[CPMD-list] Density Cubefile

[Axel Kohlmeyer]

>>> "BS" == Balasubramanian Sundaram <Dr.> writes:

hi bala,
[...]

BS> We found RHOOUT (through cpmd.x itself) to be easier to use than
BS> cpmd2cube,
BS> as we can avoid using the HALFMESH (I suppose cpmd2cube cumpulsorily
BS> writes
BS> the density in the HALFMESH). 

well, this is one of the things that got fixed. you may
be able to temporarily work around it by manually setting
the MESH parameter in the &SYSTEM section manually to 
twice the values that get automatically chosen.

BS> For the records: We use v3.7.2 on an IBM-SP-SMP.

BS> We do obtain the coordinates of the grid points in the way you describe.
BS> Our
BS> simulation cell is cubic.  So, the grid goes from 0 to L in each of the 
BS> 3 directions. However, the ion coordinates, after performing a PBC on
BS> the 
BS> molecular centre of mass, lie between -L/2 to +L/2. How does one
BS> position 
BS> the density grid on top of the ion positons?

please try to edit the file proppt.F, search for the string 
'PLOT WAVEFUNCTION' and then explicitely initialize the
array 'cubecenter' to zero. this might do the trick.
with the new cpmd version you will be able to set the 
center of the cubefile explicitely. for the time being
you have to use cpmd2cube for that.

BS> Specifically I am trying to reproduce the result of Laasonen, Sprik
BS> and
BS> Parrinello, JCP (1993) to obtain the molecular dipole moment of water
BS> molecules
BS> in liquid water, as a learning exercise. I realize that it is possible
>> 
>> if i am not totally mistaken, this has also been implemented in the
>> development version of cpmd. so you will have a nice opportunity to
>> cross-check your results.

BS> sorry, what feature has also been implemented in the development
BS> version?

calculation of dipole moments in real space.

BS> Thanks again for the help,

take care,
     axel.

BS> Regards,
BS> Bala






>> take care,
>> axel.
BS> to
BS> get this information from the Wannier+Ion centers as well, but I need to
BS> obtain
BS> it from the charge density+Ion Centers.
>> 
BS> Thanks!
>> 
BS> Best Regards,
BS> Bala
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>> 
>> --
>> 
>> =======================================================================
>> 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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--

=======================================================================
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.