Rex
V. Gibbons
Geology and Geophysics Branch
NASA - Johnson Space Center
Houston, Texas 77058
Thomas J. Ahrens, George R. Rossman
Division of Geological and Planetary
Sciences
California Institute of Technology
Pasadena, CA 91125
Abstract
The Gaussian resolution procedure of Faye (1975) leading to the
conclusion that the spectral changes in a shock-loaded rhodonite are
the result of a broadening or intensification of the ultraviolet
charge-transfer absorption and that the 540 nm band is present with
comparable intensity in both pre- and post-shock samples is not
physically meaningful because it has ignored the dominant process which
gives rise to the rising baseline "absorption" throughout the
near-infrared and visible spectral regions. That process is
wavelength-dependent scattering.
Optical absorption spectrum of a rhodonite sample 0.31 mm thick recovered from a 496 kbar shock (solid line). The
dotted line is the scattering curve of abraded glass plates which illustrates the wavelength dependence of scattering.
