HR: 14:25h
AN: MR53A-04    [Abstracts]
TI: Synchrotron Infrared Reflectivity of Iron at High Pressure
AU: * Seagle, C T
EM: seagle@uchicago.edu
AF: Dept. of Geophysical Sciences The University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, United States
AU: Heinz, D L
EM: heinz@uchicago.edu
AF: Dept. of Geophysical Sciences The University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, United States
AU: Liu, Z
EM: zxliu@bnl.gov
AF: Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AU: Hemley, R J
EM: r.hemley@gl.ciw.edu
AF: Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, United States
AB: High temperature diamond anvil cell experiments often rely on spectroradiometry for temperature measurement. One of the biggest uncertainties in fitting the emission spectra of the sample is the unknown spectral emissivity of the sample material. We have measured the infrared reflectivity of iron at pressures up to 50 GPa and room temperature at the U2A beamline of the National Synchrotron Light Source using the Fourier Transform Infrared Reflectivity technique in order to evaluate the greybody assumption often applied in spectroradiometry. The emissivity and other optical properties were derived with a Kramers-Kronig analysis. The reflectivity undergoes a discontinuous change in both slope and magnitude at the body centered cubic (bcc) to hexagonal close packed (hcp) phase transition in iron. The data shows that at room temperature, hcp iron is nearly a perfect greybody whereas the emissivity of bcc iron deviates from a greybody.
DE: 3924 High-pressure behavior
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 3947 Surfaces and interfaces
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting