title: The soft optic mode in ferroelastic Rb(4)LiH(3)(SO(4))(4).
abstract: Raman scattering measurements were performed on the ferroelastic compound Rb(4)LiH(3)(SO(4))(4) to determine the nature of the structural transition observed at T(c) = 134 K. A double-grating spectrometer was used to obtain the Raman active B modes of Rb(4)LiH(3)(SO(4))(4). Back-scattering measurements, as a function of temperature, reveal that the 31  cm(-1) mode shows softening consistent with that of an order parameter. As a result, our investigation indicates that the structural transition in Rb(4)LiH(3)(SO(4))(4) should be cataloged as a pseudo-proper ferroelastic transition rather than a proper ferroelastic one.
authors.affiliation: Department of Physics and Physical Oceanography, Memorial University, St John's, NF, A1B 3X7, Canada.
authors.forename: O
authors.initials: O
authors.lastname: Aktas
authors.forename: M J
authors.initials: MJ
authors.lastname: Clouter
authors.forename: G
authors.initials: G
authors.lastname: Quirion