The procedure is the same... Interaction energy is the difference between the energy of the full system and the sum of the energies of its components. It is in general a manybody quantity.. If you ASSUME that it derives from a two body potential (with a given angular and radial dependence) you can estimate this function from a series of calculations in different configurations. This is just an approximation, though.
stefano (sent from my phone) > On 19 Jan 2014, at 14:58, Manuel Fernandes <0occam at gmail.com> 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 > > > > > > > > ______________________________ > _________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://pwscf.org/mailman/listinfo/pw_forum > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140119/8e1d1e6d/attachment.html
