J. Phys. II France
Volume 3, Numéro 2, February 1993
Page(s) 217 - 225
DOI: 10.1051/jp2:1993124
J. Phys. II France 3 (1993) 217-225

Inelastic neutron scattering study of proton dynamics in Cs 3H(SeO 4) 2 and Rb 3H(SeO 4) 2

A.V. Belushkin1, J. Tomkinson1 and L.A. Shuvalov2

1  Rutherford Appleton Laboratory, Chilton, Great-Britain
2  Institute of Crystallography, Moscow, Russia.

(Received 18 August 1992, revised 19 October 1992, acceptec 10 November 1992)

The proton dynamics of the Cs 3H(SeO 4) 2 and Rb 3H(SeO 4) 2 have been studied by inelastic neutron scattering in a temperature range from 5 K to 60 K. The results are discussed in comparison with the isostructural acid sulphates, however the dynamics of the selenates is quite different. The splitting of selenate bands at low temperatures for both Cs and Rb salts indicate a phase transition to low symmetry. The anomalous temperature dependence of hydrogen bond bending modes in the Cs salt is discussed in the framework of interactions between strongly anharmonic stretching modes and bending vibrations.

63.20 - 64.70K

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