[CP2K-user] Struggling to get SCF Convergence in Cell_Opt run
ASSIDUO Network
lenardc... at gmail.com
Fri Jan 22 08:04:31 UTC 2021
I'm going to follow your advice, but if I remember correctly, last time I
tried smearing with 0 K, the stimulation ended with an error. If it does it
again, I will ask for some feedback again.
On Friday, January 22, 2021 at 9:59:40 AM UTC+2 Marcella Iannuzzi wrote:
>
>
> Hi
>
> The smearing with finite electronic temperature is needed in order to
> allow convergence of the metallic electronic structure, even if the
> structure is kept a 0K. The number of added MOS depends on the density of
> states around Fermi. Too many states do not hurt, in terms of convergence.
> I just chose a safe number, probably less are also OK, as a lower smearing
> temperature would also work.
> As a functional I took one that I often use. Anyway, I think that adding
> VDW is a good idea.
> All these aspects are more general on electronic structure theory and not
> specific of CP2K. Please read in the literature for better understanding.
> Regards
> Marcella
>
>
> On Friday, January 22, 2021 at 8:37:46 AM UTC+1 ASSIDUO Network wrote:
>
>> I should have added this earlier, the simulation must be performed at 0 K
>> (my supervisor's request), it's a static run. Therefore, I cannot set the
>> temperature to 500 K. Also, why the need for ADDED_MOS=200? In another
>> thread, I was told that ADDED_MOS=100 was too much.
>>
>> Also, why the use of FUNCTIONAL XC_GGA_C_PBE and FUNCTIONAL
>> XC_GGA_X_RPW86? I'm new to CP2K so just want to understand everything
>> better.
>> On Friday, January 22, 2021 at 9:24:10 AM UTC+2 Marcella Iannuzzi wrote:
>>
>>> Hi Lenard,
>>>
>>> I got it converging in 10 iterations.
>>> The outer SCF with diagonalisation is useless, since there is no
>>> preconditioner.
>>> With metals you need to use smearing.
>>> Here are some settings I used:
>>> ADDED_MOS 200
>>> &DIAGONALIZATION T
>>> ALGORITHM STANDARD
>>> &END DIAGONALIZATION
>>> &MIXING T
>>> METHOD BROYDEN_MIXING
>>> ALPHA 0.01
>>> BETA 0.5
>>> NBUFFER 8
>>> &END MIXING
>>> &SMEAR
>>> METHOD FERMI_DIRAC
>>> ELECTRONIC_TEMPERATURE 500
>>> &END SMEAR
>>>
>>> &XC
>>> &XC_FUNCTIONAL
>>> &LIBXC
>>> FUNCTIONAL XC_GGA_X_RPW86
>>> &END LIBXC
>>> &LIBXC
>>> FUNCTIONAL XC_GGA_C_PBE
>>> &END LIBXC
>>> &END XC_FUNCTIONAL
>>>
>>> &VDW_POTENTIAL
>>> POTENTIAL_TYPE NON_LOCAL
>>> &NON_LOCAL
>>> CUTOFF 300
>>> TYPE RVV10
>>> ## VERBOSE_OUTPUT
>>> KERNEL_FILE_NAME ${data}/rVV10_kernel_table.dat
>>> &END NON_LOCAL
>>> &END VDW_POTENTIAL
>>> &END XC
>>>
>>> The results:
>>>
>>> Step Update method Time Convergence Total energy
>>> Change
>>>
>>> ------------------------------------------------------------------------------
>>> 1 NoMix/Diag. 0.10E-01 20.0 0.51067755 -133.2796876462
>>> -1.33E+02
>>> 2 Broy./Diag. 0.10E-01 17.6 0.00064724 -136.0334243526
>>> -2.75E+00
>>> 3 Broy./Diag. 0.10E-01 17.5 0.03257808 -134.7316158415
>>> 1.30E+00
>>> 4 Broy./Diag. 0.10E-01 17.7 0.00019866 -133.0666478987
>>> 1.66E+00
>>> 5 Broy./Diag. 0.10E-01 17.6 0.00228816 -133.1462861174
>>> -7.96E-02
>>> 6 Broy./Diag. 0.10E-01 17.6 0.00032933 -133.1654553845
>>> -1.92E-02
>>> 7 Broy./Diag. 0.10E-01 17.6 0.00000406 -133.1816175525
>>> -1.62E-02
>>> 8 Broy./Diag. 0.10E-01 17.7 0.00009047 -133.1825852315
>>> -9.68E-04
>>> 9 Broy./Diag. 0.10E-01 17.6 0.00000504 -133.1830490186
>>> -4.64E-04
>>> 10 Broy./Diag. 0.10E-01 17.6 0.00000031 -133.1828944498
>>> 1.55E-04
>>>
>>> *** SCF run converged in 10 steps ***
>>>
>>>
>>> Electronic density on regular grids: -44.0000000000
>>> 0.0000000000
>>> Core density on regular grids: 43.9999999999
>>> -0.0000000001
>>> Total charge density on r-space grids: -0.0000000001
>>> Total charge density g-space grids: -0.0000000001
>>>
>>> Overlap energy of the core charge distribution:
>>> 0.00000001219968
>>> Self energy of the core charge distribution:
>>> -231.41335460772382
>>> Core Hamiltonian energy:
>>> 74.19344628639691
>>> Hartree energy:
>>> 45.27318657026385
>>> Exchange-correlation energy:
>>> -21.30000506759340
>>> Dispersion energy:
>>> 0.06400174824714
>>> Electronic entropic energy:
>>> -0.00016939092888
>>> Fermi energy:
>>> 0.34714684334798
>>>
>>> Total energy:
>>> -133.18289444982969
>>>
>>>
>>>
>>> Regards
>>> Marcella
>>>
>>> On Friday, January 22, 2021 at 6:48:12 AM UTC+1 ASSIDUO Network wrote:
>>>
>>>> Hi there everyone, hope you've had a great week.
>>>>
>>>> I've been trying to run a cell optimization of bulk Au, and I am using
>>>> the attached input file, but I'm not getting an inner loop SCF convergence.
>>>> I've made many small changes, such as including/excluding OUTER_SCF,
>>>> changing the SCF convergence criterion, changing the number of cell
>>>> optimization steps, changing the number of KPoints and changing the mixing
>>>> method. Nothing has worked. I haven't tried a combination of the above
>>>> though.
>>>>
>>>> Do you perhaps have any suggestions to me on how to get convergence?
>>>> Furthermore, I would also appreciate some tips to speed up my simulations
>>>> (settings/flags) wise.
>>>>
>>>> Thanks in advance,
>>>> Lenard
>>>>
>>>>
>>>>
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