[Pw_forum] Re : Learning TDDFT calculation in Atomic label (CH4 molecule) using turbo_lanczos.x and turbo_davidson.x

[Timrov Iurii]

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: pw_forum-bounces at pwscf.org <pw_forum-bounces at pwscf.org> on behalf of prem sen <premsen1502 at gmail.com>
Sent: Tuesday, January 31, 2017 7:18 PM
To: pw_forum at pwscf.org
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.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20170201/2c8ff257/attachment.html>