DEBYE in **fms**:

The effect of temperature on FMS is approximated by multiplying each free
propagator by
, which gives correct DW
factors for single scattering. The DW factors for multiple
scattering are not exact, but their contribution is reduced both by
thermal factors and by the mean free path. Also if you are running
the **fms** module, then you can only obtain XANES, where this
approximate treatment of thermal effects is probably adequate.

DEBYE in **ff2x**:

The DEBYE card is used to calculate Debye-Waller factors for each
path using the correlated Debye Model. The model is best suited for
homogeneous systems, where it is quite accurate. CAUTION: in
heterogeneous systems the model only gives approximate values which
can easily be off by factors of two or more. If this card is present,
the correlated Debye model Debye-Waller factors will be summed with the
DW factors from the SIG2 card and from the ``list.dat`'
file, if present. Note that the DEBYE card is currently incompatible with the
CFAVERAGE card for options other than the correlated Debye
model (`idwopt` 0). Temperatures are specified in kelvin.

*Debye-Waller factors for Cu at 190K with correlated Debye Model DEBYE 190 315

By default, `idwopt`=0 specifies that the correlated Debye model
is used to calculate EXAFS Debye-Waller factors. Two additional models for
calculating DW factors are available in FEFF8 based on the information
about the harmonic force constants in the material. `idwopt`=1
means the equation of motion (EM) method is used to get Debye-Waller
factors and `idwopt`=2 means the recursion method (RM) which
is an improved correlated Einstein model. Both methods are faster than
molecular dynamics simulations, and the recursion method is much faster
than the equation of motion method. However, the equation of motion method
leads to somewhat more accurate results than the recursion method. These
additional methods seem to be superior to the correlated Debye model in cases
with tetrahedral coordination, such as solid Ge and many biological materials.
Both EM and RM methods need additional input (the force constants) and a
complete description of both is given in Anna Poiarkova's thesis (see the
FEFF project web site, http://feff.phys.washington.edu/feff/)
and in the associated documentation.

* Calculate Debye-Waller factors for Cu at 190K with equation of motion DEBYE 190 0 1