[Octopus-users] Octopus-users Digest, Vol 77, Issue 5

Tue Jan 25 04:07:12 WET 2011

Dear Miguel,

 I think the link is:
http://www.google.com/books?hl=zh-TW&lr=&id=jRlWdiwViUYC&oi=fnd&pg=PA155&dq=%27ME+Casida+Time-dependent+density+functional+response+theory+for+molecules%22&ots=YjxXOy4vNr&sig=NjbFmDm_S_BORMWaGq59o-Ho4Po#v=onepage&q&f=false

I have another question: Does the Casida Linear Response implemented in octopus, like time-propagation, consider the temperature only in ground state calculation and don't change the occupation during the TDDFT process?

Thank you for your reply

Sincerely yours

Piin-Ruey Pan
Department of physics
National Taiwan University

> From: octopus-users-request at tddft.org
> Subject: Octopus-users Digest, Vol 77, Issue 5
> To: octopus-users at tddft.org
> Date: Mon, 24 Jan 2011 12:00:02 +0000
> 
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> Today's Topics:
> 
> 1. TDDFT at finite temperature (Pan Piin-Ruey)
> 2. Re: TDDFT at finite temperature (David Strubbe)
> 3. Re: TDDFT at finite temperature (Miguel Marques)
> 4. Re: using MGGA from libxc (Miguel Marques)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Mon, 24 Jan 2011 10:54:39 +0800
> From: Pan Piin-Ruey <iealtamperodicooti_s at hotmail.com>
> To: <octopus-users at tddft.org>
> Subject: [Octopus-users] TDDFT at finite temperature
> Message-ID: <COL105-W32193B1AC69FDF9F3790BFE1FD0 at phx.gbl>
> Content-Type: text/plain; charset="big5"
> 
> 
> Dear octopus users,
> I found that there is a variable in octopus that controls the electronic occupations (SmearingFunction = Fermi_dirac), and I want to learn more about it. 
> Can someone give me theoretical information about how octopus combines finite temperature and TDDFT?
> 
> P.S. I?m new to TDDFT; I have researched the topic using google for a while, but I couldn?t find the answer I want. 
> (The information I found are mostly about non-equilibrium Green function, but not Time-propagation or Linear response at finite temperature. )
> 
> Thanks a lot!
> 
> Sincerely yours
> 
> Piin-Ruey Pan
> Department of physics
> National Taiwan University
> 
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> ------------------------------
> 
> Message: 2
> Date: Sun, 23 Jan 2011 19:08:11 -0800
> From: David Strubbe <dstrubbe at berkeley.edu>
> To: Pan Piin-Ruey <iealtamperodicooti_s at hotmail.com>
> Cc: octopus-users at tddft.org
> Subject: Re: [Octopus-users] TDDFT at finite temperature
> Message-ID:
> <AANLkTimO-S08YY_o0mRn07bPzaQNGqq2EOMhccB_XJvu at mail.gmail.com>
> Content-Type: text/plain; charset=windows-1252
> 
> Piin-Ruey,
> 
> Regarding Sternheimer linear response with finite temperature: see
> Stefano de Gironcoli, Phys Rev B 51, 6773(R) (1995). This is static
> but Octopus implements the generalization to nonzero frequency.
> 
> For Casida linear response with finite temperature, see the original
> Casida paper: ME Casida, "Time-dependent density functional response
> theory for molecules," ?in Recent Advances in Density Functional
> Methods, edited by DE Chong, vol. 1 of Recent Advances in
> Computational Chemistry, pp. 155-192 (World Scientific, Singapore),
> available at http://dcm.ujf-grenoble.fr/PERSONNEL/CT/casida/research/chong.ps
> 
> David
> 
> 2011/1/23 Pan Piin-Ruey <iealtamperodicooti_s at hotmail.com>
> >
> > Dear?octopus?users,
> >
> > ?? I found that there is a variable in octopus that controls the electronic occupations (SmearingFunction = Fermi_dirac), and I want to learn more about it.
> >
> > Can someone give me theoretical information about how octopus combines finite temperature and TDDFT?
> >
> >
> >
> > P.S. I?m new to TDDFT; I have researched the topic using google for a while, but I couldn?t find the answer I want.
> >
> > (The information I found are mostly about non-equilibrium Green function, but not Time-propagation or Linear response at finite temperature. )
> >
> >
> >
> > Thanks a lot!
> >
> >
> >
> > Sincerely yours
> >
> >
> >
> > Piin-Ruey Pan
> >
> > Department of physics
> >
> > National Taiwan University
> >
> >
> >
> > _______________________________________________
> > Octopus-users mailing list
> > Octopus-users at tddft.org
> > http://www.tddft.org/mailman/listinfo/octopus-users
> >
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Mon, 24 Jan 2011 10:43:43 +0100
> From: Miguel Marques <marques at teor.fis.uc.pt>
> To: octopus-users at tddft.org
> Subject: Re: [Octopus-users] TDDFT at finite temperature
> Message-ID: <4D3D49CF.2050905 at teor.fis.uc.pt>
> Content-Type: text/plain; charset=windows-1252; format=flowed
> 
> Dear David, Piin-Ruey,
> 
> I think the situation is not so trivial. It is true that one can make 
> a quick and dirty generalization of the work of de Gironcoli, and that 
> is what is implemented in octopus. However, to my knowledge there is no 
> proper formulation of TDDFT with an electronic temperature. There are 
> two "schools":
> 
> 1) The electronic temperature should just be used to obtain the initial 
> state for TDDFT, and the propagation should not change the occupations. 
> This is what happens when you do time-propagation with octopus. It is 
> also the "correct" way according to Hardy Gross, etc. (I asked them so 
> years ago, that they may have changed opinion ;)) This amount, in my 
> opinion, to disconnect the system from the reservoir when one starts the 
> propagation. Note that this also leads to the incorrect static limit.
> 
> 2) In my opinion, the "correct" way is to keep the system connected to 
> the reservoir, i.e., the occupation numbers should change with time. 
> However, in this case, one does not know how to change them. One could 
> try an "adiabatic" procedure, i.e., calculating the expectation value of 
> the Hamiltonian, and use these time-dependent "eigenvalues" to adjust 
> the occupations. I think that what is implemented in the Sternheimer 
> approach in octopus amounts to this (correct me if I am wrong). This, 
> however, is not the whole story I think.
> 
> On the other hand, changing occupation numbers in TD open a pandora 
> box (see the recent work on TD density-matrix theory).
> 
> I would be very glad if someone has some more insight on this 
> problem, as it has been bugging me for several years now...
> 
> miguel
> 
> P.S. Davis, the link you sent is no longer valid, so I could not check 
> the paper ;((
> 
> On 01/24/2011 04:08 AM, David Strubbe wrote:
> > Piin-Ruey,
> >
> > Regarding Sternheimer linear response with finite temperature: see
> > Stefano de Gironcoli, Phys Rev B 51, 6773(R) (1995). This is static
> > but Octopus implements the generalization to nonzero frequency.
> >
> > For Casida linear response with finite temperature, see the original
> > Casida paper: ME Casida, "Time-dependent density functional response
> > theory for molecules," in Recent Advances in Density Functional
> > Methods, edited by DE Chong, vol. 1 of Recent Advances in
> > Computational Chemistry, pp. 155-192 (World Scientific, Singapore),
> > available at http://dcm.ujf-grenoble.fr/PERSONNEL/CT/casida/research/chong.ps
> >
> > David
> >
> > 2011/1/23 Pan Piin-Ruey<iealtamperodicooti_s at hotmail.com>
> >> Dear octopus users,
> >>
> >> I found that there is a variable in octopus that controls the electronic occupations (SmearingFunction = Fermi_dirac), and I want to learn more about it.
> >>
> >> Can someone give me theoretical information about how octopus combines finite temperature and TDDFT?
> >>
> >>
> >>
> >> P.S. I?m new to TDDFT; I have researched the topic using google for a while, but I couldn?t find the answer I want.
> >>
> >> (The information I found are mostly about non-equilibrium Green function, but not Time-propagation or Linear response at finite temperature. )
> >>
> >>
> >>
> >> Thanks a lot!
> >>
> >>
> >>
> >> Sincerely yours
> >>
> >>
> >>
> >> Piin-Ruey Pan
> >>
> >> Department of physics
> >>
> >> National Taiwan University
> >>
> >>
> >>
> >> _______________________________________________
> >> Octopus-users mailing list
> >> Octopus-users at tddft.org
> >> http://www.tddft.org/mailman/listinfo/octopus-users
> >>
> > _______________________________________________
> > Octopus-users mailing list
> > Octopus-users at tddft.org
> > http://www.tddft.org/mailman/listinfo/octopus-users
> >
> 
> 
> -- 
> Dr. Miguel A. L. Marques
> marques at tddft.org
> http://www.tddft.org/bmg
> 
> Laboratoire de Physique de la Mati?re Condens?e et Nanostructures
> (LPMCN) - Universit? Lyon I
> B?timent Brillouin, Domaine scientifique de la DOUA
> 69622 Villeurbanne Cedex
> Tel +33 (0)4 72448187
> Fax +33 (0)4 72432648
> 
> 
> 
> ------------------------------
> 
> Message: 4
> Date: Mon, 24 Jan 2011 10:50:52 +0100
> From: Miguel Marques <marques at teor.fis.uc.pt>
> To: octopus-users at tddft.org
> Subject: Re: [Octopus-users] using MGGA from libxc
> Message-ID: <4D3D4B7C.4050603 at teor.fis.uc.pt>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Dear Vladimir,
> 
> Meta-GGAs are not standard density-functionals. In fact, although by 
> virtue of the Hohenberg-Kohn theorem tau is a functional of the density 
> n, it is an implicit density functional and not an explicit one (several 
> approximations to \tau[n] do exist though). In view of this, there are 
> two ways of implementing a meta-GGA in a DFT code:
> 
> 1) the "correct" DFT way, i.e., treat a meta-GGA as a _orbital_ 
> functional and use the machinery of the optimized effective potential 
> (OEP) to construct the potential.
> 
> 2) To approximate the xc potential in DFT by 1/psi \delta E_xc / \delta 
> psi^* (from memory, but it should be something like that). This is the 
> pragmatic approach used in all quantum-chemistry codes, but it goes away 
> from "pure" DFT.
> 
> So, the answer to your question, libxc can not provide \delta tau / 
> \delta \rho as this derivative can not be so easily obtained, but that 
> derivative is not needed to obtain the potential...
> 
> hope this helped,
> miguel
> 
> On 01/22/2011 01:37 PM, Vladimir Nazarov wrote:
> > Hello All,
> >
> > I have a (probably naive) question about libxc library:
> >
> > I want to know the xc potential within MGGA.
> > For this, I call xc_mgga_vxc. But how to construct v_xc(r) from the 
> > output of
> > xc_mgga_vxc: We evidently need \delta tau / \delta \rho, which is not 
> > among the output parameters of xc_mgga_vxc ?
> > (\tau is the kinetic energy density, and \rho is the density).
> >
> > Thank you very much in advance.
> > Vladimir Nazarov.
> > _______________________________________________
> > Octopus-users mailing list
> > Octopus-users at tddft.org
> > http://www.tddft.org/mailman/listinfo/octopus-users
> >
> 
> 
> -- 
> Dr. Miguel A. L. Marques
> marques at tddft.org
> http://www.tddft.org/bmg
> 
> Laboratoire de Physique de la Mati?re Condens?e et Nanostructures
> (LPMCN) - Universit? Lyon I
> B?timent Brillouin, Domaine scientifique de la DOUA
> 69622 Villeurbanne Cedex
> Tel +33 (0)4 72448187
> Fax +33 (0)4 72432648
> 
> 
> 
> ------------------------------
> 
> _______________________________________________
> Octopus-users mailing list
> Octopus-users at tddft.org
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> 
> 
> End of Octopus-users Digest, Vol 77, Issue 5
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