Joint Raman spectroscopic and quantum chemical analysis of the vibrational features of Cs 2 RuO 4

The Raman spectroscopic characterization of the orthorhombic phase of Cs RuO was carried out by means of group theory and quantum chemical analysis. Multiple models based on ruthenate (VI+) tetrahedra were tested, and characterization of all the active Raman modes was achieved. A comparison of Raman spectra of Cs RuO , Cs MoO , and Cs WO was also performed. Raman laser heating induced a phase transition from an ordered to a disordered structure. The temperature-phase transition was calculated from the anti-Stokes/Stokes ratio and compared with the ones measured at macroscopic scale. The phase transition is connected with tilting and/or rotations of RuO tetrahedra, which lead to a disorder at the RuO sites. © 2015 The Authors. published by John Wiley & Sons Ltd.