[Pw_forum] molecular dynamics for metallic system

[Nicola Marzari]

If your system is a true metal, it will be tough to have a meaningful
dynamics with CP. You need to use PWSCF B-O simulations, and/or start
experimenting with CP in ensemble-dft mode.

If the system has a few states around the Fermi energy, and run in CP
mode would show a mild but steady increase of the fictitious electronic
kinetic energy, then you might succeed, by applying a thermostat on
electrons and one on ions.

In all these cases, you need experience, a lot of testing in small 
systems to get a feeling of things, etc... . It would be safe to start 
with reference calculations using PWSCF B-O.

					nicola


Mansoureh Pashangpour wrote:
> Dear All
> I am a PhD. student.I am interested in molecular dynamics for metallic 
> systems with external
> pressure,but at first I began  learning Car-Parrinello  molecular 
> dynamics and then I used it
> for my system with small dt (I am sending its plots for you).Do using 
> CP  with small dtinstead
> of BO for metallic systems  obtain correct result or not?
> How can I find the best dt ,emass.emass_cutoff for my system in BOMD and 
> CPMD()?
> I want to find affect of external pressure on ions in my system and I 
> must consider  many ions
> in a big cell.can I use a smaller cell with fewer ions to find dt 
> ,emass,...?
> I look forward to hearing from you as soon as possible.
> Thanks,
> Mansoureh

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Prof Nicola Marzari   Department of Materials Science and Engineering
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