TY  - JOUR
A1  - Abriel, Walter
A1  - Zehnder, Ernst-Jürgen
T1  - Vibronische Kopplung und dynamisch verzerrte Strukturen in Hexahalogenotelluraten(IV): Ergebnisse aus Tieftemperatur-Röntgenbeugungsuntersuchungen (300—160 K) und aus FTIR-spektroskopischen Experimenten (300—5 K) [1]
T1  - Vibronic coupling and dynamically distorted structures in hexahalogenotellurates(IV): low temperatur X-ray diffraction (300—160 K) and FTIR-spectroscopic (300—5 K) results [1]
T2  - Zeitschrift für Naturforschung, B
N2  - From theoretical considerations a dynamically distorted octahedron as a result of vibronic coupling between the ground state and the first excited state should exist for 14 electron AX6E systems like TeX62- . A high symmetry crystal field yielding at least a center of symmetry for the Te position stabilizes this fluctuating structure, otherwise statical distortion will be observed. From X-ray diffraction experiments on antifluorite type compounds A2TeX6 (A = Rb. Cs: X = Cl, Br) the averaged structure (m3̅m symmetry) of the anions was found even at very low temperatures. The thermal parameters are not significantly different from those of similar SnX62 compounds. Distortions therefore are very small and are evident from FTIR spectroscopic meas­urements only. Here very broad T1u-deformation vibration bands are observed down to tempera­tures <10 K without splitting: Astatically distorted species could not be frozen out. In contrast to XeF6 for TeX62- the energy gap between the threefold, fourfold or sixfold minima of the potential surface (according to the symmetry of one component of the T1u-vibration) is very small and shifted to temperatures lower than reached with the devices used for these experiments.
KW  - Lone Pair Electrons
KW  - Vibronic Coupling
KW  - Pseudo Jahn-Teller-Effect
KW  - Tellurates
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/79971
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-799719
SN  - 1865-7117
SN  - 0932-0776
VL  - 42.1987
IS  - 10
SP  - 1273
EP  - 1281
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -