[CP2K-user] [CP2K:12769] Reevaluating energy in geometry optimization

e khodayar e.khod... at gmail.com
Mon Jan 13 09:48:28 UTC 2020

```Thanks for your reply.

On Sun, Jan 12, 2020 at 1:31 AM Patrick Gono <patri... at gmail.com> wrote:

> Dear Khodayar,
>
> The reevaluation of the energy at the end of the optimization might yield
> a different total energy value if your calculation is not converged. If
> that is the case, you might choose more stringent values for EPS_SCF inside
> the SCF subsection, which governs the convergence of the SCF loop, and
> EPS_DEFAULT, which is tied to the numerical accuracy of your calculation.
> From the excerpt you provide, I see that the energy changed by 2.71E-05
> Hartree, or nearly one meV, in the last iteration before convergence.
> That's rather a lot, and hence I'd advise you to decrease EPS_SCF to, say,
> 1.0E-6.
>
> However, in the end, the two values of total energy differ by less than
> 0.08 meV. For most intents and purposes, that's identical, and you can
> choose whichever.
>
> Yours sincerely,
> Patrick Gono
>
> On Sun, 12 Jan 2020 at 08:09, e khodayar <e.khod... at gmail.com> wrote:
>
>> Hi,
>> In the main output file geometry optimization,  at the end of  geometry
>> optimisation step, I have the following information:
>>  --------  Informations at step =    53 ------------
>>   Optimization Method        =                   CG
>>   Total Energy               =       -94.0112708604
>>   Real energy change         =        -0.0000036472
>>   Decrease in energy         =                  YES
>>   Used time                  =              343.953
>>
>>   Convergence check :
>>   Max. step size             =         0.0006162087
>>   Conv. limit for step size  =         0.0010000000
>>   Convergence in step size   =                  YES
>>   RMS step size              =         0.0002737159
>>   Conv. limit for RMS step   =         0.0010000000
>>   Convergence in RMS step    =                  YES
>>   Max. gradient              =         0.0005305121
>>   Conv. limit for gradients  =         0.0010000000
>>   Conv. in gradients         =                  YES
>>   RMS gradient               =         0.0002356500
>>   Conv. limit for RMS grad.  =         0.0010000000
>>   Conv. in RMS gradients     =                  YES
>>  ---------------------------------------------------
>>
>>
>>  *******************************************************************************
>>  ***                    GEOMETRY OPTIMIZATION COMPLETED
>>     ***
>>
>>  *******************************************************************************
>>
>>                     Reevaluating energy at the minimum
>>
>>  Number of electrons:
>>      68
>>  Number of occupied orbitals:
>>      34
>>  Number of molecular orbitals:
>>     34
>>
>>  Number of orbital functions:
>>     232
>>  Number of independent orbital functions:
>>     232
>>
>>  Extrapolation method: ASPC
>>
>>
>>  SCF WAVEFUNCTION OPTIMIZATION
>>
>>   Step     Update method      Time    Convergence         Total energy
>> Change
>>
>> ------------------------------------------------------------------------------
>>      1 Pulay/Diag. 0.50E+00    3.7     0.00001087       -94.0112708604
>> -9.40E+01
>>      2 Pulay/Diag. 0.50E+00    4.7     0.00001294       -94.0112951749
>> -2.43E-05
>>      3 Pulay/Diag. 0.50E+00    4.3     0.00000783       -94.0112680643
>> 2.71E-05
>>
>>   *** SCF run converged in     3 steps ***
>>
>>
>>   Electronic density on regular grids:        -67.9999999983
>> 0.0000000017
>>   Core density on regular grids:               68.0000000001
>> 0.0000000001
>>   Total charge density on r-space grids:        0.0000000017
>>   Total charge density g-space grids:           0.0000000017
>>
>>   Overlap energy of the core charge distribution:
>>  0.00000565490189
>>   Self energy of the core charge distribution:
>>  -223.82607238936723
>>   Core Hamiltonian energy:
>>  69.37181702794591
>>   Hartree energy:
>> 89.86177654697752
>>   Exchange-correlation energy:
>> -29.41879490480421
>>
>>   Total energy:
>>  -94.01126806434611
>>
>>  ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):
>> -94.011268064346112
>>
>> Now my question is:
>> Which total energy i have to use for my data?and why this two total
>> energy that with yellow color is different?
>> Thanks in advance.
>>
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