[CP2K-user] Struggling to get SCF Convergence in Cell_Opt run
Marcella Iannuzzi
marci... at gmail.com
Fri Jan 22 08:16:58 UTC 2021
No smearing with 0K does not help.
Smearing needs a finite temperature, can be lower than 500, for instance
300K, not 0K
On Friday, January 22, 2021 at 9:04:31 AM UTC+1 ASSIDUO Network wrote:
> 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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