In this study, we report the results of an in situ X-ray absorption spectroscopy investigation of the La2O3-B 2O3-GeO2 (LBG) glass compressed in a diamond anvil cell until 17 GPa at ambient temperature. A pressure-induced coordination change of germanium from fourfold to sixfold is shown here. The analysis of Ge K-edge X-ray absorption near-edge structure spectra supports a model of mixing of fourfold and sixfold coordinated Ge sites during the compression/ decompression cycle. This transformation proves to be irreversible: about 25% of sixfold coordinated Ge still exists at ambient pressure. This phenomenon underlines a polymorphism property of the LBG glass, whose origin lies in the complexity of composition.
Permanent Ge coordination change induced by pressure in La 2O3-B2O3-GeO2 glass
Trapananti A.;
2010-01-01
Abstract
In this study, we report the results of an in situ X-ray absorption spectroscopy investigation of the La2O3-B 2O3-GeO2 (LBG) glass compressed in a diamond anvil cell until 17 GPa at ambient temperature. A pressure-induced coordination change of germanium from fourfold to sixfold is shown here. The analysis of Ge K-edge X-ray absorption near-edge structure spectra supports a model of mixing of fourfold and sixfold coordinated Ge sites during the compression/ decompression cycle. This transformation proves to be irreversible: about 25% of sixfold coordinated Ge still exists at ambient pressure. This phenomenon underlines a polymorphism property of the LBG glass, whose origin lies in the complexity of composition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
