High-Pressure Raman Spectra Of Sr-Substituted Gamma-Ca3-Xsrx(Po4)(2)

By using diamond anvil cell (DAC), high-pressure Raman spectroscopic studies of Sr-substituted gamma-Ca3-xSrx(PO4)(2) (x = 0.5, 1, 2) were carried out up to 30.7, 32.4 and 31.4 GPa, respectively. No pressure-induced phase transformation was observed in the present studies. The behaviors of the phosphate modes in gamma-Ca3-xSrx(PO4)(2) (x = 0.5, 1, 2) below 14.4 GPa were quantitatively analyzed since a methanol:ethanol:water (16:3:1) mixture was used as the pressure medium in DAC. The Raman wavenumbers of all PO4 vibrations increased linearly and continuously with pressure for gamma-Ca3-xSrx(PO4)(2) (x = 0.5, 1, 2). With the increasing content of Sr, the corresponding pressure coefficients alpha changed, and the nu(i0) shifts to higher wavenumbers except that for nu(2) bending vibration.