[Pw_forum] Interaction energies between molecules

[Paolo Giannozzi]

If you can assume that only two-body interactions between the various
fragment pairs are relevant, what Stefano suggests is perfectly
appropriate. If you cannot or do not want to make such assumption,
you may choose a model and extract the parameters for your model
by fitting it to a few (or many) first-principle energies.

P.

On Sun, 2014-01-19 at 15:58 +0200, Manuel Fernandes wrote:
> Dear Stefano,
> 
> 
> Many thanks for your response. The issue is that I would like to know
> this answer when the molecules are within a crystal environment so
> that they are interacting with many neighbours and not just
> interacting with each other.
> 
> 
> Kind regards,
> 
> 
> Manuel
> 
> Date: Fri, 17 Jan 2014 15:39:49 +0100
> From: stefano de gironcoli <degironc at sissa.it>
> Subject: Re: [Pw_forum] Interaction energies between molecules
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <52D940B5.8080704 at sissa.it>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> the way to compute the interaction energy between two fragments is to
> compute the two fragments together and compare with the energy of the
> two separated fragments.
> 
> stefano
> 
> On 01/17/2014 10:32 AM, Manuel Fernandes wrote:
> > Hi everyone,
> >
> > Is there anyway to do a lattice energy calculation on an organic
> > crystal and then extract the interaction energy between pairs of
> > molecules of interest from that? What I would like to know for
> example
> > is how strongly a molecule as a whole interacts with its neighbours
> in
> > particular directions in a crystal environment.
> >
> > Thanking you in advance,
> >
> > Manuel Fernandes
> >
> >
> >
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-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222