Hard mode spectroscopy for the investigation of structural and superconducting phase transitions

Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

“…It is a particularly relevant technique to investigate a variety of phenomena leading to structural heterogeneity, including the incorporation of molecular impurities (Yi et al 2014), exsolution processes (Zhang et al 1996), stacking variations in layered structures , phase transitions (Salje and Yagil 1996) and cationic ordering (Meyer et al 2002).…”

Structural phase transitions in loparite‐(Ce): evidences from Raman light scattering

“…The anomalies in the phonon frequencies can be attributed to two structural phase transitions by using the hard mode spectroscopic approach . Indeed, the phonons with sufficiently high frequencies behave nearly as Einstein oscillators and mainly reflect the properties of a local chemical bonding.…”

High-Temperature Transformations in Calcium Orthovanadate Studied with Raman Scattering

“…The results of this study should be compared with what is known about phase transitions in other compounds with the palmierite-type structure. ,,− Such a comparison should serve as an indirect source of information on the nature and mechanism of the phasetransitions in Ca 3 (VO 4 ) 2 . It is especially important for the case of Raman spectroscopy, which is quite sensitive to probe the transformations of the internal modes of molecular ions but does not provide sufficient information on the lattice oscillations.…”

“…It would be quite interesting to investigate these properties and mechanism of phase transistions in correlation with the chemical substitution at the tetrahedral sites. For example, Pb 3 (PO 4 ) 2 and Pb 3 (P 0.77 As 0.23 O 4 ) 2 undergo a ferroelastic transition between para ( R 3̄ m space group) and ferro ( C 2/ c space group) phases. − This phase change originates from shifts of the Pb (1) atoms from the C 3 axis of the D 3 d site, along three directions of the C 2 axes. It is first order for Pb 3 (PO 4 ) 2 and becomes second order whenever phosphorus is partially substituted by arsenic in the Pb 3 (PO 4 ) 2 −Pb 3 (AsO 4 ) 2 system.…”