Hello Herman!

04 May 05 19:55, Herman Trivilino wrote to Gerrit Kuehn:

 GK>> Not neccessarily sloppy. As I said above: Photons having an
 GK>> energy of 10000 cm^-1 are correct and understandable in a
 GK>> spectroscopic context.

 HT> The inverse centimeter is NOT a unit of energy.  It's a unit of 

Of course it is. This unit is also known as "Kayser".

 HT> something known as the wave number.  For example, 10 000 cm^-1 means 
 HT> that there are 10 000 waves in a centimeter.  While this number 
 HT> certainly is proportional to the energy for two waves with the same 
 HT> wave speed, it is not a measure of the energy.

It's as well a measure of energy as eV or Hz are. They're all called
"energy equivalents" and are valid in their context. Have a look
at http://physics.nist.gov/cuu/Constants/factors.html

 HT> I know for a fact that researchers who routinely work in units of 
 HT> wavenumbers THINK of the wavenumber as an indicator of the amount of 
 HT> energy.  They can get away with that because it works for them in 
 HT> that one specialized area.  When these researchers publish their 
 HT> work, they do not use the wavenumber as a measure of energy.

Well, I don't know from where you get your facts. The papers and books I
read use cm^-1 for measuring energies quite frequently, e.g. to denote the
energies of atomic levels. As I said before that's a wide-spread habit
among people dealing with atomic physics and spectroscopy, even in
publications. Even papers published by NIST do so, I can see nothing wrong
with that.


Regards,
Gerrit

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