[QE-users] relax calculation on MD snapshots

[Chirantan Pramanik]

The input and output files are attached. I need a physical explanation of why the atomic coordinates do not converge from an MD simulation snapshot. The output shows the accuracy varies periodically but never reaches the target accuracy. This one is with cg diagonalization which is still running.

Regards,
Chirantan
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
Sent: Sunday, February 23, 2025 4:57 PM
To: users at lists.quantum-espresso.org <users at lists.quantum-espresso.org>
Subject: Re: [QE-users] relax calculation on MD snapshots

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Dear Chirantan
As detailed in thousands of previous posts, it is totally useless to
say "it does not converge" without providing all the details (input,
output, QE version, pseudopotentials,...)
HTH
Giuseppe

Quoting Chirantan Pramanik <chirantan.pramanik at weizmann.ac.il>:

> Hello,
>
> I need to calculate phonon for some structures of Mg in water
> obtained from MD simulations. I ran AIMD at 300K and performed 16000
> steps with 1 fs time step. Then, I collected equidistant snapshots
> from the temperature-stabilized region to compute phonon. However,
> according to a few previous studies, they optimized all atomic
> coordinates of the MD snapshots to get the reliable phonon required
> for isotopic study. When I try to optimize, the structures never
> converge. I tried using more steps and lower thresholds. But does
> not work. Please help to solve this. Also, as the Mg ion resides in
> the same water cage at this time, should most of the snapshots give
> the same optimized structure?
>
> Regards,
> Chirantan
>
>
>
>
> Chirantan Pramanik
> Postdoctoral Researcher
> Dept. of Earth and Planetary Sciences
> Weizmann Institute of Science
> Rehovot, Israel



GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>

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