[QE-users] How to solve Error in routine C_bands Too many bands are not converged?

[Paolo Giannozzi]

You should first of all verify whether you have the same error with PBE. 
If so, there might be a problem in your structure; if not, it might be a 
problem with M06, which if I remember correctly is a meta-GGA 
functional. Meta-GGA functionals often produce numerical instabilities.

Paolo

On 1/30/23 08:00, AISWARYA CHANDRAN wrote:
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> __ __
> 
> I am doing the optimization of a system of 51 atoms containing two 
> dfferent types of atoms C and N using M06 functional.I used the ONCV 
> pseudo potential for both C_ONCV_PBE-1.0.UPF and  N_ONCV_PBE- 1.0  .UPF  
>   for C and N respectively.But I am getting an output with the error :
> *
> *
> *Error in routine C_bands*
> *Too many bands are not converged*
> *
> *
> *
> *
> I changed the pseudo potential for C and N as C_ONCV_PBE-1.2.UPF and  
> N_ONCV_PBE- 1.2.UPF  . Again it shows the same error
> *
> *
> *Error in routine C_bands*
> *Too many bands are not converged*
> *
> *
> What is the reason behind the problem.How can I solve this ?
> Thanks in advance
> 
> __ __
> 
> 
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222