169086
20180913060820.0
A1997WQ14100003
ISI
CONF
Anharmonic properties of Mg2SiO4-forsterite measured from the volume dependence of the Raman spectrum
1997
1997
Conference Papers
The effect of temperature on the Raman spectrum of Mg2SiO4-forsterite is investigated between 100 and 2000 K. The data, combined with those obtained at high pressure, are used to discuss the intrinsic anharmonicity of the Raman-active modes. Anharmonicity of a mode of frequency v(i) is measured through a parameter (a(i)) = (partial derivative ln v(i)/partial derivative T)(v) calculated from the measured temperature and pressure shifts of the vibrational frequency. In forsterite, these parameters are negative, of the order of -10(-5) K-1. Those related to the internal modes of the SiO4 tetrahedra are significantly different (-0.5 10(-5) K-1) from those of the lattice modes (-3 10(-5) K-1). Because of the large temperature range investigated in this study, the temperature and volume dependencies of the a(i) parameters could be estimated for the first time in a mineral, and are shown to be negligible, at least up to 2000 K. The significant non-zero values of the al parameters combined with their small volume dependencies imply that intrinsic anharmonicity in forsterite contributes significantly to entropies and specific heats, even at high pressures, but has negligible effects on thermal pressure and high-temperature equations of state.
forsterite
Raman spectroscopy
high-temperature experiments
equations of state
anharmonicity
High-Pressure
Temperature
Spectroscopy
Forsterite
Minerals
Daniel, I.
Guyot, F.
Gillet, P.
199993
244692
6th International Symposium on Experimental Mineralogy, Petrology and Geochemistry (EMPG-VI)
BAYREUTH, GERMANY
Apr 10-13, 1996
255-262
European Journal Of Mineralogy
9
EPSL
252407
U12330
oai:infoscience.tind.io:169086
SB
conf
EPFL-CONF-169086
OTHER
PUBLISHED
REVIEWED
CONF