[CPMD-list] EHAM decreases in NVE MD

Ari P Seitsonen ari.p.seitsonen at iki.fi
Wed Apr 11 13:38:34 CEST 2007


Dear Liu(?),

   Apparently the 30 degrees is too small for your system in the beginning: 
You see that towards the end of this run the system is equilibrating. 
Since you did not optimise the geometry in the beginning the atomic 
coordinates are probably not at equilibrium, thus in the beginning of the 
MD the dynamics needs time to adjust. The magnitude of the fluctuations in 
the instantaneous temperature depend on the size of the system, how far 
you are from the equilibrium, ... Setting the threshould for rescaling of 
the temperature too small usually is counterproductive. As a rule of thumb 
the magnitude of fluctuations is sqrt[2/(3*N)]*T_average, and setting the 
threshould at about twice this value would give a nice initial guess. 
However, this is assuming that your system is already close to the 
structural equilibrium.

   Summa summarum, I don't see big problems at the end of your job; please 
remember that your system probably needs picoseconds to equilibrate, even 
if not more.

     Greetings from Sunny Paris,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   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, 11 Apr 2007, liu liuxiandong wrote:

> Dear all,
>
> I performed NVE CP MD to a mineral phase. I have optimized the wavefunctions
> to 1.0d-6 and then set the following in the input file,
>
> TEMPCONTROL IONS
> 400.0 30.0
>
> But I find the 400.0 K is the lower limit during the MD run and the EHAM
> decreases.
> I guess that the decreasing EHAM was because some hydroxyl groups in the
> input stucture are a little far away from the equilibrium positions. Then ,
> is this output result normal  ? And is there some quicker way to attain the
> EHAM conservation ? Thanks so much.
>
> The following is part of the output.
>
>
>
>      NFI    EKINC   TEMPP           EKS      ECLASSIC      EHAM         DIS    TCPU
>        1  0.00108   387.0    -849.81895    -849.67005    -849.66897   0.488E-05   15.66
>        2  0.00913   400.0    -849.81561    -849.66172    -849.65259   0.190E-04   15.65
>        3  0.02005   374.5    -849.81697    -849.67288    -849.65282   0.433E-04   15.62
>        4  0.02715   400.0    -849.82005    -849.66616    -849.63901   0.769E-04   15.68
>        5  0.02971   400.5    -849.82281    -849.66872    -849.63901   0.122E-03   15.62
>        6  0.02944   407.2    -849.82512    -849.66845    -849.63901   0.179E-03   15.65
>        7  0.02754   417.6    -849.82719    -849.66652    -849.63898   0.247E-03   15.65
>        8  0.02516   429.6    -849.82942    -849.66413    -849.63897   0.327E-03   15.62
>        9  0.02334   400.0    -849.83199    -849.67809    -849.65475   0.421E-03   15.62
>       10  0.02215   410.2    -849.83471    -849.67690    -849.65475   0.523E-03   15.61
>       11  0.02143   419.9    -849.83777    -849.67620    -849.65477   0.638E-03   15.68
>       12  0.02135   428.5    -849.84099    -849.67612    -849.65477   0.767E-03   15.66
>       13  0.02190   400.0    -849.84431    -849.69041    -849.66852   0.910E-03   15.68
>       14  0.02250   406.9    -849.84758    -849.69101    -849.66851   0.106E-02   15.63
>       15  0.02286   414.7    -849.85091    -849.69137    -849.66851   0.123E-02   15.69
>       16  0.02323   422.5    -849.85430    -849.69175    -849.66852   0.141E-02   15.60
>       17  0.02368   400.0    -849.85774    -849.70384    -849.68016   0.160E-02   15.64
>       18  0.02394   408.3    -849.86118    -849.70410    -849.68017   0.181E-02   15.64
>       19  0.02386   417.5    -849.86467    -849.70402    -849.68016   0.203E-02   15.66
>       20  0.02374   427.1    -849.86821    -849.70390    -849.68017   0.227E-02   15.64
>       21  0.02370   400.0    -849.87178    -849.71788    -849.69418   0.253E-02   15.66
>       22  0.02350   409.5    -849.87522    -849.71768    -849.69418   0.279E-02   15.65
>       23  0.02311   419.6    -849.87872    -849.71729    -849.69418   0.307E-02   15.65
>       24  0.02287   429.5    -849.88231    -849.71705    -849.69418   0.337E-02   15.67
>       25  0.02295   400.0    -849.88594    -849.73204    -849.70909   0.369E-02   15.63
>       26  0.02295   408.9    -849.88937    -849.73205    -849.70910   0.402E-02   15.67
>       27  0.02267   418.4    -849.89273    -849.73176    -849.70909   0.436E-02   15.62
>       28  0.02246   427.5    -849.89604    -849.73156    -849.70909   0.472E-02   15.63
>       29  0.02259   400.0    -849.89933    -849.74543    -849.72284   0.509E-02   15.66
>       30  0.02276   407.8    -849.90250    -849.74561    -849.72285   0.547E-02   15.64
>       31  0.02274   416.0    -849.90565    -849.74559    -849.72285   0.587E-02   15.65
>       32  0.02282   423.8    -849.90875    -849.74567    -849.72285   0.628E-02   15.74
>       33  0.02313   400.0    -849.91172    -849.75782    -849.73469   0.672E-02   15.71
>       34  0.02333   406.7    -849.91449    -849.75802    -849.73469   0.715E-02   15.63
>       35  0.02326   413.9    -849.91718    -849.75795    -849.73469   0.760E-02   15.66
>       36  0.02326   420.8    -849.91983    -849.75794    -849.73468   0.806E-02   15.63
>       37  0.02352   427.0    -849.92248    -849.75822    -849.73469   0.854E-02   15.68
>       38  0.02394   400.0    -849.92506    -849.77116    -849.74722   0.903E-02   15.67
>       39  0.02420   405.8    -849.92755    -849.77142    -849.74722   0.952E-02   15.63
>       40  0.02415   412.3    -849.93000    -849.77137    -849.74723   0.100E-01   15.68
>       41  0.02407   418.6    -849.93235    -849.77129    -849.74722   0.105E-01   15.65
>       42  0.02422   424.4    -849.93470    -849.77143    -849.74721   0.111E-01   15.62
>       43  0.02466   429.6    -849.93717    -849.77187    -849.74721   0.116E-01   15.61
>       44  0.02524   400.0    -849.93972    -849.78583    -849.76059   0.121E-01   15.64
>       45  0.02545   405.7    -849.94211    -849.78603    -849.76058   0.127E-01   15.69
>       46  0.02524   412.5    -849.94453    -849.78581    -849.76057   0.132E-01   15.62
>       47  0.02508   419.6    -849.94708    -849.78565    -849.76057   0.138E-01   15.62
>       48  0.02518   426.2    -849.94974    -849.78575    -849.76057   0.143E-01   15.65
>       49  0.02546   400.0    -849.95251    -849.79861    -849.77315   0.149E-01   15.66
>       50  0.02555   407.0    -849.95528    -849.79870    -849.77315   0.154E-01   15.68
>       51  0.02533   415.1    -849.95818    -849.79848    -849.77315   0.160E-01   15.67
>       52  0.02520   423.3    -849.96122    -849.79835    -849.77315   0.165E-01   15.63
>       53  0.02534   400.0    -849.96439    -849.81049    -849.78515   0.171E-01   15.62
>       54  0.02544   408.1    -849.96760    -849.81059    -849.78515   0.176E-01   15.74
>       55  0.02533   417.1    -849.97097    -849.81048    -849.78515   0.182E-01   15.62
>       56  0.02532   426.3    -849.97449    -849.81047    -849.78515   0.188E-01   15.69
>       57  0.02557   400.0    -849.97817    -849.82427    -849.79870   0.193E-01   15.64
>       58  0.02569   409.2    -849.98183    -849.82439    -849.79870   0.199E-01   15.67
>       59  0.02550   419.7    -849.98566    -849.82420    -849.79870   0.205E-01   15.67
>       60  0.02538   400.0    -849.98963    -849.83573    -849.81036   0.210E-01   15.70
>       61  0.02526   410.5    -849.99356    -849.83561    -849.81035   0.216E-01   15.68
>       62  0.02508   421.6    -849.99766    -849.83544    -849.81036   0.222E-01   15.62
>       63  0.02501   400.0    -850.00180    -849.84791    -849.82290   0.227E-01   15.67
>       64  0.02490   410.6    -850.00578    -849.84778    -849.82288   0.233E-01   15.63
>       65  0.02475   421.7    -850.00989    -849.84763    -849.82288   0.239E-01   15.69
>       66  0.02486   400.0    -850.01416    -849.86026    -849.83540   0.245E-01   15.64
>       67  0.02495   410.4    -850.01824    -849.86036    -849.83540   0.251E-01   15.70
>       68  0.02482   421.1    -850.02223    -849.86021    -849.83539   0.257E-01   15.70
>       69  0.02483   400.0    -850.02625    -849.87235    -849.84752   0.263E-01   15.64
>       70  0.02491   409.9    -850.03015    -849.87243    -849.84752   0.270E-01   15.67
>       71  0.02487   420.2    -850.03406    -849.87239    -849.84752   0.276E-01   15.60
>       72  0.02493   400.0    -850.03793    -849.88403    -849.85910   0.283E-01   15.63
>       73  0.02489   409.4    -850.04151    -849.88398    -849.85909   0.289E-01   15.65
>       74  0.02474   419.0    -850.04505    -849.88383    -849.85909   0.296E-01   15.63
>       75  0.02471   428.1    -850.04852    -849.88380    -849.85910   0.303E-01   15.71
>       76  0.02488   400.0    -850.05186    -849.89796    -849.87308   0.310E-01   15.60
>       77  0.02494   408.0    -850.05498    -849.89801    -849.87307   0.317E-01   15.65
>       78  0.02473   416.5    -850.05808    -849.89781    -849.87308   0.325E-01   15.63
>       79  0.02458   424.7    -850.06105    -849.89766    -849.87308   0.333E-01   15.64
>       80  0.02468   400.0    -850.06389    -849.90999    -849.88532   0.340E-01   15.66
>       81  0.02470   406.7    -850.06650    -849.91001    -849.88531   0.348E-01   15.64
>       82  0.02447   413.8    -850.06899    -849.90977    -849.88531   0.356E-01   15.72
>       83  0.02440   420.5    -850.07148    -849.90971    -849.88531   0.365E-01   15.68
>       84  0.02457   426.3    -850.07389    -849.90989    -849.88531   0.374E-01   15.66
>       85  0.02487   400.0    -850.07616    -849.92227    -849.89740   0.382E-01   15.67
>       86  0.02490   405.3    -850.07823    -849.92229    -849.89739   0.391E-01   15.58
>       87  0.02461   411.2    -850.08021    -849.92200    -849.89739   0.400E-01   15.67
>       88  0.02444   416.8    -850.08218    -849.92183    -849.89739   0.410E-01   15.63
>       89  0.02450   421.6    -850.08411    -849.92190    -849.89740   0.419E-01   15.69
>       90  0.02471   425.8    -850.08592    -849.92210    -849.89739   0.429E-01   15.65
>       91  0.02498   429.6    -850.08767    -849.92238    -849.89739   0.439E-01   15.68
>       92  0.02530   400.0    -850.08939    -849.93549    -849.91019   0.450E-01   15.68
>       93  0.02533   404.1    -850.09100    -849.93551    -849.91019   0.460E-01   15.63
>       94  0.02499   409.1    -850.09258    -849.93517    -849.91018   0.470E-01   15.67
>       95  0.02471   414.1    -850.09420    -849.93489    -849.91019   0.481E-01   15.65
>       96  0.02464   418.3    -850.09579    -849.93484    -849.91019   0.492E-01   15.69
>       97  0.02470   422.1    -850.09728    -849.93489    -849.91018   0.503E-01   15.66
>       98  0.02488   425.5    -850.09878    -849.93507    -849.91018   0.514E-01   15.70
>       99  0.02516   428.8    -850.10032    -849.93534    -849.91018   0.526E-01   15.68
>      100  0.02547   400.0    -850.10189    -849.94800    -849.92253   0.537E-01   15.65
>      101  0.02548   403.9    -850.10339    -849.94800    -849.92252   0.549E-01   15.69
>      102  0.02510   408.8    -850.10489    -849.94762    -849.92252   0.561E-01   15.64
>      103  0.02478   413.6    -850.10643    -849.94729    -849.92252   0.573E-01   15.76
>      104  0.02473   417.9    -850.10803    -849.94726    -849.92253   0.585E-01   15.58
>      105  0.02486   421.7    -850.10963    -849.94738    -849.92252   0.597E-01   15.60
>      106  0.02511   425.3    -850.11128    -849.94763    -849.92252   0.610E-01   15.70
>      107  0.02542   428.9    -850.11297    -849.94794    -849.92252   0.622E-01   15.53
>      108  0.02575   400.0    -850.11473    -849.96083    -849.93509   0.635E-01   15.66
>      109  0.02576   404.5    -850.11647    -849.96084    -849.93509   0.647E-01   15.70
>      110  0.02534   410.1    -850.11821    -849.96042    -849.93508   0.660E-01   15.64
>      111  0.02494   415.8    -850.11998    -849.96002    -849.93508   0.673E-01   15.61
>      112  0.02481   420.8    -850.12181    -849.95989    -849.93508   0.686E-01   15.61
>      113  0.02497   425.4    -850.12373    -849.96005    -849.93509   0.699E-01   15.63
>      114  0.02526   429.7    -850.12568    -849.96034    -849.93508   0.712E-01   15.67
>      115  0.02559   400.0    -850.12766    -849.97377    -849.94818   0.726E-01   15.68
>      116  0.02561   405.0    -850.12959    -849.97378    -849.94817   0.739E-01   15.67
>      117  0.02521   411.1    -850.13154    -849.97338    -849.94817   0.752E-01   15.65
>      118  0.02484   417.2    -850.13353    -849.97301    -849.94817   0.766E-01   15.74
>      119  0.02475   422.7    -850.13557    -849.97292    -849.94817   0.779E-01   15.62
>      120  0.02491   427.7    -850.13765    -849.97309    -849.94818   0.793E-01   15.68
>      121  0.02520   400.0    -850.13976    -849.98586    -849.96067   0.807E-01   15.67
>      122  0.02524   405.2    -850.14181    -849.98591    -849.96067   0.820E-01   15.69
>      123  0.02494   411.4    -850.14387    -849.98561    -849.96067   0.834E-01   15.63
>      124  0.02464   417.5    -850.14594    -849.98531    -849.96067   0.847E-01   15.64
>      125  0.02460   423.0    -850.14802    -849.98527    -849.96067   0.861E-01   15.67
>      126  0.02479   428.0    -850.15014    -849.98546    -849.96067   0.875E-01   15.67
>      127  0.02506   400.0    -850.15222    -849.99832    -849.97326   0.889E-01   15.65
>      128  0.02508   405.1    -850.15419    -849.99833    -849.97325   0.903E-01   15.67
>      129  0.02481   411.0    -850.15620    -849.99807    -849.97325   0.917E-01   15.60
>      130  0.02457   416.8    -850.15820    -849.99783    -849.97326   0.931E-01   15.58
>      131  0.02453   422.0    -850.16015    -849.99779    -849.97325   0.945E-01   15.70
>      132  0.02470   426.6    -850.16208    -849.99795    -849.97326   0.959E-01   15.68
>      133  0.02494   400.0    -850.16397    -850.01007    -849.98513   0.974E-01   15.65
>      134  0.02496   404.6    -850.16575    -850.01008    -849.98513   0.988E-01   15.64
>      135  0.02463   409.9    -850.16746    -850.00975    -849.98512   0.100E+00   15.59
>      136  0.02434   415.1    -850.16915    -850.00946    -849.98512   0.102E+00   15.66
>      137  0.02430   419.5    -850.17083    -850.00943    -849.98513   0.103E+00   15.58
>      138  0.02443   423.4    -850.17244    -850.00956    -849.98512   0.105E+00   15.63
>      139  0.02464   426.8    -850.17400    -850.00977    -849.98513   0.106E+00   15.65
>      140  0.02484   400.0    -850.17544    -850.02154    -849.99670   0.108E+00   15.59
>      141  0.02480   403.6    -850.17677    -850.02149    -849.99670   0.109E+00   15.58
>      142  0.02447   407.8    -850.17809    -850.02117    -849.99670   0.110E+00   15.61
>      143  0.02417   411.9    -850.17933    -850.02087    -849.99670   0.112E+00   15.59
>      144  0.02410   415.2    -850.18053    -850.02080    -849.99670   0.113E+00   15.59
>      145  0.02416   417.9    -850.18163    -850.02086    -849.99670   0.115E+00   15.62
>      146  0.02429   420.2    -850.18266    -850.02100    -849.99670   0.117E+00   15.64
>      147  0.02445   422.3    -850.18361    -850.02115    -849.99670   0.118E+00   15.67
>      148  0.02461   424.1    -850.18447    -850.02131    -849.99670   0.120E+00   15.62
>      149  0.02477   425.8    -850.18530    -850.02147    -849.99670   0.121E+00   15.66
>      150  0.02490   427.5    -850.18606    -850.02160    -849.99670   0.123E+00   15.66
>      151  0.02499   429.0    -850.18675    -850.02169    -849.99670   0.124E+00   15.65
>      152  0.02504   400.0    -850.18736    -850.03347    -850.00843   0.126E+00   15.64
>      153  0.02479   401.9    -850.18786    -850.03322    -850.00842   0.128E+00   15.68
>      154  0.02427   404.5    -850.18834    -850.03270    -850.00842   0.129E+00   15.60
>      155  0.02383   406.9    -850.18881    -850.03226    -850.00843   0.131E+00   15.67
>      156  0.02362   408.5    -850.18920    -850.03205    -850.00843   0.132E+00   15.65
>      157  0.02361   409.4    -850.18956    -850.03204    -850.00843   0.134E+00   15.59
>      158  0.02370   410.0    -850.18988    -850.03213    -850.00842   0.136E+00   15.57
>      159  0.02384   410.4    -850.19018    -850.03226    -850.00843   0.137E+00   15.69
>      160  0.02397   410.8    -850.19045    -850.03239    -850.00842   0.139E+00   15.63
>      161  0.02408   411.2    -850.19071    -850.03251    -850.00843   0.141E+00   15.63
>      162  0.02415   411.7    -850.19096    -850.03258    -850.00842   0.143E+00   15.62
>      163  0.02420   412.2    -850.19122    -850.03263    -850.00842   0.144E+00   15.67
>      164  0.02425   412.8    -850.19150    -850.03267    -850.00843   0.146E+00   15.66
>      165  0.02426   413.5    -850.19178    -850.03268    -850.00842   0.148E+00   15.70
>      166  0.02426   414.2    -850.19204    -850.03268    -850.00842   0.150E+00   15.64
>


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