摘要The compressional behaviour of natural pyrope garnet is investigated by using angle-dispersive synchrotron radiation x-ray diffraction and Raman spectroscopy in a diamond anvil cell at room temperature. The pressure-induced phase transition does not occur under given pressure. The equation of state of pyrope garnet is determined under pressure up to 25.3GPa. The bulk modulus KT0 is 199GPa, with its first pressure derivative K'T0 fixed to 4. The Raman spectra of pyrope garnet are studied. A new Raman peak nearly at 743cm-1 is observed in a bending vibration of the SiO4 tetrahedra frequency range at pressure of about 28GPa. We suggest that the new Raman peak results from the lattice distortion of the SiO4 tetrahedra. All the Raman frequencies continuously increase with the increasing pressure. The average pressure derivative of the high frequency modes (650--1000cm-1) is larger than that of the low frequency (smaller than 650cm-1). Based on these data, the mode Gruneisen parameters for pyrope are obtained.
Abstract：The compressional behaviour of natural pyrope garnet is investigated by using angle-dispersive synchrotron radiation x-ray diffraction and Raman spectroscopy in a diamond anvil cell at room temperature. The pressure-induced phase transition does not occur under given pressure. The equation of state of pyrope garnet is determined under pressure up to 25.3GPa. The bulk modulus KT0 is 199GPa, with its first pressure derivative K'T0 fixed to 4. The Raman spectra of pyrope garnet are studied. A new Raman peak nearly at 743cm-1 is observed in a bending vibration of the SiO4 tetrahedra frequency range at pressure of about 28GPa. We suggest that the new Raman peak results from the lattice distortion of the SiO4 tetrahedra. All the Raman frequencies continuously increase with the increasing pressure. The average pressure derivative of the high frequency modes (650--1000cm-1) is larger than that of the low frequency (smaller than 650cm-1). Based on these data, the mode Gruneisen parameters for pyrope are obtained.
MA Yan-Mei;CHEN Hai-Yong;LI Xue-Fei;GAO Ling-Ling;CUI Qi-Liang;ZOUGuang-Tian. Raman and X-Ray Investigation of Pyrope Garnet (Mg 0.76 Fe 0.14 Ca 0.10)3Al2Si3O12 under High Pressure[J]. 中国物理快报, 2007, 24(5): 1180-1182.
MA Yan-Mei, CHEN Hai-Yong, LI Xue-Fei, GAO Ling-Ling, CUI Qi-Liang, ZOUGuang-Tian. Raman and X-Ray Investigation of Pyrope Garnet (Mg 0.76 Fe 0.14 Ca 0.10)3Al2Si3O12 under High Pressure. Chin. Phys. Lett., 2007, 24(5): 1180-1182.
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