[CPMD-list] ionic liquid

[Axel Kohlmeyer]

On Sun, 13 Nov 2005, Younes Ansari wrote:

YA> Dear cpmd-list:
YA> I have send my questions in a document file.

hi,

please be aware of the fact, that sending word
documents as email will reduce the chances to
get a response significantly. 

two comments about your calculation:
i would be careful to call a system with 4 molecules
and 4 ions a liquid. you will suffer severe finite
size effects.

you are using goedecker pseudopotentials with a 
plane wave cutoff of 5ry, i.e. a _very_ incomplete
basis. no wonder your structure gets messed up.
you have to increase the cutoff to a much larger
number. i don't know these particular potentials,
but a cutoff requirement of 90-120ry is typical,
in certain cases even more.

as a simple test, you can do a single point calculation
with PRINT FORCES ON and the value of the forces
should change by less than 1.e-03 on increasing
the cutoff further.

axel.

YA> 
YA> 
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-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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