Radovan Cerny
Fri, 12 Feb 2010 09:17:15 -0800
Hello Yaro,I think that your view is correct, but if want to play with details, the energy dispersive diffraction like ToF can be called spectroscopy.
From Wikipedia (it's sometimes useful):"Spectroscopy was originally the study of the interaction between radiation and matter as a function of wavelength (λ)."
There is no word whether "function of wavelength" is in the incident radiation or in the radiation emitted, diffracted, transmitted ... by the matter.
So, I would say that the final data is always the diffraction pattern, i.e. how the crystal looks in the reciprocal space. However, the technique to obtain the diffraction pattern, can be called a spectroscopy (like ToF). And the raw data from this technique is a spectrum ...
Have a nice weekend Radovan
On Fri, 12 Feb 2010, Yaroslav Filinchuk, SNBL at ESRF wrote: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 ===8<==============Original message text=============== 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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