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
--
Radovan Cerny
Laboratoire de Cristallographie
24, quai Ernest-Ansermet
CH-1211 Geneva 4, Switzerland
Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08
mailto : radovan.ce...@unige.ch
URL : http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
