Dear Lubo, Yes, I agree, the original work just means "spread". But the contemporary use implies a more complicated meaning. However, it is not strict, at the level of "feelings", not definitions.
I am putting this query back to the list since it might be interesting to some people. Have a nice weekend! Yaroslav ===8<==============Original message text=============== OK, forget it. The word is taken from Latin (as I wrote before) and has undergone a long way toward its current meaning. If fact, any 'spectrum" (IR, Raman, NMR, etc) or 'diffractogram' are now represented by a spectrum of values, like a diagonalised matrix. Needless to say that in many cases FT is standing between us and the physics and a spectrum we see does not represent (directly!) a picture of the physics behind any more. Lubo On Fri, 12 Feb 2010, Yaroslav Filinchuk, SNBL at ESRF wrote: > Dear Lubo, > > I asked myself the same question about NMR, but decided to keep > this mess of definitions away from people. Indeed, spectrum is > used also to call things not involving energy at all... :) > > Best regards, > Yaroslav > > > > ===8<==============Original message text=============== > Hi Yaroslav, > what about "spectrum of eigenvalues" of a matrix ? Elastic or > inelastic :-) ? > (Sent out-of-group.) > l. > > > 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
