<s>
FEFF	B-Application
is	O
a	O
software	O
program	O
used	O
in	O
x-ray	B-Library
absorption	O
spectroscopy	O
.	O
</s>
<s>
It	O
contains	O
self-consistent	O
real	O
space	O
multiple-scattering	O
code	O
for	O
simultaneous	O
calculations	O
of	O
x-ray-absorption	O
spectra	O
and	O
electronic	O
structure	O
.	O
</s>
<s>
Output	O
includes	O
extended	O
x-ray-absorption	O
fine	O
structure	O
(	O
EXAFS	O
)	O
,	O
full	O
multiple	O
scattering	O
calculations	O
of	O
various	O
x-ray	B-Library
absorption	O
spectra	O
(	O
XAS	O
)	O
and	O
projected	O
local	O
densities	O
of	O
states	O
(	O
LDOS	O
)	O
.	O
</s>
<s>
The	O
spectra	O
include	O
x-ray	B-Library
absorption	O
near	O
edge	O
structure	O
(	O
XANES	O
)	O
,	O
x-ray	B-Library
natural	O
circular	O
dichroism	O
(	O
XNCD	O
)	O
,	O
and	O
non-resonant	O
x-ray	B-Library
emission	O
spectra	O
.	O
</s>
<s>
Calculations	O
of	O
the	O
x-ray	B-Library
scattering	O
amplitude	O
(	O
Thomson	O
and	O
anomalous	O
parts	O
)	O
and	O
spin	O
dependent	O
calculations	O
of	O
x-ray	B-Library
magnetic	O
circular	O
dichroism	O
(	O
XMCD	O
)	O
and	O
spin	B-General_Concept
polarized	I-General_Concept
x-ray	B-Library
absorption	O
spectra	O
(	O
SPXAS	O
and	O
SPEXAFS	O
)	O
are	O
also	O
possible	O
,	O
but	O
less	O
automated	O
.	O
</s>
<s>
The	O
most	O
recent	O
version	O
of	O
FEFF	B-Application
is	O
FEFF10	O
,	O
released	O
in	O
2020	O
.	O
</s>
<s>
FEFF	B-Application
is	O
used	O
as	O
external	O
program	O
to	O
calculate	O
basic	O
spectra	O
for	O
XANES	O
fitting	O
using	O
FitIt	B-Application
.	O
</s>
