Re: diffraction patterns or spectra

[Yaroslav Filinchuk, SNBL at ESRF]

Title: Re: diffraction patterns or spectra

Dear Brian,

to me spectroscopy sounds as a technique were an energy spectrum is used, 
i.e. the light of different energies  has a different absorption coefficient (IR),
or there is a different energy transfer for a fixed wavelength (Raman, INS, IXS).
X-ray diffraction, even the wavelength-dispersive, is elastic and neither uses
different absorption properties at different wavelength. So, it does not reflect
"nature" of spectroscopy. Therefore we should avoid using the word "spectrum" for
a diffraction pattern of any type. This is my view, with no references to books or 
Wikipedia, and I wonder if many of you share it...

Best regards,
 Yaroslav


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diffraction patterns are often referred to as diffraction
spectra. But we all know that diffraction is not a spectroscopic technique.

A spectrum refers to a wavelength-dispersive measurement, while CW diffraction
is spatially resolved. Either diffraction pattern or diffractogram is the choice 
of the cognoscenti IMHO, except perhaps in the case of TOF and energy-dispersive x-ray. 

Brian


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