[Wien] optic sum rules
Dear Prof. Blaha I have calculated the optical properties of TiSe2 by MBJ potential with 6000, 5 and 9 kpoints which generated after scf by x kgen as discussed in the UG. As discussed in the paper of Prof. Claudia Draxl (computer physics comm. 175, 1-14 (2006)) the sum rule 1 and 2 show 'an effective number of electrons contributing to the absoption process as a function of energy'. but my calculations lead to : 6000 kpoints: sum rule 1: Int(sigma)dw 19.14 sum rule 2: Int(eloss.w)dw18.93 sum rule 3: Int(eloss/w)dw1.51 5 kpoints sum rule 1: Int(sigma)dw 19.08 sum rule 2: Int(eloss.w)dw18.94 sum rule 3: Int(eloss/w)dw1.52 9 kpoints sum rule 1: Int(sigma)dw 10.125 sum rule 2: Int(eloss.w)dw10.035 sum rule 3: Int(eloss/w)dw1.51 the results show that in 9 kpoints the value of 'sum rule 2' significantly decreases . in the UG it has mensioned that for the optic we need dense kpoints but how many? how can I check it for optic? Best Regards Ali___ 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] optic sum rules
There is definitely no need to go to such a high number of k-points. In the paper of Claudia, they were looking at metallic compounds, for which we need to have a very dense k-mesh (for the intraband transitions). In your case you expect a semiconductor and thus you will have only interband transitions. Thus 6000 kpoints is already converged to my point of view. I should say that the best way to insure the convergency in the present case is to plot the epsilon2 as a function of the energy for instance and to compare this quantity with different k-meshes. In your case, try to do 300 kpoints first and then 500, 1000, 2000, 3000 kpoints ... You will certainly reach the convergency at about 1000-2000 kpoints ... Regards Xavier P.S.: The values obtained for 9 kpoints are curious but I imagine that you had a prob Le 9/30/2013 4:59 PM, ali ghafari a écrit : Dear Prof. Blaha I have calculated the optical properties of TiSe2 by MBJ potential with 6000, 5 and 9 kpoints which generated after scf by x kgen as discussed in the UG. As discussed in the paper of Prof. Claudia Draxl (computer physics comm. 175, 1-14 (2006)) the sum rule 1 and 2 show 'an effective number of electrons contributing to the absoption process as a function of energy'. but my calculations lead to : 6000 kpoints: sum rule 1: Int(sigma)dw 19.14 sum rule 2: Int(eloss.w)dw18.93 sum rule 3: Int(eloss/w)dw1.51 5 kpoints sum rule 1: Int(sigma)dw 19.08 sum rule 2: Int(eloss.w)dw18.94 sum rule 3: Int(eloss/w)dw1.52 9 kpoints sum rule 1: Int(sigma)dw 10.125 sum rule 2: Int(eloss.w)dw10.035 sum rule 3: Int(eloss/w)dw1.51 the results show that in 9 kpoints the value of 'sum rule 2' significantly decreases . in the UG it has mensioned that for the optic we need dense kpoints but how many? how can I check it for optic? Best Regards Ali ___ 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 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] symmetso warns operation was not found in struct
Dear List, For a rhombohedral structure, I did `initso´ after converging a non-SO calculation. `symmetso´ complains (in the last section of `outsymmetso´): WARNING !! nsym found by symmetry differs from iord read in struct 12 4 Why does it say that? This would seem normal to be, since it is `symmetso´s job to reduce the symmetry. After that: Symmetry operation 2 0.50.866030.0 0.86603 -0.50.0 -0.00.0 -1.0 0.00.00.0 -1. -0. -0.0. 0.0. -1.0. 0. -1.0.0. WARNING ! this symmetry operation was not found in struct!! This kind of thing is repeated a couple of times. What does this mean? The last three lines of numbers specify a symmetry operation which *is* in fact in the struct file; what are the four lines before that? I am not very familiar with SO, nor with rhombohedral symmetry calculations, so I am unsure if it is safe to continue. The new `struct´ file created looks fine. It has 4 symmetry operations. The `ksym´ is empty, is that normal? Wow, that was a lot of questions. Thank you for you patience. Elias PS: I am using Wien2k13. ___ 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
