[Wien] Different Plasma Frequency (PF) for bulk and supercell Na
Dear Users I have computed PF for bulk Na and its value is *5.943 eV* with k-mesh *18*18*18*. Then I constructed a supercell 1*1*6 and run the calculation with different k-meshes and obtained PF values. The details are *K-meshPF (x/z components in eV)* *24*24*24 5.7097 / 5.8192* *36*36*24 5.7614 / 5.8098 * *50*50*10 5.9358 / 5.6280 * *50*50*30 5.9365 / 5.8079* My question is why PF is very sensitive to k-mesh selection? and which value of PF is required for correct dielectric constant calculation? Do I need *PF = 5.943 eV* for the supercell and then, definitely, need more test calculation for right k-mesh selection? -- Kind Regards Muhammad Sajjad Post Doctoral Fellow KAUST, KSA. ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
[Wien] analyse_phonon--"pos case not found" error
Dear Prof. Blaha, It is solved by means of your advice. Thanks Battal Gazi Yalcin Sakarya University Department of Physics Sakarya TURKEY ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] CHARGE DENSITY --> TOTAL CHARGE
On Mon, Oct 12, 2015 at 04:43:24AM -0500, Laurence Marks wrote: > Rather than giving the answer to the original question, I think it is > better to try and encourage people to solve problems themselves -- perhaps > I am being too much of an teacher, but that is my approach. > > So, let me pose a question in response to the original question. What is > the relationship between summing a set of values on a grid and the integral > of a function sampled at a set of grid points. Think about this, and the > reason why the numbers are very different will be obvious. > > If they still do not completely agree (they wont), then think about the > accuracy of numerical integration. It is quite important in DFT codes to > remember that numerical integrations are never exact, and this leads to > many small limitations. Laurence, I love your approach. May I continue? There are two main strategies in doing a numerical integration. The first is designing the geometry of the grid by simplicity and providing each grid point an equal weight. The alternative approach is far more complex, but it can also be more successful. The position and weight of grid points can be used to improve the quality of the integration. Best regards, Víctor Luaña ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] CHARGE DENSITY --> TOTAL CHARGE
Rather than giving the answer to the original question, I think it is better to try and encourage people to solve problems themselves -- perhaps I am being too much of an teacher, but that is my approach. So, let me pose a question in response to the original question. What is the relationship between summing a set of values on a grid and the integral of a function sampled at a set of grid points. Think about this, and the reason why the numbers are very different will be obvious. If they still do not completely agree (they wont), then think about the accuracy of numerical integration. It is quite important in DFT codes to remember that numerical integrations are never exact, and this leads to many small limitations. On Mon, Oct 12, 2015 at 3:39 AM, Elias Assmann wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA1 > > On 10/08/2015 07:34 PM, prasenjit roy wrote: > > I want to obtain the total number of electron in the unit cell, by > > summing over the total charge density within that unitcell and then > > match that number to the "atomic numbers times the respective > > multiplicity". Since WIen2K is full electron code, I expect these > > two be equal. > > I have never tried that, but I would expect the number to depend quite > sensitively on your mesh of r-points. At least, this is what I saw > when I looked at normalization of Wannier functions on an r-grid. > Since you want also the core electrons, you could actually expect even > larger spikes. > > > The system I worked on is : Mn6Fe6Si2P4 (total electron 394 in > > unitcell). When I summed up all the densities over the mesh (I > > chose 74*74*80 points), I obtained ~257050. > > However, this I would say sounds more like some missing factor … > Units? dV? > > > Elias > > > -BEGIN PGP SIGNATURE- > Version: GnuPG v1 > Comment: Using GnuPG with Icedove - http://www.enigmail.net/ > > iQIcBAEBAgAGBQJWG3HAAAoJEE/4gtQZfOqPmxoP/2pSiQe7vm2b5q9eyjN9X5VN > pQvq+RUE8F5pjgSK8W86YlRCFK34TIw3b8g7OvRW6noaeUGLqszWpFArfF0ToRE7 > +kS9+YcVLzoogCSoan5demVARHdP5oyKcv08NOpQBwndPYgvCAlPm+nN+Wg9T/m+ > b6znR2WzoXdLaMxK3uQW94fK+D/T2k4fDRSrd0rU5BU7FztzJ/qnbiywtZqnJbZ5 > mXUJCQuC+E5Uw1XGEvWR8XIisW5n/ZY1d27PHRStSG3utFbZxfdhxYpHHSAWX0di > SIO/DSfp1UGte3sfcjmtc41QFNBod1El6frLxNehmEhY4jMgsJRWST4qEblLdfk4 > fSz0cSRplff4WAQkiNUnFK2wiHtB/ZceiXDM1dxZmo76ItkyBMu0oDUpwpw75r3f > s+otHS2XPsMnd9knD0D7SXf5Ko3qNNR/Sj0hWBfpdPwHmDpg8k0clu23vGc6srWK > ISJrtABNcSDBuJp9IhURLc7VpbUCfKJ0WFXSLLorTXM5eb2oNJT+MPm4EDxK9zyQ > gaMcnV3nxoYYsNjgVwG4Du8XZO90T+Zc8AAdP7t1VW88QAMy85g9q1CH21AS3nnk > HSna4W7R3vTd2XP2cTQ2UYIKBzyBQYj/9HbNV7F0e5FlzMfirgPj3j2HVvTJLVYm > murT9xCL6Q8O0PH6SZHw > =Gwas > -END PGP SIGNATURE- > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > -- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu Corrosion in 4D: MURI4D.numis.northwestern.edu Co-Editor, Acta Cryst A "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Gyorgi ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
Re: [Wien] CHARGE DENSITY --> TOTAL CHARGE
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/08/2015 07:34 PM, prasenjit roy wrote: > I want to obtain the total number of electron in the unit cell, by > summing over the total charge density within that unitcell and then > match that number to the "atomic numbers times the respective > multiplicity". Since WIen2K is full electron code, I expect these > two be equal. I have never tried that, but I would expect the number to depend quite sensitively on your mesh of r-points. At least, this is what I saw when I looked at normalization of Wannier functions on an r-grid. Since you want also the core electrons, you could actually expect even larger spikes. > The system I worked on is : Mn6Fe6Si2P4 (total electron 394 in > unitcell). When I summed up all the densities over the mesh (I > chose 74*74*80 points), I obtained ~257050. However, this I would say sounds more like some missing factor … Units? dV? Elias -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iQIcBAEBAgAGBQJWG3HAAAoJEE/4gtQZfOqPmxoP/2pSiQe7vm2b5q9eyjN9X5VN pQvq+RUE8F5pjgSK8W86YlRCFK34TIw3b8g7OvRW6noaeUGLqszWpFArfF0ToRE7 +kS9+YcVLzoogCSoan5demVARHdP5oyKcv08NOpQBwndPYgvCAlPm+nN+Wg9T/m+ b6znR2WzoXdLaMxK3uQW94fK+D/T2k4fDRSrd0rU5BU7FztzJ/qnbiywtZqnJbZ5 mXUJCQuC+E5Uw1XGEvWR8XIisW5n/ZY1d27PHRStSG3utFbZxfdhxYpHHSAWX0di SIO/DSfp1UGte3sfcjmtc41QFNBod1El6frLxNehmEhY4jMgsJRWST4qEblLdfk4 fSz0cSRplff4WAQkiNUnFK2wiHtB/ZceiXDM1dxZmo76ItkyBMu0oDUpwpw75r3f s+otHS2XPsMnd9knD0D7SXf5Ko3qNNR/Sj0hWBfpdPwHmDpg8k0clu23vGc6srWK ISJrtABNcSDBuJp9IhURLc7VpbUCfKJ0WFXSLLorTXM5eb2oNJT+MPm4EDxK9zyQ gaMcnV3nxoYYsNjgVwG4Du8XZO90T+Zc8AAdP7t1VW88QAMy85g9q1CH21AS3nnk HSna4W7R3vTd2XP2cTQ2UYIKBzyBQYj/9HbNV7F0e5FlzMfirgPj3j2HVvTJLVYm murT9xCL6Q8O0PH6SZHw =Gwas -END PGP SIGNATURE- ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
