Science, 288, pp. 1626-1629, (2000) [doi: 10.1126/science.288.5471.1626]
Raman spectroscopy of Iron to 152 Gigapascals: Implications for Earth's Inner Core
S. Merkel, A.F. Goncharov, H.K. Mao, P. Gillet and R.J. Hemley
Raman spectra of hexagonally closed packed iron (e-Fe) have been measured from 15 to 152 gigapascals using diamond-anvil cells with ultrapure synthetic diamond anvils. The results give a Grneisen parameter g0 = 1.68 (+/-0.20) and q = 0.7 (+/-0.5). Phenomenological modeling shows that the Raman-active mode can be approximately correlated with an acoustic phonon and thus provides direct information on the high pressure elastic properties of iron, which have been controversial. In particular, the C44 elastic modulus is found lower than previous determinations. This leads to changes of about 35% at core pressures for shear wave anisotropies.
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