A nuclear magnetic resonance study of tetramethylammonium cadmium chloride (TMCC)
Autor: | Zbigniew Czapla, Dieter Michel, S. Mulla-Osman, W.-D. Hoffmann |
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Rok vydání: | 1998 |
Předmět: | |
Zdroj: | Journal of Physics: Condensed Matter. 10:2465-2476 |
ISSN: | 1361-648X 0953-8984 |
DOI: | 10.1088/0953-8984/10/11/010 |
Popis: | The structural phase transition at 118 K was investigated in (TMCC) crystals by means of NMR spectroscopy. For a rotation around different crystallographic axes the angular dependencies of NMR spectra are given. The three observed lines and their angular variation show the hexagonal symmetry of the crystal in the room-temperature phase. The principal axes and principal values of the electric field gradient (EFG) tensors have been evaluated for this phase applying the Volkoff formalism. The direction of the largest principal value coincides with the projection of the Cd-Cl bond direction into the (001) plane. Below the phase transition temperature in the ferroelastic phase a splitting of each NMR line into three pairs was observed. The line splitting into three pairs is explained by the loss of the hexagonal symmetry and by the coexistence of three different domains. The three different tensors of the EFG were calculated for the inequivalent chlorine atom positions. |
Databáze: | OpenAIRE |
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