The structure of diaminodurene and the dynamics of the methyl groups

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Sobczyk L, Prager M, Sawka-Dobrowolska W, Bator G, Pawlukojć A, Grech E, van Eijck L, Ivanov A, Rols S, Wuttke J, Unruh T
Zeitschrift: Journal of Chemical Physics
Verlag: AMER INST PHYSICS
Jahr der Veröffentlichung: 2009
Band: 130
Heftnummer: 16
ISSN: 0021-9606
eISSN: 1089-7690


Abstract


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-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

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


Einrichtungen weiterer Autorinnen und Autoren

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


Zitierweisen

APA:
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). https://dx.doi.org/10.1063/1.3125629

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

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