[CPMD-list] (no subject)

Wed Oct 10 18:23:46 CET 2007

Dear K Dong,

   The total (= Kohn-Sham) energy is POSITIVE before the first iteration - 
that should already ring a bell that something is badly wrong!! Did you 
relax the electronic structure before this job...? Or the geometry is 
completely wrong...

   You can either relax the structure, or if you think that your system is 
correct (did you check that your coordinates are in Bohr, or use the 
keyword 'ANGSTROM'? Is your lattice correct?), like I would guess because 
the EKS soon find positive values, then you can add
   QUENCH BO ELECTRONS
to the input of your first MD job.

   I combination of dt = 5 / mu = 600 is on the limit, it also depends on 
the cut-off energy in your calculation. Nowadays something like 4/500 or 
4/300 (I don't remember if the latter is stable though) sounds more 
fashionable, and like suggested later you might indeed want to deuterate 
your hydrogens, if present in the system.

     Greetings from Paris,

        apsi

PS The typo 'DYNAIMCS' doesn't matter ;)

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   IMPMC, CNRS & Université Pierre et Marie Curie
   Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820

On Wed, 10 Oct 2007, kdong_bj at sina.com wrote:

> Dear every cpmd user,
>   I am studying a mixture of water and aother solvant.
>   After 5ns using classical MD, I pick up a configuration as initial geometry to carry out the CPMD.
>   After optimization of wavefunctions, the molecular dynamic was carried out,  my input file look like as follows,
>    &CPMD
>    MOLECULAR DYNAIMCS CP
>    RESTART WAVEFUNCTIONS COORDINATES LATEST
>    MAXSTEP
>    10000
>    TIMESTEP
>    5.0
>    EMASS
>    600
>     NOSE IONS
>     350.0 3000.0
>     &END
>     ........
>
>
>    My system contains 624 atoms, the DFT is BLYP.
>    but the output file look like as follows,
>   TOTAL INTEGRATED ELECTRONIC DENSITY
     IN G-SPACE =                                      1296.000000
     IN R-SPACE =                                      1296.000000

  (K+E1+L+N+X)           TOTAL ENERGY =         1060.70424073 A.U.
  (K)                  KINETIC ENERGY =         1152.16714712 A.U.
  (E1=A-S+R)     ELECTROSTATIC ENERGY =          623.45349978 A.U.
  (S)                           ESELF =         1633.00373444 A.U.
  (R)                             ESR =          104.08282525 A.U.
  (L)    LOCAL PSEUDOPOTENTIAL ENERGY =         -246.43453910 A.U.
  (N)      N-L PSEUDOPOTENTIAL ENERGY =           71.85023843 A.U.
  (X)     EXCHANGE-CORRELATION ENERGY =         -540.33210550 A.U.
          GRADIENT CORRECTION ENERGY =           -27.19522460 A.U.

        NFI    EKINC   TEMPP           EKS      ECLASSIC          EHAM         DIS    TCPU
          1405.82400  2304.5    1060.70424    1066.65044    1472.47444   0.267E-04   49.31
          2*********  7683.0     362.41271     382.25520    1442.24111   0.378E-03   49.88
          3********* 14286.4    -161.05320    -123.98183    1426.36893   0.175E-02   49.81
          4********* 19178.7    -479.07083    -428.70524    1421.92633   0.480E-02   50.82
          5********* 21004.5    -615.53653    -559.18291    1423.61595   0.964E-02   50.08
          6********* 20588.9    -639.97824    -583.17403    1430.63220   0.158E-01   50.54
          7********* 19201.5    -640.22750    -585.70370    1433.66427   0.224E-01   50.18
          8********* 17441.1    -638.63291    -587.47348    1433.66556   0.289E-01   50.27
          9********* 15586.6    -621.54404    -574.06576    1436.47016   0.349E-01   50.37
         10********* 13990.8    -597.68101    -553.27424    1438.53594   0.403E-01   49.54
         11********* 12777.0    -578.07436    -535.81504    1440.02596   0.452E-01   49.83
         12********* 11812.7    -571.61753    -530.92881    1440.10169   0.498E-01   50.14
         13********* 10988.3    -577.18200    -537.76902    1438.61381   0.540E-01   50.15
         14********* 10240.8    -582.77211    -544.49911    1438.13870   0.579E-01   50.56
         15*********  9584.7    -583.12336    -545.81173    1438.55877   0.613E-01   49.97
         16*********  9040.3    -581.73781    -545.14929    1439.51770   0.643E-01   50.37
>    Originally, I think the timestep is not correct, but when the timestep is increased to 10.0, the NaN ocurred, so I did not know the reasons,
> can you help me?
>

>      Best Regards
>     k.dong
> 
> 2007-08-28 
>
>
>
> K. dong
> Institute of Process Engineering
> Chinese Academy of Sciences
> P. O. BOX 63, Beijing 100080
> The People's Republic of China
> E-mail: dongkun at home.ipe.ac.cn
>           kdong at foxmail.com

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