[Pw_forum] Strange values of Tc

[Giovanni Cantele]

I’m not an expert about el-ph calculations. However, if it were a calculation made by myself,
I would never trust Tc values obtained after modifying by hand lambda.f90, even if they were perfectly reasonable.

el-ph calculations for sure require extremely  well converged electron calculations as well as well extremely well converged phonon
calculations. So I would go through the phonon calculation, understand why there are negative frequencies and,
even once you have obtained all positive frequencies, understand whether or not they are converged.

Giovanni


> On 28 Jul 2017, at 13:26, Isaiah Moses <imoses87 at gmail.com> wrote:
> 
> Thanks a lot, Dr Giovanni.
> I appreciate your response.
> We observed few values of frequencies to be negative.
> Matdyn1 has few more with others having either the first or the first 2/3 to be negative.
> We set those to be zero, modifying lambda.f90 code.
> 
> Could that be the problem?
> 
> I've attached the input/output for lambda.x execution. Also matdyn1.
> 
> There are 62-points and 33 irreps.
> I appreciate your time.
> 
> -- 
> Isaiah Abu Moses
> Graduate Student,
> Physics Department,
> University of Ibadan,
> Nigeria
> <CyanoPh_lambda.in><CyanoPh_lambda.out><matdyn1>_______________________________________________
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-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.fisica.unina.it/~cantele

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