Hi Ross et al. The answer depends to some extent on which peaks you are talking about. Getting peak positions right requires good scattering potentials (large enuf clusters and l_fms and sometimes fiddling with muffin-tin radii), converged full multiple-scattering calculations (large enuf clusters, large enuf lmax). It may be difficult to get the edge peaks right with the spherical muffin-tin potentials in FEFF. An additional effect is the self-energy, but the Hedin-Lundqvist model often does a good job. You might try using Dirac-Hara for molecular solids. J. Rehr On Mon, 23 Sep 2013, Ross Devol wrote:

Hi everyone,   I am using FEFF to calculate XANES spectra for calcium carbonates, and I am wondering how precisely I should expect the relative peak energies should be consistent with experiments. Is there anything I can do within FEFF to shift peaks relative to each other or to stretch/compress the entire spectrum? I've tried increasing l_fms (or lmax2), which helps some but not enough.   Thank you!

Ross DeVol University of Wisconsin-Madison