Dear Prem Sen,

> I was trying in different way to converge scf calculation in case of carbon 
> dimer without "smearing". First I converge the system using "smearing" then 
> again I performed the scf calculation by changing the "restart_mode" from 
> "from_scratch" to "restart". In this condition, the scf calculation for 
> carbon dimer is converging & also turbo_davidson.x is possible. Do you think, 
> this is a right approach ??

I am not sure, but I would probably not rely on this approach. I think that if 
the system is gapped, then it should be possible to converge the ground state 
calculation without any intermediate calculation with a smearing.

> Also I have observed that if I am using hybrid functional, the system is 
> converging normally (keeping the restart_mode = from_scratch & without 
> "smearing").

This seems to indicate that with a hybrid functional you open a gap, and hence 
no smearing is needed in the calculation.

> Can I compute the absorption spectra for a molecule having triplet ground 
> state using turbo_davidson.x or turbo_lanczos.x ??


If this amounts to perform a spin-polarized calculation (and include 
magnetism), then these codes cannot be used because it is not implemented 
(currently only spin-unpolarized calculations can be performed with 
turbo_davidson.x and turbo_lanczos.x).


Regards,

Iurii


--
Dr. Iurii Timrov
Postdoctoral Researcher
Swiss Federal Institute of Technology Lausanne (EPFL)
Laboratory of Theory and Simulation of Materials (THEOS)
CH-1015 Lausanne, Switzerland

________________________________
From: [email protected] <[email protected]> on behalf of prem 
sen <[email protected]>
Sent: Tuesday, January 31, 2017 7:18 PM
To: [email protected]
Subject: [Pw_forum] Re : Learning TDDFT calculation in Atomic label (CH4 
molecule) using turbo_lanczos.x and turbo_davidson.x

Dear Dr. Iurii Timrov,
                            Thanks for the reply.
I was trying in different way to converge scf calculation in case of carbon 
dimer without "smearing". First I converge the system using "smearing" then 
again I performed the scf calculation by changing the "restart_mode" from 
"from_scratch" to "restart". In this condition, the scf calculation for carbon 
dimer is converging & also turbo_davidson.x is possible. Do you think, this is 
a right approach ??


Also I have observed that if I am using hybrid functional, the system is 
converging normally (keeping the restart_mode = from_scratch & without 
"smearing").


Can I compute the absorption spectra for a molecule having triplet ground state 
using turbo_davidson.x or turbo_lanczos.x ??











Thanks & regards,
Prem Sen
Ph.D. Student,
IIT Bombay,
Mumbai,India.
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