[Pw_forum] What happens at REALLY large ectuwfc?

[Brad Malone]

>start with 'random' or 'atomic+random' initial wavefunctions
>(startingwfc='...'). I didn't find anything wrong with very
>high cutoffs. Occasionally you can end up in the wrong ground
>state, though, especially in highly symmetric cases like the
>Si example you sent.

Hi Paolo. I tried startingwfc='random' and the eigenvalues are now
essentially the same as the 200 Ry calculation.

------------------------------------------------
          k = 0.0000 0.0000 0.0000 (****** PWs)   bands (ev):

    -5.1746   7.0369   7.0369   7.0369

!    total energy              =   -14.59208472 Ry
     Harris-Foulkes estimate   =   -14.59208472 Ry
     estimated scf accuracy    <        3.8E-11 Ry

     The total energy is the sum of the following terms:

     one-electron contribution =     5.58227211 Ry
     hartree contribution      =     1.67255887 Ry
     xc contribution           =    -5.04795092 Ry
     ewald contribution        =   -16.79896478 Ry
     Fock energy 1             =     0.00000000 Ry
     Fock energy 2             =     0.00000000 Ry
     Half Fock energy 2        =     0.00000000 Ry
----------------------------------------------------------------

Thanks,
Brad


On Sun, Jan 24, 2010 at 2:38 PM, Brad Malone <brad.malone at gmail.com> wrote:

> >are you using the latest cvs version? apparently there is a problem
> >with the new symmetrization algorithm that will be fixed ASAP.
>
> The results I posted are from espresso-4.0.5, although I originally saw
> this problem with espresso-4.1.1 in a different system (AlAs on a 2x2x2
> shifted grid).
>
> As for what Lorenzo said, it makes sense with what I'm seeing. The energy
> breakdowns for the 200 Ry and the 2000 Ry cases are shown below:
>
> For 200 Ry:
> --------------------------------
> !    total energy              =   -14.59208467 Ry
>      Harris-Foulkes estimate   =   -14.59208467 Ry
>      estimated scf accuracy    <        3.9E-11 Ry
>
>      The total energy is the sum of the following terms:
>
>      one-electron contribution =     5.58227319 Ry
>      hartree contribution      =     1.67255719 Ry
>      xc contribution           =    -5.04795028 Ry
>      ewald contribution        =   -16.79896478 Ry
>      Fock energy 1             =     0.00000000 Ry
>      Fock energy 2             =     0.00000000 Ry
>      Half Fock energy 2        =     0.00000000 Ry
> -------------------------
> For 2000 Ry:
> -------------------------
> !    total energy              =   -14.11008918 Ry
>      Harris-Foulkes estimate   =   -14.11008918 Ry
>      estimated scf accuracy    <        1.0E-11 Ry
>
>      The total energy is the sum of the following terms:
>
>      one-electron contribution =     6.07256114 Ry
>      hartree contribution      =     1.58024935 Ry
>      xc contribution           =    -4.96393489 Ry
>      ewald contribution        =   -16.79896478 Ry
>      Fock energy 1             =     0.00000000 Ry
>      Fock energy 2             =     0.00000000 Ry
>      Half Fock energy 2        =     0.00000000 Ry
> -------------------
>
> So you can see the one-electron contribution going up and the hartree
> contribution going down as Lorenzo as argued.
>
> Brad
>
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