[QE-users] Atomic velocities units

[Lorenzo Paulatto]

I'm not sure, actually the time conversion I gave you is for pw.x, as cp.x use Hartree units instead of Rydberg for the energy there is a possible factor 2 difference (the base to find out this conversion is keep in mind that [ħ]=J·s=1 in atomic units.

The input manual says that pw.x velocities are just "atomic units", no conversion is done in the code as far as I could see.
Also keep in mind that ATOMIC_VELOCITIES is a seldom used feature, and may have bugs (i.e. I recently found out that it does not work with svr thermostat because of a little bug)
hth
--
Lorenzo Paulatto - Paris
On Jul 29 2021, at 8:17 pm, valeria arteaga muñiz <valitzelar at hotmail.com> wrote:
>
> Hello Lorenzo,
>
> Thanks for your reply. This is also for the pw.x code, right?
>
> Best,
> Valeria
>
> From: Lorenzo Paulatto (https://link.getmailspring.com/link/17A87165-F0AB-4C7C-9C86-AEE21336990C@getmailspring.com/0?redirect=mailto%3Apaulatz%40gmail.com&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D)
> Sent: Thursday, July 29, 2021 11:18 AM
> To: Quantum ESPRESSO users Forum (https://link.getmailspring.com/link/17A87165-F0AB-4C7C-9C86-AEE21336990C@getmailspring.com/1?redirect=mailto%3Ausers%40lists.quantum-espresso.org&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D)
> Cc: users at lists.quantum-espresso.org (https://link.getmailspring.com/link/17A87165-F0AB-4C7C-9C86-AEE21336990C@getmailspring.com/2?redirect=mailto%3Ausers%40lists.quantum-espresso.org&recipient=dXNlcnNAbGlzdHMucXVhbnR1bS1lc3ByZXNzby5vcmc%3D)
> Subject: Re: [QE-users] Atomic velocities units
>
>
>
>
> It depends on which units you have specified for atomic positions. Regarding time,
> 1 a.u.=4.8378 * 10^-17 s
>
>
>
> kind regards
>
>
> --
> Lorenzo Paulatto - Paris
>
>
> On Jul 29 2021, at 5:20 am, valeria arteaga muñiz <valitzelar at hotmail.com> wrote:
>
> > Hello everyone. I am trying to perform a MD run using the pw.x code. I'd like to use the atomic positions and also velocities from another run in Angstroms and Å/picoseconds to the QE input, but I am not sure about the units I need to use. In the documentation, there says it should be atomic units, and when I read the co.c documentation it was the same, but in the description they mentioned we needed to use the units as they're in the atomic positions card and time in a.u. does anyone have an idea of what convertion should I use?
> >
> > Thanks for your time
> >
> > _______________________________________________
> >
> > Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> >
> > users mailing list users at lists.quantum-espresso.org
> >
> > https://lists.quantum-espresso.org/mailman/listinfo/users
> >
>
>
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20210730/af5a9b9d/attachment.html>