Hi Igor (and Anatoly),
I could be wrong, but if I recall correctly a self-consistent
field calculation by FEFF8 [i]calculates[/i] what it thinks E0 should
be relative to the derivative peak, and then uses that as the
"new" baseline E0. In other words, a d-E0 found via the SCF
FEFF calculation is relative to a different starting point! You can
figure out what the SCF FEFF calculation assigned as the baseline E0
by looking at the file xmu.dat and seeing what energy k = 0
corresponds to.
--Scott Calvin
Sarah Lawrence College
The second problem is of philosophical nature and more important than
the first one because its clarification will provide the answer for
the first problem and also some peace of mind. I do not understand why
the E0 corrections (d_E0's) are so different. The fact that the
correction obtained from SCF calculation is larger (and apparently
worse) than that obtained from the nSCF calculation (absolute values)
seems counter intuitive to me. The E0 value I picked for background
subtraction is 8989 eV, and applying the corrections, I find an edge
energy of 8990.1 eV and 8981.5 eV respectively. This second
value falls in the pre-edge region, pretty much on the 1s-3d
transition bump. Despite the evidences, I tend to trust the SCF's d_E0
value the most but would like to understand the physics (or lack of)
behind the different feff calculations!
I apologize if I bored you with unecessary details! Thank you very
much for your attention and willingness to help! I really appreciate
it!
Best regards,
Igor