good afternooon,
My name is Marcos Eleotério, i am undergraduate in physics and i have a
scholarship at Brazilian Synchroton Light Laboratory, nearly one month ago i
start using the software Athena and Artemis, to analyse some X-ray absorption
data that i have, to make my problem more easy to you understand i list
below the steps that i use in those programs:
1) After a normalization of the data, i put the data in "Athena" turn on
the options: "pre-edge line", "post-edge line" and then "normalized" (in fact
i usually turn the option "flatten" on, in dispite of the fact that i don´t
know what that means, what that means?), i save using the option "Save
chi(k)" in "file".
2)Then i open the program "Artemis" and insert the data saved in the
step "1)" in the column of the middle i click with the right button of the
mouse and select the option "theory", "atoms" and insert the spatial group,
unit cell parameter, and atomic location (here its important to say that the
compound that i'm studying is LaCaMnRuO6 the measure of x-ray absorption was
performed in the K-edge of the Mn, we are interested in
Mn-O ligands so in "Artemis" i only put the data of the Mn and O, right?)
3)I click in the option "run atoms" for each atoms that i inserted the
information, choosing 10 paths in each step, i click the in the option
"run feff" for each atom that i inserted the information (again), after that,
i click in "Fit" then appears in the screem the advise: "there is
something wrong with your math expressions" (or something like that) i ignore
that advise and go on, but the big problem is that the fit appears very
poor!
I have to say that the information that i use to insert the atomic
position, unit cell parameters, was obtained from a Riteveld refinament,
that i performed with the data from a cooper x-ray tube, do i need a data
from a beam line, at synchroton?
Do you have some idea of my problem? Have i make the correct steps?
I'm sorry for my english, i will be very thankful if you answer my
e-mail or give to me someone who can do it!
REGARDS
