# CORRECTIONS

Useful

CORRECTIONS vrcorr vicorr

The real energy shift vrcorr moves E0 in the final $\chi(k)\,\!$ and the imaginary energy shift vicorr adds broadening to the result. The real energy shift is useful to correct the error in FEFF’s Fermi level estimate and the imaginary part can be used to correct for experimental resolution or errors in the core-hole lifetime. This error in the Fermi level is typically about 1 eV with self-consistent calculations and about 3 eV with overlapped atom potentials. The imaginary energy is typically used to correct for instrument broadening or as a correction to the mean free path calculated by feff. This affects only the modnule FF2CHI, which combines the results in all of the ‘feffNNNN.dat’ files. This card is useful in fitting loops because you can simply make such energy corrections and see the results without redoing the entire XAFS parameter calculation. CAUTION: the results are not as accurate as those obtained with the EXCHANGE card. Both energies are in eV.

* Reduce E0 by 3.0 eV and add 1 eV of broadening (full width)
* This will only affect module 4, ff2chi
CORRECTIONS 3.0 1.0 real shift, imag shift