[CP2K-user] [CP2K:17500] Re: Carbon Nitride cell optimization not converging

[Marcella Iannuzzi]

Dear Shreya

In none of the optimisation step the wave function optimisation has 
converged, therefore forces and stress tensor are absolutely unreliable. 
My suggestion is that you first find some good settings that allow the 
convergence of the single point calculation for the initial structure.

Regards
Marcella

On Tuesday, August 16, 2022 at 6:39:35 PM UTC+2 shrsi... at gmail.com wrote:

> Dear all,
> I am trying to optimize the crystal structure of carbon nitride  (Unit 
> cell contains 144 atoms: C48H24N72). I have tried various suggestions for 
> Basis sets (SZV, DZVP, TZVP), optimization method (CG BFGS, L-BFGS) but 
> cell-optimization is not converging. Energy is highly fluctuating, 
> ultimately forces on a set of atoms become very high and pressure deviation 
> huge. The initial structure is already optimized in FHI-AIMS, and taken 
> from a reference (
> https://pubs.acs.org/doi/full/10.1021/acs.chemmater.7b00965).
> Particularly, I noticed very high forces on Nitrogen atoms that are 
> involved in Hydrogen-bonding (see attached image of before and after 
> structure)
> I have attached one of the CP2K input file, initial geometry and output 
> file for your reference.
> Thanks in advance.
> Shreya
> Email: shrsi... at gmail.com
>
>

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