[CPMD-list] the problem of MD simulation of H2O molecular
Axel Kohlmeyer
axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Wed Dec 8 14:56:57 CET 2004
On Wed, 8 Dec 2004, Nevil wrote:
hello nevil,
your time step is too large, so your CP-MD diverges after a while.
try using
TIMESTEP
3.0
or less. alternatively you can increase the fictitious electron
mass, but that may take you further away from the BO-surface
and give a larger 'dragging' effect.
btw: it has to be
TEMPCONTROL IONS
300.0 30.0
or so (i.e. 'TEMP' and not 'TEMO', and two numbers, the target
temperature and the delta for when to rescale the velocities.)
btw^2: you won't really need a cutoff of 120ry for those
pseudopotentials for MD. about 85ry should do about as well.
the 120ry was mainly needed to get nicer/smoother cubefiles.
regards,
axel.
N> Hi everyone:
N>
N> I download the input file of H2O molecular at this website:
N>
N> http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/cpmd-vmd/part5.html#chap7_sect1
N>
N> After the wavefuntion optimization, I wanted to continue the MD simulation of the H2O molecular. But I failed to get the result. The program seemed it couldn't converge.
N>
N> Is there anybody who have met this kind of problem? Please give me some advise.
N>
N> Thank you all very much. Good luck and happy new year. ^^
N>
N> The input file of MD simulation and the output are following:
N>
N> Input file:
N>
N> &CPMD
N> MOLECULAR DYNAMICS CP
N> RESTART WAVEFUNCTION COORDINATES LATEST
N> TRAJECTORY XYZ
N> MAXSTEP
N> 100
N> TIMESTEP
N> 4.0
N> TEMOCONTROL IONS
N> 300
N> ELECTROSTATIC POTENTIAL
N> RHOOUT
N> &END
N>
N> &DFT
N> FUNCTIONAL PBE
N> &END
N>
N> &SYSTEM
N> SYMMETRY
N> 0
N> CUTOFF
N> 120.0
N> ANGSTROM
N> CELL
N> 6.0 1.0 1.0 0.0 0.0 0.0
N> &END
N>
N> &ATOMS
N>
N> *O_MT_PBE KLEINMAN-BYLANDER
N> LMAX=P
N> 1
N> 2.904516 3.000000 2.926732
N>
N> *H_MT_PBE KLEINMAN-BYLANDER
N> LMAX=S
N> 2
N> 2.900437 3.000000 3.897528
N> 3.841176 3.000000 2.671532
N>
N> &END
N>
N> And the output file:
N>
N> NFI EKINC TEMPP EKS ECLASSIC EHAM DIS TCPU
N> 1 0.00000 0.0 -17.21135 -17.21135 -17.21135 0.108E-09 1.89
N> 2 0.00000 0.0 -17.21135 -17.21135 -17.21135 0.171E-08 1.87
N> 3 0.00000 0.1 -17.21135 -17.21135 -17.21135 0.857E-08 1.88
N> 4 0.00000 0.1 -17.21135 -17.21135 -17.21135 0.267E-07 1.88
N> 5 0.00000 0.2 -17.21135 -17.21135 -17.21135 0.643E-07 1.87
N> 6 0.00000 0.3 -17.21135 -17.21135 -17.21135 0.131E-06 1.88
N> 7 0.00000 0.3 -17.21136 -17.21135 -17.21135 0.240E-06 1.88
N> 8 0.00000 0.4 -17.21136 -17.21135 -17.21135 0.403E-06 1.88
N> 9 0.00000 0.5 -17.21136 -17.21135 -17.21135 0.635E-06 1.87
N> 10 0.00000 0.6 -17.21136 -17.21135 -17.21135 0.952E-06 1.88
N> 11 0.00000 0.8 -17.21136 -17.21135 -17.21135 0.137E-05 1.87
N> 12 0.00000 0.9 -17.21134 -17.21134 -17.21133 0.191E-05 1.88
N> 13 0.00002 1.0 -17.21127 -17.21127 -17.21125 0.260E-05 1.88
N> 14 0.00009 1.1 -17.21089 -17.21088 -17.21079 0.343E-05 1.88
N> 15 0.00050 1.2 -17.20877 -17.20876 -17.20826 0.447E-05 1.88
N> 16 0.00278 1.5 -17.19707 -17.19705 -17.19428 0.563E-05 1.88
N> 17 0.01544 1.4 -17.13222 -17.13221 -17.11676 0.719E-05 1.89
N> 18 0.08574 2.0 -16.77173 -16.77171 -16.68598 0.851E-05 1.90
N> 19 0.47317 0.8 -14.76271 -14.76270 -14.28953 0.112E-04 1.90
N> 20 2.51965 2.6 -3.39605 -3.39602 -0.87638 0.109E-04 1.90
N> 21 9.54015 77.3 68.11950 68.12023 77.66038 0.154E-04 1.91
N> 22 NaN NaN NaN NaN NaN 0.685E-05 403.49
N> 23 NaN NaN NaN NaN NaN NaN 410.48
N> 24 NaN NaN NaN NaN NaN NaN 410.67
N>
N>
--
=======================================================================
Dr. Axel Kohlmeyer e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53 Fax: ++49 (0)234/32-14045
D-44780 Bochum http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.
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