Hi feffusers,
> I am investigating the system, BaTiO3. Specifically l am looking at the
> elnes generated by the xanes card. I would like to introduce broadening
> into my calculation as it does not seem to converge, even for very big
> clusters. If l increase Eimag for LDOS , (module two) will this be carried
Do you mean that self-consistency loop does not converge?
If that is the case, then use SCF 4.0 card. In may experience
this typically leads to good potential, while rarely has problem
with convergence. Of course for LDOS and XANES(ELNES) calculation
you might want to use larger radius (e.g. FMS 8.0)
> through to the xanes calculation or is there another way to introduce
> broadening?
No. The Im part in LDOS card is not carried over to XANES calculations.
Use EXCHANGE card to do that (EXCHANGE 0 0 1.0 to add 1 eV Lorentzian
braoadening). This is the best way to introduce broadening, but
you have to rerun starting from the second module. Bruce Ravel
suggested to use CORRECTION 0 1.0. This is faster, since it also makes
Lorentzian broadening but require to rerun only the last module (ff2chi
or CINTROL 0 0 0 0 0 1 ).
> Also, if this is the correct way to introduce broadening and get the
> calculation to converge with smaller clusters, then what would be an
> appropriate value for Eimag?
What convergence are we talking about? SCF loop or convergence
with cluster size?
Matt Newville pointed out that convolution with Voigt function
might be prefereable. If someone has tested FORTRAN routines for
such convolution, I can easily include them. For example,
we can use (CORRECTION 0 1.0 type_conv ), where type_conv=0
for Lorentsian, 1- for Gaussian, 2-for Voigt, etc..
Best wishes
Alex Ankudinov