[Pw_forum] about PW calculation of molecules

[Lorenzo Paulatto]

On Tue, 09 Feb 2010 08:33:33 +0100, patriot pershing <science35 at gmail.com>  
wrote:
> i have using espresso code to calculate the electronic structure and
> properties of COHmolecule and to do this work i have choose the free
> lattice

Dear patriot,
when you specify ibrav=0 (free axis) you also have to specify the axis...  
which was your choice?

> with alat of 100 au (bohr) and i have positionned the atoms in
> the center of lattice and when i have run the pw calculations this
> don't work.

I would be surprised if it did, it's a good idea to leave some empty space  
between periodic copies of the molecule, but 100 bohr is HUGE, probably  
you've just run out of memory. Anyway, what do you mean be "it does not  
work" precisely? Please remember to always supply as much information as  
possible when asking for help, this way you will get the best help in the  
shortest time.

> in the same topics iw ould ask if it is possible with espresso to
> determinate the binding energy between different molecules in ternairy
>  molecules (3 atoms per molecule)

Yes, you have to compute the energy of each component separately, then  
compare the sum with the energy of the components together.

best regards


-- 
Lorenzo Paulatto

*** Note: my affiliation has changed! please send future
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previously:
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