Thank you for your precious tips. I will try with lammps that I'm a little expert on.
------------------------------------------ S. J. Mahdizadeh On Oct 23, 2017 11:00 PM, "Axel Kohlmeyer" <[email protected]> wrote: > > > On Mon, Oct 23, 2017 at 3:04 PM, Jalil Mahdizadeh < > [email protected]> wrote: > >> What we were discusting about (solid-solid phase transition probably). >> > > well, it depends on the specifics of the system, and whether reaxff is > applicable depends on whether there is a suitable and suitably reliable > parameter set. > nobody but yourself or somebody working on the same kind of problem can > make a definite statement. you'll have to carefully study the literature, > make tests and benchmarks and also study the thermodynamics of the > processes that you are modeling. none of that is specific to QE, either. > i've told you about as much as somebody with a general stat mech and MD > background can tell you. > > axel. > > > >> ------------------------------------------ >> S. J. Mahdizadeh >> >> On Oct 23, 2017 10:29 PM, "Axel Kohlmeyer" <[email protected]> wrote: >> >> >> >> 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. >> >> _______________________________________________ >> 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 >
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