Joint Raman spectroscopic and quantum chemical analysis of the vibrational features of Cs2RuO4

Abstract

The Raman spectroscopic characterization of the orthorhombic phase of Cs2RuO4 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 Cs2RuO4, Cs2MoO4, and Cs2WO4 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 RuO4 tetrahedra, which lead to a disorder at the RuO4 sites.