[Pw_forum] 答复: Error in Turbo_lanczos.x to calculate the adsorption coefficiency

[Timrov Iurii]

Dear Clarence Leung,


> But I can find the input description of turbo_EELS .


The description of the input parameters for turboEELS is here: TDDFPT/Doc/INPUT_EELS.def


> What is the meaning of q ?


It is a transferred momentum. Have a look at these papers:


"Electron energy loss and inelastic x-ray scattering cross sections from time-dependent density-functional perturbation theory"
Authors: I. Timrov, N. Vast, R. Gebauer, and S. Baroni
Source: PHYSICAL REVIEW B   Volume: 88   Article Number: 064301   Published: AUG 2 2013
See also: PHYSICAL REVIEW B 91, 139901(E) (2015)

"turboEELS - A code for the simulation of the electron energy loss and inelastic X-ray scattering spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory"
Authors: I. Timrov, N. Vast, R. Gebauer, and S. Baroni
Source: Computer Physics Communications  Volume: 196  Article Number: 460 Published: 4 JUNE 2015


> How can we get (x y z) 3 Polarization direction ? use the command ipol = 4 ? like the turbo_lanczos?


No, "ipol" variable is not present in turboEELS.


As I wrote above, q is the transferred momentum, it is a vector. So depending on the direction of q you can get different behavior of the loss function -Im[1/eps] and Im[eps] (it depends also on the modulus of q). Have a look at this paper: I. Timrov et al., Phys. Rev. B 95, 094301 (2017).

HTH


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



________________________________
?件人: pw_forum-bounces at pwscf.org <pw_forum-bounces at pwscf.org> 代表 Timrov Iurii <iurii.timrov at epfl.ch>
?送??: 2017年3月6日 22:43:42
收件人: pw_forum at pwscf.org
主?: Re: [Pw_forum] Error in Turbo_lanczos.x to calculate the adsorption coefficiency


Dear Clarence,


When posting to pw_forum please do not forget to write your affiliation!


> As far as I know, the turboTDDFT is not extended to metals,


Yes, you are right.


> So we should use fixed occupation in the scf calculation, right?


Yes


> However, if I use fixed occupation in scf, the error is
> ' charge is wrong: smearing is needed  '. Because the system considered is odd electron.

Then you have to use smearing. I think there is no workaround with turboTDDFT for metals: one has to extend it to metals.

> What should I do to calculate the adsorption coefficiency of system with odd electrons.


aBsorption, not aDsorption


Probably you may try to use turboEELS, which is extended to metals. Namely, use very small q (but not exactly zero) and plot the imaginary part of the dielectric function.


HTH


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 LEUNG Clarence <liangxy123 at hotmail.com>
Sent: Monday, March 6, 2017 9:51 AM
To: pw_forum at pwscf.org
Subject: [Pw_forum] Error in Turbo_lanczos.x to calculate the adsorption coefficiency


Dear PWscf users,


As far as I know, the turboTDDFT is not extended to metals, So we should use fixed occupation in the scf calculation, right?


However, if I use fixed occupation in scf, the error is

' charge is wrong: smearing is needed  '. Because the system considered is odd electron.

What should I do to calculate the adsorption coefficiency of system with odd electrons.

Many thanks,

Clarence

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