# [CP2K-user] [CP2K:15777] Re: The target temperature cannot be maintained during AIMD simulation process

Lucas Lodeiro eluni... at gmail.com
Fri Jul 23 17:12:34 UTC 2021

```Hello Tingting Zhu,

As far as I know, to correct your errors in EOM, you have to reduce the
time step to 0.5 fs when hydrogen atoms are present and high temperature
(fast dynamics) is applied. Also you have a poor performance in the SCF
cycle. The most important is your convergence criterion, defined by
EPS_SCF. with your current value 1.0E-5 you are having error on the energy
in the order of E-3 E-4, which is very high. REDUCING EPS_SCF and
EPS_DEFAULT probably solve in part these problem. I usually use a relation
(EPS_SCF)^2=EPS_DEFAULT.
Also, your CUTOFF is so low. You have to compute a convergence study first,
to have good SCF results first, and then run the MD. At the forum, some
people says a good guess for cutoff is REL_CUTOFF *
HIGHER_GAUSSIAN_COEFFICIENT, in your case Mg has a hard PP, where the
tighter gaussian has a coefficient of 30.65, then with a REL_CUTOFF=40 you
need a CUTOFF=1200 or higher.

Regards - Lucas Lodeiro

El vie, 23 jul 2021 a las 8:01, 'Tingting Zhu' via cp2k (<
cp... at googlegroups.com>) escribió:

>
> Dear Marcella  Iannuzzi
>
> Ok, thank you! I will learn CP2K as your suggestion.
>
> However, for the problem you pointed "the integral error of the equation
> of motion is large", I still don't know how to solve it? According to my
> current understanding, may I increase the value of EPS_SCF, CUTOFF,
> REL_CUTOFF, and decrease the value of TIMESTEP. Do you think it is
> appropriate?
> For example, ( EPS_DEFAULT 1E-12, EPS_SCF=1.0E*10^6, CUTOFF=350,
> REL_CUTOFF=60, TIMESTEP=0.5)
>
> Sincerely
> Tingting Zhu
>
>
>
>
>
>
>
>
> 在2021年7月23日星期五 UTC+8 下午4:18:42<Marcella Iannuzzi> 写道：
>
>> Dear Tingting Zhu
>>
>> I quickly checked your energy file and indeed you have a serious drift in
>> the total energy,
>> which indicates that the integration of the equations of motion has a
>> large error.
>> If you do not have experience with ab initio MD, I suggest that you learn
>> that first from reference literature.
>> The parameters are adjusted until converged results are obtained and
>> known properties are reproduced.
>>
>> Regards
>> Marcella
>>
>>
>> On Friday, July 23, 2021 at 9:30:06 AM UTC+2 fe... at qq.com wrote:
>>
>>> Dear Marcella Iannuzzi
>>> Since I am a beginner, although I have read a lot of documents about
>>> CP2K, I still lack experience in setting some parameters. In the input
>>> file, could you give me some suggestions about the settings of CUTOFF, SCF,
>>> EPS_SCF? There are 366 atoms in my system, containing Mg, Al, O, and H.
>>> In addition, the input file, out file and corresponding trajectory file
>>> that I calculated before are put in the compressed package below.
>>>
>>> The CP2K version I use is 7.1
>>>
>>> Thank you very much!
>>>
>>>
>>>
>>>
>>> 在2021年7月23日星期五 UTC+8 下午2:49:54<Marcella Iannuzzi> 写道：
>>>
>>>> Dear Tingting Zhu
>>>>
>>>> One possible explanation is that the error in the forces and in the
>>>> integration of the equations of motion is too big.
>>>> Some parameters in the input would indicate that, as too large TIMESTEP
>>>> and EPS_SCF and too low CUTOFF.
>>>> This could be verified from the conservation of the total energy.
>>>> Without more information it is difficult to guess.
>>>>
>>>> Regards
>>>> Marcella
>>>>
>>>> On Friday, July 23, 2021 at 8:34:17 AM UTC+2 fe... at qq.com wrote:
>>>>
>>>>> Dear all,
>>>>>
>>>>> I am new to cp2k, I want to use CP2K's kinetics module to simulate the
>>>>> adsorption of water on the surface of MgAl2O4 (111) at 973K. However, with
>>>>> the increase of simulation time, the temperature keeps increasing, and
>>>>> there is no trend to stablize at the target temperature. My input file is
>>>>> as follows:
>>>>>
>>>>> I also tried to modify the TIMECON parameter to 200fs or 400fs, but
>>>>> this problem always exists. Any idea whats going wrong here?
>>>>>
>>>>> I need your help,  Please do correct me if any information provided
>>>>> seems wrong
>>>>>
>>>>>
>>>>> [image: 200-400 fs.png]
>>>>> [image: 200 fs.png]
>>>>>
>>>>>
>>>>> &GLOBAL
>>>>>   PROJECT MgAl2O4-14W-MD
>>>>>   PRINT_LEVEL LOW
>>>>>   RUN_TYPE MD
>>>>> &END GLOBAL
>>>>>
>>>>> &FORCE_EVAL
>>>>>   METHOD Quickstep
>>>>>   &SUBSYS
>>>>>     &CELL
>>>>>       A    17.33280000     0.00000000     0.00000000
>>>>>       B     0.00000000    20.01420000     0.00000000
>>>>>       C     0.00000000     0.00000000    28.56250000
>>>>>       PERIODIC XYZ #Direction of applied PBC (geometry aspect)
>>>>>     &END CELL
>>>>>     &COORD
>>>>>  Al         0.0000000000        3.3357667100        1.6309187500
>>>>> <(630)%20918-7500>
>>>>>  Al         2.8888577800 <(888)%20857-7800>        8.3393167100
>>>>> <(339)%20316-7100>        1.6309187500 <(630)%20918-7500>
>>>>>  Al         5.7775422200        3.3357667100        1.6309187500
>>>>> <(630)%20918-7500>
>>>>>  Al         8.6664000000        8.3393167100 <(339)%20316-7100>
>>>>>   1.6309187500 <(630)%20918-7500>
>>>>>  Al        11.5552577800        3.3357667100        1.6309187500
>>>>> <(630)%20918-7500>
>>>>> ............
>>>>>     &END COORD
>>>>> #   &VELOCITY #You can set initial atomic velocities in this section
>>>>> #   &END VELOCITY
>>>>>     &KIND Al
>>>>>       ELEMENT Al
>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>>       POTENTIAL GTH-PBE
>>>>>     &END KIND
>>>>>     &KIND Mg
>>>>>       ELEMENT Mg
>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>>       POTENTIAL GTH-PBE
>>>>>     &END KIND
>>>>>     &KIND O
>>>>>       ELEMENT O
>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>>       POTENTIAL GTH-PBE
>>>>>     &END KIND
>>>>>     &KIND H
>>>>>       ELEMENT H
>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>>       POTENTIAL GTH-PBE
>>>>>     &END KIND
>>>>>   &END SUBSYS
>>>>>
>>>>>   &DFT
>>>>>     BASIS_SET_FILE_NAME  /home/room/data/cp2k-7.1.0/data/BASIS_MOLOPT
>>>>>     POTENTIAL_FILE_NAME  /home/room/data/cp2k-7.1.0/data/POTENTIAL
>>>>> #   WFN_RESTART_FILE_NAME MgAl2O4-14W-MD-RESTART.wfn
>>>>>     CHARGE    0 #Net charge
>>>>>     MULTIPLICITY    1 #Spin multiplicity
>>>>>     &QS
>>>>>       EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values
>>>>> such that the energy will be correct up to this value
>>>>>       EXTRAPOLATION ASPC #Extrapolation for wavefunction during e.g.
>>>>> MD. ASPC is default, PS also be used
>>>>>       EXTRAPOLATION_ORDER 3 #Order for PS or ASPC extrapolation. 3 is
>>>>> default
>>>>>     &END QS
>>>>>     &POISSON
>>>>>       PERIODIC XYZ #Direction(s) of PBC for calculating electrostatics
>>>>>       PSOLVER PERIODIC #The way to solve Poisson equation
>>>>>     &END POISSON
>>>>>     &XC
>>>>>       &XC_FUNCTIONAL PBE
>>>>>       &END XC_FUNCTIONAL
>>>>>       &VDW_POTENTIAL
>>>>>         POTENTIAL_TYPE PAIR_POTENTIAL
>>>>>         &PAIR_POTENTIAL
>>>>>           PARAMETER_FILE_NAME dftd3.dat
>>>>>           TYPE DFTD3
>>>>>           REFERENCE_FUNCTIONAL PBE
>>>>>         &END PAIR_POTENTIAL
>>>>>       &END VDW_POTENTIAL
>>>>>     &END XC
>>>>>     &MGRID
>>>>>       CUTOFF 300
>>>>>       REL_CUTOFF 40
>>>>>     &END MGRID
>>>>>     &SCF
>>>>>       MAX_SCF 500 #Maximum number of steps of inner SCF
>>>>>       EPS_SCF 1.0E-05 #Convergence threshold of density matrix of
>>>>> inner SCF
>>>>> #     SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME
>>>>> file as initial guess
>>>>>       &OT
>>>>>         PRECONDITIONER FULL_KINETIC #FULL_SINGLE_INVERSE is also worth
>>>>> to try. FULL_ALL is better but quite expensive for large system
>>>>>         MINIMIZER DIIS #CG is worth to consider in difficult cases
>>>>>         LINESEARCH 2PNT #1D line search algorithm for CG. 2PNT is
>>>>> default, 3PNT is better but more costly. GOLD is best but very expensive
>>>>>       &END OT
>>>>>        &OUTER_SCF
>>>>>          MAX_SCF 500 #Maximum number of steps of outer SCF
>>>>>          EPS_SCF 1.0E-05 #Convergence threshold of outer SCF
>>>>>        &END OUTER_SCF
>>>>>       &PRINT
>>>>>         &RESTART #Use "&RESTART OFF" can prevent generating wfn file
>>>>>           BACKUP_COPIES 0 #Maximum number of backup copies of wfn file
>>>>>         &END RESTART
>>>>>       &END PRINT
>>>>>     &END SCF
>>>>>   &END DFT
>>>>> &END FORCE_EVAL
>>>>>
>>>>> &MOTION
>>>>>   &MD
>>>>>     ENSEMBLE NVT
>>>>>     STEPS 5000
>>>>>     TIMESTEP 1.0 #fs. Decrease it properly for high temperature
>>>>> simulation
>>>>>     TEMPERATURE 973 #Initial and maintained temperature (K)
>>>>>     &THERMOSTAT
>>>>>       TYPE CSVR
>>>>>       &CSVR
>>>>>         TIMECON 200 #Time constant in fs. Smaller/larger results in
>>>>> stronger/weaker temperature coupling
>>>>>       &END CSVR
>>>>>       &DEFINE_REGION
>>>>>         LIST      193..366
>>>>>       &END DEFINE_REGION
>>>>>     &END THERMOSTAT
>>>>>   &END MD
>>>>>   &CONSTRAINT
>>>>>     &FIXED_ATOMS #Set atoms to be fixed
>>>>>       COMPONENTS_TO_FIX XYZ #May also be e.g. Z, XY ...
>>>>>       LIST        1..192
>>>>>
>>>>>     &END FIXED_ATOMS
>>>>>   &END CONSTRAINT
>>>>>   &PRINT
>>>>>     &TRAJECTORY
>>>>>       &EACH
>>>>>         MD     1 #Output frequency of geometry
>>>>>       &END EACH
>>>>>       FORMAT xyz
>>>>>     &END TRAJECTORY
>>>>>     &VELOCITIES
>>>>>       &EACH
>>>>>         MD     1 #Output frequency of velocity
>>>>>       &END EACH
>>>>>     &END VELOCITIES
>>>>>     &RESTART
>>>>>       BACKUP_COPIES 0 #Maximum number of backing up restart file
>>>>>       &EACH
>>>>>         MD 10 #Frequency of updating last restart file
>>>>>       &END EACH
>>>>>     &END RESTART
>>>>>   &END PRINT
>>>>> &END MOTION
>>>>>
>>>>> Thanks in advance!
>>>>>
>>>>> Sincerely
>>>>> Tingting Zhu
>>>>>
>>>>>
>>>>> --
> You received this message because you are subscribed to the Google Groups
> "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to cp... at googlegroups.com.
> To view this discussion on the web visit