On Mon, Oct 23, 2017 at 2:58 PM, Jalil Mahdizadeh <[email protected] > wrote:
> Thank you Axel. Hence, I'm thinking about ReaxFF based MD instead. What do > you think? > using reaxff to do what? axel. > ------------------------------------------ > S. J. Mahdizadeh > > On Oct 23, 2017 10:21 PM, "Axel Kohlmeyer" <[email protected]> wrote: > > > > On Mon, Oct 23, 2017 at 2:31 PM, Jalil Mahdizadeh < > [email protected]> wrote: > >> Thanks god. I was thinking I'm some kind of hollow man nobody can see >> me. However, dear axel recently a group of magicians accomplished such a >> "doomed project" successfully. >> > please note that you asked about "phase transition" without any > particular detail of what kind of transition you are after. in the most > general case one would assume a solid-liquid or liquid-gas transition. > those are activated processes with a significant barrier and all the issues > i mentioned. in fact, if somebody is after determining a melting point or > similar this way, even classical MD will fail. > > if you look at the transition in the paper you quote, it is a solid-solid > transition with rather minimal changes to the geometry and probably a very > small activation barrier, if any. yet, those folks still used a very large > supercell. that is quite telling. > > at any rate, my statement, that any temperature increase will be "rapid" > for AIMD simulations still stands. > > axel. > > > > >> PHYSICAL REVIEW B 96, 054111 (2017). >> ------------------------------------------ >> S. J. Mahdizadeh >> >> On Oct 23, 2017 9:16 PM, "Axel Kohlmeyer" <[email protected]> wrote: >> >>> >>> >>> On Mon, Oct 23, 2017 at 1:04 PM, Jalil Mahdizadeh < >>> [email protected]> wrote: >>> >>>> Dear QE users, >>>>> >>>>> I'm going to perform some vc-md with gradually heating/cooling process >>>>> until achieving phase transition temperature. Does any body know how to do >>>>> heating/cooling process in vc-md? I know that only "rescaling" option is >>>>> implemented for vc-md. Could Nobody help me? >>>>> >>>> >>> i suppose nobody has replied, because nobody wanted to tell you that >>> what you are asking about, is a doomed project. >>> >>> at the time scales accessible to DFT based MD simulation, >>> heating/cooling will *always* be rapid. >>> also, it is a good idea to stay away from phase transition >>> temperatures, since there you will have very bad sampling of phase space >>> and suffer from massive finite size effects. >>> >>> axel. >>> >>> >>> >>>> >>>>> Cheers. >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> -- >>>> S. J. Mahdizadeh >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> [email protected] >>>> http://pwscf.org/mailman/listinfo/pw_forum >>>> >>> >>> >>> >>> -- >>> Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 >>> College of Science & Technology, Temple University, Philadelphia PA, USA >>> International Centre for Theoretical Physics, Trieste. Italy. >>> >>> _______________________________________________ >>> 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 >> > > > > -- > Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 > College of Science & Technology, Temple University, Philadelphia PA, USA > International Centre for Theoretical Physics, Trieste. Italy. > > _______________________________________________ > 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 > -- Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 College of Science & Technology, Temple University, Philadelphia PA, USA International Centre for Theoretical Physics, Trieste. Italy.
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