Matteo,

On Fri, Apr 1, 2016 at 8:35 AM, Matteo Busi <basebush@gmail.com> wrote:

Hi Bruce,
Now this is clear.
In my case the correction I have to perform requires these measured/evaluated parameters: chi, mu (not sure if it's better to work with normmu here) and the background function.
Is it physically meaningless to have the mu(k) and bkg(k) data? If that is not the case I would like to have these two columns exported in the ascii chi(k) file.
So then I can perform the correction and re-import the new corrected chi(k) and make comparison with the uncorrected.

Kind regards,
Matteo

It would certainly help (and by that I mean "help you get the answers you're looking for") if you gave us more details about what you're trying to do rather than ask for how to what you think you want to do.

Just to be clear: Converting from E to k does not involve a Fourier transform, just
k = sqrt((2m*e/hbar**2)*(E-E0))

for k in Ang^-1 and E in eV, that's k ~= sqrt(0.262468*(E-E0))

I'm not sure what you're trying, but I would image you want to use normalized mu(E) or at least pre-edge subtracted mu(E). That is, what we call mu(E) is typically really -ln(I/I0)

where I and I0 are not the actual intensities before and after the sample, but counts or counts per time in some detector that samples the flux. These values include more or less arbitrary scale factors (amplifier gains, etc) included. That means that (unless you very careful) mu(E) does not have meaningful units, certainly not cm^-1 or cm^2/gram.

Normalized mu(E) doesn't have such units either, but it's an easier place to start.

--Matt