These spectra were acquired as directional hemispheric spectra using the Adams Beckman Dk-2A.
Gaffey M. J, (1976) Spectral Reflectance Characteristics of the Meteorite Classes, J. Geophys. Res., pp. 905-919.
The Original Directional Hemispheric (diffuse) reflectance spectra have no corrections applied to the wavelength values.
The Wavelength Corrected Directional Hemispheric (diffuse) reflectance spectra have wavelength corrections applied based on interlaboratory comparisons for several samples. The function used was an inverse tangent relationship in energy space yielding a correction of between +10-15 nanometers in the .9 to 2.6 micron region. The error in the visible is negligible.