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12. Appendix F. Changes from previous versions

12.1 Changes from FEFF 6

The most significant change is that LDA atomic code was replaced by Dirac-Fock code. FEFF 7 includes both dipole transitions (l----> l +/-- 1).

The changes have been made for the following cards:

PRINT

FEFF 7.00 will write files phminNN.dat, whenever phaseNN.dat is written, which has real part of phase shifts for l=0,1,2. So, they have reduced information of corresponding phaseNN.dat, which is conveniently arranged in columns for plotting.

XANES

If XANES card is specified, then core hole lifetime is taken into account by convolution with Lorentzian in ff2chi. Otherwise, core hole life time is included into imaginary part of optical potential, as in FEFF 6.10. Minor differences for chi.dat files calculated by two methods in XANES region are expected. The FEFF7 code includes a fully relativistic calculation of atomic cross section.

EXCHANGE

New self energy models are available: a) broadened plasmon model (ixc \gt 10) and b) partly nonlocal model (ixc=5) which calculates for the photoelectron DF exchange term for core electrons and LDA exchange-correlation for valence electrons. Core-valence separation can be easily changed in getorb.f.

New expert user only cards are introduced:

MBCONV

Makes convolution with model excitation spectrum.

JUMPRM

Removes jumps in potentials at muffin tin radii.


Also, we made several adjustments to fix some minor problems reported by FEFF users.

12.2 Changes from FEFF 5.04

We have made some minor changes to the input files and code. For complete descriptions of the new cards and modifications of old ones, see section III. With the exception of POLARIZATION and XANES capabilities, and improved path finder and degeneracy checks, FEFF 6 is nearly identical to FEFF5.

Two cards are no longer recognized. These are:


There are several changes and new options. These are:

CORRECTIONS

Adds real and imaginary part to energy

CRITERIA

The importance criteria are now formulated differently

NEMAX

Max number of energy grid points (replaces KLIMIT)

PCRITERIA

The path finder criteria are now formulated differently

PRINT

Several new options

POTENTIALS

Now has optional labels for unique potentials


XANES spectra, absolute energies and Atomic Background absorption can be calculated with the new option

XANES

For now, please, do not use chiNNNN.dat or feffNNNN.dat files for EXAFS analysis (such as feffit), when XANES card is used.


Polarization dependent feff can be calculated with the help of the following new cards:

POLARIZATION

Specifies polarization vector

ELLIPTICITY

Ellipticity and direction of the incident beam for the elliptical polarization.


FEFF 6.10 adds several new cards, uses a slightly finer k grid internally, and replaces the feff.dat files with one feff.bin to speed execution and reduce disk space.


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