Questions about the section Mixing in the XAS calculation
marci
marc... at pci.uzh.ch
Thu Jan 28 13:21:49 UTC 2010
Hi,
At the moment only the direct mixing is possible with XAS
calculations,
g-space mixing in combination with GAPW calculations need some
additional changes that are not implemented yet.
The plan is to have this extension relatively soon.
kind regards
Marcella
On Jan 28, 2:08 pm, zh <vale... at gmail.com> wrote:
> 1). In the manual of cp2k, it mentions that there are a couple of
> optional charge mixing methods for the XAS calculations. However, from
> the source code,i.e., xas_tp_scf.F, it is found that only the
> "DIRECT_P_MIXING" is indeed supported, as shown in followings
> ....
> 421 IF (scf_env%mixing_method.EQ.direct_mixing_nr) THEN
> 422 CALL scf_env_density_mixing(scf_env%p_mix_new,&
> 423 scf_env,scf_env%iter_delta,&
> 424 qs_env=qs_env,diis=diis_step, error=error)
> 425 ENDIF
> ........
>
> Once the other mixing method (e.g., BROYDEN_MIXING, PULAY_MIXING) is
> chosen in the self-consistent calculation of the ground state, the
> self-consistent calculation for the excited state (e.g., DSCF, TP_HH
> calculations) will stop in the first iteration step. This is observed
> in my test calculations. I want to confirm whether the above thing is
> true or not.
>
> 2). If it is true, i.e., only the "DIRECT_P_MIXING" is indeed
> supported for the self-consistent calculation of excited state for XAS
> spectrum, how can we modify the source code to enable other mixing
> methods for XAS calculations? Is it easy do such thing? Actually,
> these charge mixing methods are already implemented in
> "qs_gspace_mixing.F". Wish someone give me some hints.
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