calculations for free molecules yield mode frequencies a little bit lower than the experimental inelastic neutron scattering (INS) values. Application of theoretical methods elaborated for the crystalline state leads to a satisfactory consistency. It is also valid for bending modes of NH(2) groups, which in the solid state show much higher frequencies than in the gas phase, as expected. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3125629]

FAU Authors / FAU Editors

Unruh, Tobias Prof. Dr.
Professur für Nanomaterialcharakterisierung (Streumethoden)

External institutions with authors

Forschungszentrum Jülich GmbH (FZJ)
Institute Laue-Langevin (ILL)
University of Wroclaw
West Pomeranian University of Technology Szczecin / Zachodniopomorski Uniwersytet Technologiczny w Szczecinie (ZUT)

How to cite

Sobczyk, L., Prager, M., Sawka-Dobrowolska, W., Bator, G., Pawlukojć, A., Grech, E.,... Unruh, T. (2009). The structure of diaminodurene and the dynamics of the methyl groups. Journal of Chemical Physics, 130(16).

Sobczyk, Lucjan, et al. "The structure of diaminodurene and the dynamics of the methyl groups." Journal of Chemical Physics 130.16 (2009).


Last updated on 2019-02-08 at 09:02