[CPMD-list] negative temperatures
Ari P Seitsonen
ari.p.seitsonen at iki.fi
Wed Nov 2 20:22:13 CET 2005
Dear Julen,
No, the temperature does not become negative: The problem is that the
fictitious electron temperature grows suddenly so much that the first
and second column in the ENERGIES file merge, and thus the third column,
which should be the temperature, is "shifted" to the fourth column. So
the question is, why does your fictitious kinetic energy explode. First
of all, the initial Kohn-Sham energy is POSITIVE, this means that either
the initial electronic or ionic structure is completely off. I would try
with
&CPMD
OPTIMIZE GEOMETRY
LBFGS
CONVERGENCE
5.D-5 0.01
&END
or similar, then starting the MD. Where did you get the initial
coordinates? If they are reasonable there is no need to perform any
geometry optimisation, and an 'OPTIMISE WAVEFUNCTION' would be a better
choice. And above all, if you perform geometry optimisation there is _NO_
temperature involved (unless you do SIMULATED ANNEALING, but if you use
'OPTIMIZE GEOMETRY' the TEMPERATURE does not make sense and is not
included).
As for the MD, was this a continuation run? Otherwise the options
RESTART DENSITY ACCUMULATORS VELOCITIES
do not make sense.
For the EMASS I would try a larger value (700 amu).
Greetings,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
CNRS & IMPMC, Université Pierre et Marie Curie
4 place Jussieu, case 115 / F-75252 Paris
Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820
On Wed, 2 Nov 2005, scklacoj at ikasle.ehu.es wrote:
> Dear CPMD users
>
> I'm trying to make a basic CPMD simulation with 32 water molecules.
> First of all I made a geometry optimization in 300 K, and after having
> ran it successfully I started the MD calculation.
> After the first time step we see that although I'm using the
> thermostat in 300 K with +- 50K, the temperature lows down to 50 K in
> the first step and suddenly switches to NEGATIVE TEMPERATURES, as we can
> see in the ENERGIES's head. Anyway I think that the ENERGIES doesn't
> look very well in general.
> I attach the input files and interesting parts of the outputs.
>
> Could someone advise me something?
>
> ******************************************************************************************************
> &CPMD
> OPTIMIZE GEOMETRY
> TEMPERATURE
> 300
> MAXSTEP
> 200
> TASKGROUPS
> 1
> TRAJECTORY XYZ
> TIMESTEP
> 25
> CONVERGENCE
> 5.D-5 1
> &END
>
...
>
>
> #### and the MD...
>
> ***********************************************************************************************
> &CPMD
> MOLECULAR DYNAMICS
> RESTART WAVEFUNCTION COORDINATES DENSITY LATEST ACCUMULATORS VELOCITIES
> TEMPCONTROL IONS
> 300.0 50.
> MAXSTEP
> 100
> TRAJECTORY SAMPLE
> 5
> TRAJECTORY XYZ
> MOVIE
> TASKGROUPS
> 1
> TIMESTEP
> 5
> EMASS
> 400.
> RESTFILE
> 2
> STORE
> 250
> CONVERGENCE
> 5.D-5 1
> TASKGROUPS
> 1
> &END
>
> &SYSTEM
> ANGSTROM
> SYMMETRY
> 1
> CELL
> 9.8652 1.0 1.0 0 0 0
> CUTOFF
> 25.0
> &END
>
> &ATOMS
> ISOTOPE
> 2.0
> 16.0
>
> *001-H-gpbe--bm.uspp VANDERBILT BINARY
> LMAX=S
> 64
> -3.3053 4.9253 1.6462
> -4.1572 5.0367 .3308
> 1.3023 2.9515 .4671
> 1.3089 4.0412 -.5595
> -3.3246 1.4120 3.6912
> -2.3056 1.9815 4.5961
> -2.0153 -2.1506 -5.7379
> -1.7446 -2.5453 -4.2040
> 3.5213 .3283 .5200
> 3.5479 -1.0061 -.1196
> 1.9785 -3.3683 -.2189
> 2.6026 -3.4973 -1.5429
> -2.9083 -5.6270 -1.6287
> -2.3040 -4.0368 -1.8099
> -.7906 2.8124 -3.9443
> -2.0663 2.3097 -3.1101
> 3.3302 2.6929 2.9588
> 4.6699 3.2498 2.0637
> 4.4492 .8866 3.0012
> 4.6789 -.7875 3.0252
> -.4812 -.6333 -2.9947
> -.3300 .9237 -3.1648
> -.9719 1.1798 .9333
> -1.9641 1.9451 1.8694
> 3.2151 -1.2830 -3.1774
> 1.7995 -.8313 -3.3422
> -2.7785 2.0950 -.6601
> -4.0498 2.1615 -1.5998
> -1.7959 -1.5878 1.8086
> -.2143 -1.4974 2.4894
> .6173 4.7556 -4.1965
> 1.2992 3.3833 -3.5257
> 5.1090 -4.3752 -2.0184
> 4.0067 -4.0474 -3.0793
> -3.3759 -.8193 -3.8202
> -4.5800 -.1709 -4.6131
> -3.6115 3.0902 -5.2556
> -3.7100 4.0840 -3.8886
> 4.0638 2.6215 -4.2526
> 2.3615 -4.4493 1.4573
> 2.7215 -2.8733 1.8612
> 2.2057 -.2147 2.3564
> 1.7463 -.2329 3.9005
> 3.7257 -5.2222 -4.7395
> 3.7753 -3.9425 -5.6148
> 4.6995 -2.4074 -1.5929
> 4.9959 -.9932 -2.1322
> -3.9829 -3.2018 3.9320
> -4.6345 -3.3871 2.4332
> 1.5482 -3.3035 4.7969
> .3599 -3.5032 3.7960
> 1.0989 1.8109 3.0071
> .6221 2.8214 4.0951
> -1.0159 -3.7951 1.8758
> -.5417 -5.3121 2.0707
> -1.5334 -2.0499 -1.1914
> -.3161 -2.8736 -1.7149
> 1.4561 .4856 .1831
> .4231 .6630 -1.0047
> -3.4878 -1.3011 .0322
> -2.3958 -.2550 .4789
> 3.9915 2.3055 -.5737
> 3.3432 2.2101 -2.1223
>
> *008-O-gpbe--bm.uspp VANDERBILT BINARY
> LMAX=P
> 32
> -4.2273 4.7694 1.2896
> 1.8911 3.7309 .1824
> -2.6627 2.1691 3.6881
> -2.4398 -2.2814 -4.8503
> 3.1003 -.5624 .6982
> 1.7078 -3.3004 -1.1622
> -3.1294 -4.6547 -1.6825
> -1.4391 1.9607 -3.8388
> 4.0215 2.4550 2.3137
> 4.8772 .0647 3.4458
> .1438 .1346 -2.7021
> -1.9325 1.4256 .9820
> 2.6318 -.9894 -3.8878
> -3.1172 2.5013 -1.4936
> -1.1560 -1.8513 2.5314
> .4868 3.8107 -3.8207
> 4.1354 -4.0452 -2.0990
> -4.2366 -.3320 -3.6654
> -4.2232 3.5631 -4.5819
> 3.0670 2.4224 -4.1612
> 2.0373 -3.5138 1.5742
> 1.4018 -.2406 2.9857
> 3.2679 -4.3570 -4.8315
> 4.8138 -1.4740 -1.2050
> -4.8116 -3.0132 3.3633
> .5384 -3.4208 4.7951
> .7478 2.7843 3.0293
> -1.3109 -4.7419 1.8237
> -1.2870 -2.6574 -1.9320
> .5992 .9986 -.0668
> -2.5128 -1.2389 .2823
> 4.0567 1.8381 -1.4912
>
> &END
>
> &DFT
> NEWCODE
> FUNCTIONAL PBE
> &END
> **************************************************************************************************
>
>
> ####This is the "head" of the ENERGIES in our cluster:
>
>
> ***********************************************************************
> 2 38.68933282 300.000 301.2239397190 301.3593122386 340.0486450588 0.225299E+04 23.16
> 3254.12215691 300.000 55.2871540330 55.4225265525 309.5446834671 0.225325E+04 23.31
> 4421.18460560 300.000 -117.4876672846 -117.3522947651 303.8323108341 0.225336E+04 23.29
> 5493.63432617 300.000 -186.7204456221 -186.5850731026 307.0492530679 0.225341E+04 22.95
> 6526.19284427 300.000 -220.3315112213 -220.1961387018 305.9967055701 0.225343E+04 22.67
> 7534.66862225 300.000 -226.9065438037 -226.7711712842 307.8974509656 0.225345E+04 22.65
> 8529.26193237 300.000 -221.5039893084 -221.3686167889 307.8933155842 0.225346E+04 22.77
> ******************************************************************************************************
>
> #### ...and the MD simulations seems to have finished correctly
> according to the output...
> __________________________________________________________________
> ****************************************************************
> * *
> * TIMING *
> * *
> ****************************************************************
> SUBROUTINE CALLS CPU TIME ELAPSED TIME
> NEWD 101 762.86 780.68
> RHOV 101 625.93 641.46
> S_INVFFT 12928 143.70 147.23
> FFT-G/S 38784 118.03 121.02
> RNLSM2 101 112.58 114.87
> NLFORCE 101 94.79 96.84
> RNLSM1 202 67.26 68.60
> RHOOFR 101 60.42 61.77
> ROTATE 607 57.24 58.49
> S_FWFFT 6464 54.62 56.05
> VPSI 101 51.30 52.58
> HNLMAT 101 45.06 45.86
> EICALC 101 40.72 41.47
> OVLAP 304 21.21 21.68
> QINIT 1 20.21 20.69
> RNLFL 101 16.23 16.64
> FWFFT 606 12.50 12.78
> GCENER 101 10.33 10.54
> INVFFT 505 10.23 10.50
> ----------------------------------------------------------------
> TOTAL TIME 2325.22 2379.76
> ****************************************************************
>
> CPU TIME : 0 HOURS 39 MINUTES 36.81 SECONDS
> ELAPSED TIME : 0 HOURS 40 MINUTES 33.33 SECONDS
>
> PROGRAM CPMD ENDED AT: Thu Oct 6 18:44:29 2005
> =============================================================
>
>
> Thanks very much
>
>
> --
> *************************************
> Julen Larrucea
> Kimika Fakultatea
> Euskal Herriko Unibertsitatea
> P.K.1072
> 20080 Donostia; Euskadi (Spain)
>
> Voice : +34-943-015341
> Fax : +34-943-015270
> E-mail: scklacoj at ikasle.ehu.es
> http://www.sc.ehu.es/chemistry/theory
> **************************************
>
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