Dear Paolo, Thank you very much for your prompt answer.
Best regards ======================== Dr. Daniel Reta, Post-doctoral Research Associate, Computational Chemistry, School of Chemistry University of Manchester Email: [email protected] ======================== ________________________________________ From: [email protected] [[email protected]] on behalf of Paolo Giannozzi [[email protected]] Sent: 13 April 2017 09:31 To: PWSCF Forum Subject: Re: [Pw_forum] Absolute energy dependent on ATOMIC_POSITION specification On Thu, Apr 13, 2017 at 10:20 AM, Daniel Reta <[email protected]> wrote: > I have run the same calculation specifying the atomic position with "crystal" > and with "angstrom", and I got two different absolute energies. Is this > correct? make a "diff" of the two outputs and you will find that they are not "the same calculation" > Also, the system is a molecular crystal with some ligands coordinated to > Ytrium. I find that I have to go to very high values of ecutwfc to converge > the absolute energy. I'm talking about 100 or 110 Ry approximately. Is this a > known feature? the convergence of absolute energies may be very slow, depending upon the pseudopotentials used. Energy differences between different structures of the same material typically converge much better. This is a known feature, yes. > Does working with such high values of ecutwfc introduce some biases in the > calculations? no, it just requires a big computer and a lot of time Paolo > Best regards > > > ======================== > > Dr. Daniel Reta, > Post-doctoral Research Associate, > Computational Chemistry, School of Chemistry > University of Manchester > > Email: [email protected] > > ======================== > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
