1) Yes 2) Yes 3) Yes I attach to the mail my three inputs. Thank you, again, for your help.
Valentina Cantatore PostDoc Researcher @ Universit? del Piemonte Orientale 2014-09-18 11:26 GMT+02:00 Giovanni Cantele <giovanni.cantele at spin.cnr.it>: > > On 18 Sep 2014, at 10:40, Valentina Cantatore <valecantatore at gmail.com> > wrote: > > > Good morning to everyone. > > > > I would like to calculate the interaction energy between to molecules > using QE. What I set up was to fix the dimension of a cubic box at 20 A (I > think it is big enough to avoid interactions between the other replicated > molecules), calculate the energy of each of the two fragments (Ea and Eb) > and then calculate the energy of the two fragments together (Eab). What I > expect is that interaction energy (Ein) is given by Ein=Eab-(Ea+Eb). > > > > I also used the assume_isolated option for all calculations. I sampled > only gamma points. > > > > The results obtained are not of the same order of magnitude of those > obtained with a gaussian basis set on the same systems. > > > > Where am I wrong? Is it possible run this kind of calculation with > Quantum Espresso? Thank you > > > > Valentina Cantatore > > PostDoc Researcher @ Universit? del Piemonte Orientale > > > > > the procedure you describe is correct and this kind of calculations is of > course possible with QE. Just few questions: > 1) are you using the same XC approximation with gaussian and plane waves > runs (e.g. PBE)? > 2) are you sure that both calculations are converged with respect to the > respective parameters (in particular basis set size)? > 3) did you carefully check the energy units used by the two different > codes? > > Otherwise, you should provide more details and/or inputs to understand > what is going on. > > Giovanni > > -- > > Giovanni Cantele, PhD > CNR-SPIN > c/o Dipartimento di Fisica > Universita' di Napoli "Federico II" > Complesso Universitario M. S. Angelo - Ed. 6 > Via Cintia, I-80126, Napoli, Italy > e-mail: giovanni.cantele at spin.cnr.it > Phone: +39 081 676910 > Skype contact: giocan74 > > ResearcherID: http://www.researcherid.com/rid/A-1951-2009 > Web page: http://people.na.infn.it/~cantele > > > > _______________________________________________ > 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/20140918/c8d0b42d/attachment.html -------------- next part -------------- A non-text attachment was scrubbed... Name: MA_20.inp Type: application/octet-stream Size: 834 bytes Desc: not available Url : http://pwscf.org/pipermail/pw_forum/attachments/20140918/c8d0b42d/attachment.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: MAPbI2_20.inp Type: application/octet-stream Size: 1133 bytes Desc: not available Url : http://pwscf.org/pipermail/pw_forum/attachments/20140918/c8d0b42d/attachment-0001.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: PbI2_20.inp Type: application/octet-stream Size: 676 bytes Desc: not available Url : http://pwscf.org/pipermail/pw_forum/attachments/20140918/c8d0b42d/attachment-0002.obj
