The construction of the interstitial potential and density may be
changed by using this card.
ipot=1 might be useful when only the surroundings of the absorbing
atom are specified in `feff.inp'. irmt and
irav are described only for completeness, and use of nonzero values
is strongly discouraged.
potential index. ipot defines how to
find the interstitial potential. ipot=0 (default): the interstitial
potential is found by averaging over the entire extended cluster in
`feff.inp'. ipot=1 : the interstitial potential is found locally
around the absorbing atom.
also changes how the interstitial potential
is found. irav=0 (default): the equation for V is constructed
at rav=rnrm. irav=1 : at rav=(rmt
irav=2 : at rav=rmt, where rmt is the muffin-tin radius and
rnrm is the Norman radius.
irmt apparently does not exist in the code
irmt=0 (default): Norman prescription for mt radii.
irmt=1 : Matching point prescription for mt radii (do not
the volume per atom normalized
by ratmin (vtot=(volume per atom)/ratmin),
where ratmin is the shortest bond for the absorbing atom. This
quantity defines the total volume (needed to calculate the interstitial
density) of the extended cluster specified in `feff.inp'. If vtot
0 then the total volume is calculated as a sum of Norman sphere volumes.
Otherwise, total volume = nat(vtotratmin),
where nat is the number of atoms in an extended cluster. Thus
vtot=1.0 is appropriate for cubic structures, such as NaCl. The
INTERSTITIAL card may be useful for open systems (e.g. those which have ZnS
* improve interstitial density for ZnS structures.
* vtot = (unit_cell_volume/number_of_atoms_in_unit_cell)/ratmin**3)=1.54
INTERSTITIAL 0 1.54