TITLE:
Comparison of the Vibrational Spectra of Copper Polysilicate, CuSiO3, with Those of the Prototypic Copper Polygermanate, CuGeO3
AUTHORS:
Marco Meibohm, Hans Hermann Otto
KEYWORDS:
IR/FIR Spectra, Raman Spectra, Factor Group Analysis, Davydov Analysis, Copper Polysilicate, CuSiO3, Copper Polygermanate, CuGeO3, Low-Dimensional Compounds, Spin-Peierls Transition
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.9 No.6,
June
7,
2018
ABSTRACT: Orthorhombic copper polysilicate, CuSiO3, is isotypic to the spin-Peierls compound CuGeO3 and represents a further example of a quasi-one-dimensional spin = 1/2 antiferromagnetic Heisenberg chain system. This is a representation of the first Raman and IR/FIR spectra for CuSiO3, measured at room temperature on polycrystalline samples. A comparison of the optical phonons, predicted by a factor group analysis, with those observed for the CuGeO3 prototype, is presented. A mode assignment for the silicate is given. Surface effects due to a very small crystallite size may cause additional broad bands observed in the Raman spectrum of CuSiO3. From the analysis of the Davydov doublet an intralayer-to-interlayer bond strength of about 40 is derived for the silicate, which is about 20% lower than for the isotypic germanate, allowing for different magnetic responses at low temperature.