[Pw_forum] plot_2d in bands.x
Hi there, I'm trying to use the option plot_2d=.true. from bands.x. 1) How should I set up the preceding pw.x calculation? Just a "normal" scf with a large k-point grid on automatic is ok? Or it has to be calculation="bands"? 2) Whenever I try to run it, I receive the error *** namelist no longer valid: please use instead ***. I'm using espresso 5.0.3, and I am sure that I am using instead of , and I am ending it with a /: prefix='my-prefix' outdir='tmp3' filband='bands-' plot_2d=.true. / Recently another user named Ning Shen posted here on the forum with the same problem. What could be happening? Thanks, Prof. Leonardo Jorge Nanomol Group IF - USP - Brazil -- next part -- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20131209/d941d7f5/attachment.html
[Pw_forum] ecutvcut in Hybrid functionals
HSE is "a PBE0 with a cutoff". I don't know if it has been fixed, but some time ago ecutvcut interfered with that cutoff, making HSE behave just as PBE0 (i.e., when ecutvcut was on, calculations done with HSE and PBE0 gave the same results). Maybe that's why in the examples with HSE was used ecutvcut=0.0. I just don't know if this is still happening, or if the bug was fixed and just the example that wasn't updated. Leonardo Jorge PhD Student at USP - Brazil Nanomol Group http://nanomol.if.usp.br On Tue, Nov 20, 2012 at 10:48 AM, Jianpeng Liu wrote: > Hi Layla, > > Your comments are really really helpful! Thanks a lot! > > best, > Jianpeng > > > Dear Jianpeng, ecutvcut is a parameter which is not strictly bonded to > > hybrid functional parameters, but to strongly anisotropic supercells like > > in the case of quasi 1D systems and fock like operators. I will be more > > precise. If you have an hybrid functional AND you want to have the > > electronic properties of a polymer chain or a nanotube, i.e. if you > > multiply the cell parameter by the number of kpoint in each direction > then > > you obtain an effective supercell which is anisotropic (like 6*6*50), > then > > to avoid divergencies for small q vectors in the integration of the fock > > operator, one has to turn on exxdiv_treatment="vcut_ws" and ecutvcut=1.2 > > or > > something appropriate (you need to converge with this value). vcut_ws > > applies a real space cutoff in the wigner Seitz cell of your supercell > > until a reciprocal space cutoff of ecutvcut. The more is your cell > > anisotropic bigger has to be ecutvcut. If you are dealing with bulk > > materials, you do not have to care about this!!! > > > > hope it helps cheers > > > > Layla > > > > 2012/11/19 Jianpeng Liu > > > >> Dear QE users and developers, > >> > >> I am doing hybrid-functional calculations, and I am confused about the > >> setting of ecutvcut. In the examples of Si, for pbe0-type hybrid > >> functional, the ecutvcut is set to be 0.7Ry, while for hse-type hybrid > >> functional with a screened Coulomb potential, ecutvcut is just set as > >> default which is 0.0Ry. Could anyone explain why? For a typical > >> semiconductor with s or p valence orbitals, what kind of ecutvcut value > >> is > >> recommended? > >> > >> Thanks a lot. > >> > >> best, > >> Jianpeng Liu > >> > >> - > >> Ph.D. candidate, > >> Department of physics and astronomy, > >> Rutgers University > >> - > >> > >> ___ > >> Pw_forum mailing list > >> Pw_forum at pwscf.org > >> http://pwscf.org/mailman/listinfo/pw_forum > >> > > ___ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://pwscf.org/mailman/listinfo/pw_forum > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > -- next part -- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20121122/c48721dd/attachment.html
[Pw_forum] HSE
Hi,
I would like to know exactly which "version" of HSE is implemented on
Quantum-ESPRESSO.
In the original HSE work a value for the screening parameter w is used, but on
an errata another value is given.
In recent publications they are usually called HSE03 (which uses
w_{HF}=0.15/sqrt(2) and w_{PBE}=0.15 x 2^(1/3) ) and HSE06
(w_{HF}=w_{PBE}=0.15).
Looking at the code insde funct.f90 I found "screening_parameter = 0.106",
which is the value of w_{HF} used on HSE03, which induces me to think that it's
this "version" that is implemented.
I couldn't find though if this value is used also for w_{PBE} (which would be a
mistake) or not (and w_{PBE} is corrected at a later point in calculation).
Can someone give me some info?
Thanks,
Leonardo Jorge
PhD Student
Instituto de F?sica, Universidade de S?o Paulo, Brazil
[Pw_forum] Problem with newly implemented LDA -1/2 in atomic code (ld1)
Hi, I'm Leonardo M M Jorge, the one who put the LDA-1/2 method on QE. And yes, it is working! You indeed have to create a new pseudopotential with ld1.x and the flag "iswitch=4" (among other options, shown in the example file atomic_doc/pseudo-LDA-0.5/si.lda.0.5.in ), and then use it on a standard LDA calculation. You obtained results very similar to standard LDA because one of these other options is not well set. When generating the pseudo, besides the electronic configuration used (of a half-ionized atom, hence the name -0.5 ), there is also another parameter needed: rcutv, which is the radius where you cut the perturbation. The value set on the example file (1.0) is too small; for Silicon these values should be somewhere around 3.6. To obtain the right value for this rcutv parameter you need to do several calculations, changing it by small steps, and then get the rcutv where the gap of the system is an extremum (maximum or minimum). The explanation why this works is written on the reference you just cited ( L. G. Ferreira, M. Marques and L. K. Teles, Phys. Rev. B 78 125116 (2008) ), but what's important is that it IS NOT a free parameter (one you keep changing until you get the result you want), as there is a procedure to obtain it. Also, as small variations of the rcutv parameters should give very small variations of the Electronic Gap (as it is an extremum for variations), we assume that you can obtain the right rcutv value for a small and simple system, and then use it on a bigger and more complex system (for a given atom; different atom kinds have different rcutv!). I hope I could explain the method for you, if you have any more questions feel free to write me. Leonardo Jorge PhD Student Universidade de S?o Paulo - Brazil
[Pw_forum] error in pseudopotential generation
With "pseudotype=1" you can use just one projector for each "L", and you used 2 "P"s and 2 "S"s. Leonardo Jorge Nanomol group Universidade de S?o Paulo, Brazil On Tue, Aug 24, 2010 at 10:14, mohaddeseh abbasnejad wrote: > > Dear users, > > I have faced this error while trying to generate a pseudopotential for Ti. > > ?%% > from ld1_readin : error # 1 > Two wavefunctions for the same l > ?%% > > Can any one tell me what's wrong? > > Thanks in advance. > > This is my input file: > > ? > ??? title='Ti', > ??? zed=22.0, > ??? rel=1, > ??? iswitch=3, > ??? rlderiv=2.50, > ??? eminld=-4.0, > ??? emaxld=4.0, > ??? deld=0.02, > ??? nld=5, > ??? config='[Ne] 3s2 3p6 3d2 4s2 4p0', > ??? dft='PBE' > ?/ > ? > ??? pseudotype=1 > ??? lloc=0, > ??? file_pseudopw='Ti.ncpp', > ?? ! nlcc=.true., > ?? ! rcore=0.8, > ?/ > 5 > 3D? 5? 2? 2.00? 0.00? 1.0 1.0 > 3P? 4? 1? 6.00? 0.00? 2.7 2.7 > 4P? 3? 1? 0.00? 0.00? 2.7 2.7 > 3S? 2? 0? 2.00 -0.00? 2.2 2.2 > 4S? 1? 0? 2.00 -0.00? 2.2 2.2 > > > > -- > - > > Mohaddeseh Abbasnejad, > Room No. 323, Department of Physics, > University of Tehran, North Karegar Ave., > Tehran, P.O. Box: 14395-547- IRAN > Tel. No.: +98 21 6111 8634? & Fax No.: +98 21 8800 4781 > Cellphone: +989177317514 > E-Mail:? ?? m.abbasnejad at gmail.com > Website:? http://physics.ut.ac.ir > > - > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > >
[Pw_forum] Fwd: different structure under xyz file and scf file for carbon nanotube
Hi, There is no problem on the coordinates, it's just a visualization "problem". In XCrysden change "Display -> Unit of Repetition -> Translational Asymmetric Unit". Keep in mind that in Espresso you have periodic boundary conditions, and so what you was seeing were the periodic images of each "quarter". Leonardo Jorge PhD Student USP - Brazil
[Pw_forum] Hirshfeld charges
Hello, My group is interested in calculating the Hirshfeld charges ( http://www.springerlink.com/content/h54771160812822j/ ) of some molecules. As it's not presently implemented on Espresso, I tried to write myself a code to calculate Hirshfeld charges, based on the existing voronoy code. But after some testing, I still can't get the results right (i.e. Silicon bulk is a bit charged). So I decided to write this e-mail to you: If someone else is interested in implementing Hirshfeld charges, please contact me and I will share my code, so we can make it work together. Thanks, Leonardo Jorge IF-USP, Brazil Nanomol group http://nanomol.if.usp.br
[Pw_forum] ab initio vs. first principles.
A small doubt that I had while following this discussion, please someone correct-me if I'm wrong: Is the following definition right? "[in ab-initio calculations we] do not make any assumption, such as > concerning models and/or fitting parameters." > I'm saying this because we use, for example, the homogeneous electron gas model for LDA calculations, nonetheless it is still "ab-initio". I think that it's not the use of parameters or models that define a first principles method, but from where those parameters were taken. If your parameters came from experimental values, it's somewhat empirical (or semi-empirical at least), if you used just theoretical values (even if using a simplified model) it can be called ab-initio. Is this right? This can even create some discussion if some new functionals can be called "ab-initio" or not... Leonardo Matheus IF-USP / Brazil -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20081221/0cb7751e/attachment.htm
[Pw_forum] Atomic rho
Thanks for your reply Axel. > well, for practical reasons it is more efficient to loop over > atom types and atoms per atom type. per atom-type parameters > only need to be computed once this way. I understand why the calculation is like this, but still couldn't find this "atoms per atom type" loop. > i suggest you first have a look into textbook material > explaining the implementation of electronic structure > calculation with plane wave pseudopotentials (e.g. the > books by jorge kohnoff or richard martin). and then > read the marx / hutter review which also gives an overview > on how the implementation can be done (on the example of > the CPMD code, which is not that different as far as the > basic principles are concerned). the CPMD code actually > does have an implementation of hirshfeld charges determination, > but only for norm-conserving pseudopotentials, IIRC, so you > can look up how the implementation principles. I've already read the book by Kohanoff, and now I'm waiting for the licence to download the CPMD code, to see how Hirshfeld charges are implemented there, thanks for the hint. ABINIT code also has Hirshfeld charges implemented, I'm looking there too. > for implementing it into QE you'll have to figure out > how to handle ultra-soft psps contribution to the atomic > density on top of everything else. I'm also using the SaX code, which accepts just NC PPs, so I haven't thought deeply on this, but I would first try to adapt the "addusdens" subroutine to the individual atomic densities (at least, this is what I understood the subroutine does). Actually, I've based most of my code on the "voronoy" program, so what I really need now is just to obtain the individual atomic rho, the rest (I think) is mostly done. > good luck, > axel. Thanks Leonardo Matheus Doctorate student - Physics Institute, University of S?o Paulo, Brazil Nanomol group - http://nanomol.if.usp.br
[Pw_forum] Atomic rho
Hello, I'm trying to calculate Hirshfeld charges as a postprocess. To do so, I need to obtain the atomic rho for each atom, in real space. I've seen that "atomic_rho.f90" calculates the total rho as a superposition of the individual atomic ones, obtained from the pseudopotentials. But I couldn't understand how this superposition is done, as the internal loop is based on atomic types, and not on individual atoms. I couldn't also find how the atomic coordinates are used (to "center" the charge on the atomic position), and which variable stores them. I saw that it was all done in reciprocal space, and probably this is where I'm confusing myself. Can someone please give me a hand? Thanks, Leonardo Matheus Doctorate student - Physics Institute, University of S?o Paulo, Brazil Nanomol group - http://nanomol.if.usp.br
