[CP2K:4024] Energy conservation NVT/NVE simulation

garold g.murd... at gmail.com
Wed Sep 12 10:38:09 UTC 2012


Hi Alberto,

May I suggest use of smoothing, i.e., including a section:

       &XC_GRID
         XC_SMOOTH_RHO  NN10  ! (or NN50)
         XC_DERIV  SPLINE2_SMOOTH
       &END XC_GRID

You can also see the previous discussion on this forum:

https://groups.google.com/forum/?hl=it&fromgroups=#!topic/cp2k/dc4kzNqNw-8

where a similar discussion occurred.

Best,
Garold



On Tuesday, September 11, 2012 12:35:42 PM UTC+3, albe... at virgilio.it 
wrote:
>
> Hi,
>
> for the restart I used the last restart file of the previous run, 
> modifying the parameters in $QS or $SCF to test the new ones.
> I observed a drift also for NVE even if most of the tests have been done 
> for NVT.
> I will carry out more tests for NVE to reduce the number of variables and 
> avoid also the problem of thermostat setting.
>
> About the drift, after few ps it is about 10^-3 au, depending on the 
> simulations. 
> Changing the parameters to increase the accuracy, in some cases I observed 
> no drift but sudden jumps in the total energy.
>
> I will keep you updated about further NVE tests.
> Thanks
>
> alberto
>
> Il giorno martedì 11 settembre 2012 11:04:00 UTC+2, jgh ha scritto:
>>
>> Hi 
>>
>> it is difficult to give good advice without more information. 
>>
>> Possible problems might be: 
>>
>> - Restarts: do you correctly restart all variables 
>> - Thermostat: I don't know if the setting you have is reasonable 
>>               and adequate for this timestep. 
>>               Do you see a drift also for NVE? 
>> - How big is the drift and how long is your trajectory? 
>>
>> regards 
>>
>> Juerg 
>>
>> -------------------------------------------------------------- 
>> Juerg Hutter                         Phone : ++41 44 635 4491 
>> Physical Chemistry Institute   FAX   : ++41 44 635 6838 
>> University of Zurich               E-mail:  hut... at pci.uzh.ch 
>> Winterthurerstrasse 190 
>> CH-8057 Zurich, Switzerland 
>> --------------------------------------------------------------- 
>>
>> -----cp... at googlegroups.com wrote: ----- 
>> To: cp... at googlegroups.com 
>> From: "albe... at virgilio.it" 
>> Sent by: cp... at googlegroups.com 
>> Date: 09/11/2012 10:06AM 
>> Subject: Re: [CP2K:4024] Energy conservation NVT/NVE simulation 
>>
>> Dear Juerg, 
>>
>> thank you very much. 
>>
>> I changed the functional to BLYP and I used ASPC interpolator. 
>> I carried out different tests where I tried different values of the 
>> EXTRAPOLATION_ORDER (up to 6), I increased the EPS_SCF and used defaults 
>> for most of the other parameters. 
>> Unfortunately, I still observe either drifts or jumps in the total 
>> energy. 
>>
>> I think that there is still a problem in the input, reported below. 
>>
>> Many thanks for your help. 
>>
>> Alberto  
>>
>> ************ 
>>
>> &FORCE_EVAL 
>>   METHOD QS 
>>   &DFT 
>>     BASIS_SET_FILE_NAME GTH_BASIS_SETS 
>>     POTENTIAL_FILE_NAME GTH_POTENTIALS 
>>     &MGRID 
>>       CUTOFF 300 
>>       REL_CUTOFF 40 
>>     &END MGRID 
>>     &QS 
>>       EPS_DEFAULT 1.0E-12 
>>       WF_INTERPOLATION ASPC 
>>       EXTRAPOLATION_ORDER 3 
>>     &END QS 
>>     &SCF 
>>       SCF_GUESS ATOMIC 
>>       EPS_SCF 1.0E-6 
>>       &OT T 
>>       &END OT 
>>       &PRINT 
>>         &RESTART OFF 
>>         &END 
>>       &END 
>>     &END SCF 
>>     &XC 
>>       &XC_FUNCTIONAL BLYP 
>>       &END XC_FUNCTIONAL 
>>     &END XC 
>>     &PRINT 
>>       &MOMENTS MEDIUM 
>>       &END 
>>     &END PRINT 
>>   &END DFT 
>>   &SUBSYS 
>>     &CELL 
>>       ABC 9.8528 9.8528 9.8528 
>>     &END CELL 
>>     # 32 H2O (TIP5P,1bar,300K) a = 9.8528 
>>     &COORD 
>>    O       2.280398       9.146539       5.088696 
>>    O       1.251703       2.406261       7.769908 
>>    O       1.596302       6.920128       0.656695 
>>    O       2.957518       3.771868       1.877387 
>>    O       0.228972       5.884026       6.532308 
>>    O       9.023431       6.119654       0.092451 
>>    O       7.256289       8.493641       5.772041 
>>    O       5.090422       9.467016       0.743177 
>>    O       6.330888       7.363471       3.747750 
>>    O       7.763819       8.349367       9.279457 
>>    O       8.280798       3.837153       5.799282 
>>    O       8.878250       2.025797       1.664102 
>>    O       9.160372       0.285100       6.871004 
>>    O       4.962043       4.134437       0.173376 
>>    O       2.802896       8.690383       2.435952 
>>    O       9.123223       3.549232       8.876721 
>>    O       1.453702       1.402538       2.358278 
>>    O       6.536550       1.146790       7.609732 
>>    O       2.766709       0.881503       9.544263 
>>    O       0.856426       2.075964       5.010625 
>>    O       6.386036       1.918950       0.242690 
>>    O       2.733023       4.452756       5.850203 
>>    O       4.600039       9.254314       6.575944 
>>    O       3.665373       6.210561       3.158420 
>>    O       3.371648       6.925594       7.476036 
>>    O       5.287920       3.270653       6.155080 
>>    O       5.225237       6.959594       9.582991 
>>    O       0.846293       5.595877       3.820630 
>>    O       9.785620       8.164617       3.657879 
>>    O       8.509982       4.430362       2.679946 
>>    O       1.337625       8.580920       8.272484 
>>    O       8.054437       9.221335       1.991376 
>>    H       1.762019       9.820429       5.528454 
>>    H       3.095987       9.107088       5.588186 
>>    H       0.554129       2.982634       8.082024 
>>    H       1.771257       2.954779       7.182181 
>>    H       2.112148       6.126321       0.798136 
>>    H       1.776389       7.463264       1.424030 
>>    H       3.754249       3.824017       1.349436 
>>    H       3.010580       4.524142       2.466878 
>>    H       0.939475       5.243834       6.571945 
>>    H       0.515723       6.520548       5.877445 
>>    H       9.852960       6.490366       0.393593 
>>    H       8.556008       6.860063      -0.294256 
>>    H       7.886607       7.941321       6.234506 
>>    H       7.793855       9.141028       5.315813 
>>    H       4.467366       9.971162       0.219851 
>>    H       5.758685      10.102795       0.998994 
>>    H       6.652693       7.917443       3.036562 
>>    H       6.711966       7.743594       4.539279 
>>    H       7.751955       8.745180      10.150905 
>>    H       7.829208       9.092212       8.679343 
>>    H       8.312540       3.218330       6.528858 
>>    H       8.508855       4.680699       6.189990 
>>    H       9.742249       1.704975       1.922581 
>>    H       8.799060       2.876412       2.095861 
>>    H       9.505360       1.161677       6.701213 
>>    H       9.920117      -0.219794       7.161006 
>>    H       4.749903       4.186003      -0.758595 
>>    H       5.248010       5.018415       0.403676 
>>    H       3.576065       9.078451       2.026264 
>>    H       2.720238       9.146974       3.273164 
>>    H       9.085561       4.493058       9.031660 
>>    H       9.215391       3.166305       9.749133 
>>    H       1.999705       2.060411       1.927796 
>>    H       1.824184       0.564565       2.081195 
>>    H       7.430334       0.849764       7.438978 
>>    H       6.576029       1.537017       8.482885 
>>    H       2.415851       1.576460       8.987338 
>>    H       2.276957       0.099537       9.289499 
>>    H       1.160987       1.818023       4.140602 
>>    H       0.350256       2.874437       4.860741 
>>    H       5.768804       2.638450       0.375264 
>>    H       7.221823       2.257514       0.563730 
>>    H       3.260797       5.243390       5.962382 
>>    H       3.347848       3.732214       5.988196 
>>    H       5.328688       9.073059       5.982269 
>>    H       5.007063       9.672150       7.334875 
>>    H       4.566850       6.413356       3.408312 
>>    H       3.273115       7.061666       2.963521 
>>    H       3.878372       7.435003       6.843607 
>>    H       3.884673       6.966316       8.283117 
>>    H       5.918240       3.116802       5.451335 
>>    H       5.355924       2.495093       6.711958 
>>    H       5.071858       7.687254      10.185667 
>>    H       6.106394       7.112302       9.241707 
>>    H       1.637363       5.184910       4.169264 
>>    H       0.427645       4.908936       3.301903 
>>    H       9.971698       7.227076       3.709104 
>>    H      10.647901       8.579244       3.629806 
>>    H       8.046808       5.126383       2.213838 
>>    H       7.995317       4.290074       3.474723 
>>    H       1.872601       7.864672       7.930401 
>>    H       0.837635       8.186808       8.987268 
>>    H       8.314696      10.115534       2.212519 
>>    H       8.687134       8.667252       2.448452 
>>     &END COORD 
>>     &KIND H 
>>       BASIS_SET TZV2P-GTH 
>>       POTENTIAL GTH-BLYP-q1 
>>     &END KIND 
>>     &KIND O 
>>       BASIS_SET TZV2P-GTH 
>>       POTENTIAL GTH-BLYP-q6 
>>     &END KIND 
>>   &END SUBSYS 
>> &END FORCE_EVAL 
>> &GLOBAL 
>>   PROJECT H2O-32 
>>   RUN_TYPE MD 
>>   PRINT_LEVEL MEDIUM 
>>   &TIMINGS 
>>      THRESHOLD 0.000001 
>>   &END 
>> &END GLOBAL 
>> &MOTION 
>>   &MD 
>>     ENSEMBLE NVT 
>>     STEPS 30000 
>>     TIMESTEP 0.5 
>>     TEMPERATURE 300.0 
>>     &THERMOSTAT 
>>       TYPE CSVR 
>>       &CSVR 
>>         TIMECON 100.0 
>>       &END CSVR 
>>     &END THERMOSTAT 
>>   &END MD 
>>   &PRINT 
>>     &VELOCITIES LOW 
>>     &END 
>>   &END PRINT 
>> &END MOTION 
>>
>> ************** 
>>
>>
>> Il giorno mercoledì 5 settembre 2012 09:56:16 UTC+2, jgh ha scritto:Hi 
>>   
>> the main problem is 
>>   
>>      &QS 
>>       EPS_DEFAULT 1.0E-12 
>>       WF_INTERPOLATION PS 
>>       EXTRAPOLATION_ORDER 3 
>>     &END QS 
>>   
>> change to WF_INTERPOLATION ASPC (the default) and maybe 
>> increase the EXTRAPOLATION_ORDER slightly. 
>> See   
>> J. Hutter, Car-Parrinello molecular dynamics 
>> Wiley Interdisciplinary Reviews: Computational Molecular Science 2 (4) , 
>> pp. 604-612   
>> for an explanation. 
>>   
>> You should also change to a more reasonable DFT functional. 
>> LDA (PADE) will lead to an extremly overstructured system. 
>> See   
>> J. Schmidt et al.,   
>> Isobaric-isothermal molecular dynamics simulations utilizing density 
>> functional theory: An assessment of the structure and density of water at 
>> near-ambient conditions 
>> Journal of Physical Chemistry B Volume 113, Issue 35, 3 September 2009, 
>> Pages 11959-11964 
>>   
>> regards 
>>   
>> Juerg 
>>   
>> -------------------------------------------------------------- 
>> Juerg Hutter                         Phone : ++41 44 635 4491 
>> Physical Chemistry Institute   FAX   : ++41 44 635 6838 
>> University of Zurich               E-mail:  hut... at pci.uzh.ch 
>> Winterthurerstrasse 190 
>> CH-8057 Zurich, Switzerland 
>> --------------------------------------------------------------- 
>>   
>> -----cp... at googlegroups.com wrote: ----- 
>> To: cp... at googlegroups.com 
>> From: "albe... at virgilio.it"   
>> Sent by: cp... at googlegroups.com 
>> Date: 09/05/2012 09:44AM 
>> Subject: [CP2K:4010] Energy conservation NVT/NVE simulation 
>>   
>> Dear all, 
>>   
>> I'm carrying out some tests to reproduce the VDOS of water and I used as 
>> starting points the input files 'H2O-32.inp' and 'H2O-64.inp' in 
>> tests/QS/benchmark directory. 
>>   
>> In both cases I ran a NVT simulation at 300K for 15 ps followed by an NVE 
>> simulation on the equilibrated system. 
>>   
>> I'm puzzled about the results in the energies: in both NVT and NVE  the 
>> plot of 
>> "Cons Qty" show a constant and linear drift while temperature, kinetic 
>> and 
>> potential energy are equilibrated and stable. 
>>   
>> Since "Cons Qty" should be conserved and this is not the case I think 
>> that 
>> there are some problems in the setup of the simulation. 
>> I did not modify the parameters of the benchmark inputs but I just added 
>> the 
>> thermostat section in NVT and I modified only the printing option. 
>>   
>> Thank you very much for your help and suggestions, 
>>   
>> Alberto 
>>   
>>     
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>
>
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