[CPMD-list] GEOMETRY OPTIMIZE

[Axel Kohlmeyer]

On Sun, 20 Apr 2008, morteza zare wrote:

MZ> Dear CPMD Community,

dear morteza,

MZ> I want to run the CPMD for ionic liquids to 
MZ> calculate transport properties.

hmmm... that is quite ambitious. 

MZ> Is the wavefunction optimization enough or I should 
MX> run a geometry optimization before MD.

unless you give us more specifics of how you prepared
your initial input, one can only give a very vague answer:

it depends.

a (partial) geometry optimization is usually only needed 
if your initial geometry has a very high potential energy,
e.g. due to some very close contacts. you should also keep
in mind, that if you continue the geometry optimization for
too long, you'll have to heat your system up again, i.e.
it may take even longer to equilibrate.

on top of that, you can easily figure out the answer by
yourself. just start the MD and see how well it goes. 
with the kind of cpu resource that you need for this kind 
of project anyways, it should not be a big problem. not
to mention that you need to do exploratory runs to figure
out the proper parameters for fictitious mass and time step.

cheers,
   axel.

MZ> 
MZ>   Thanks in advance
MZ> 
MZ> Morteza
MZ> 

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