Re: [Wien] consistent RKmax and sphere size settings
Three comments: RMT consistency is in particular important for total energies. If you compare the energy of 2 phases and their energy difference is just a few mRy, make sure you really have consistent RMTs and RKmax. Since the scaling with RKmax is not perfect, it might be wrong enough to lead to a wrong ground state (in particular when you are using a rather low RKmax value - with a fully converged RKmax the RMT dependency is reduced (except for possible core leakage !) You mentioned core level shifts. This is something you simply have to test yourself. My expectation is, that it is NOT very crucial, as long as you have at least "similar" convergence. Calculate the core level shifts for one compound with large and small RMT and compare the results. If they are the same within acceptable errors, you can forget RMT problems for this property. I'd expect that this should be general enough except when you have a very exotic compound. lmax is uncritical, but for larger spheres lvns may have a larger influence as well as linearization errors (HDLOs for d or f electrons and large spheres), while GMAX may also be important for small spheres. Am 08.04.2021 um 07:18 schrieb Pavel Ondračka: Thank you Laurence, I was a bit worried because the FAQ you linked also says: "Of course you should use identical Mg+O spheres for MgO and Mg(OH)2 for consistency", so I was not 100% sure if keeping the same maximum K- vector Kmax is enough. Should I also increase lmax and lvns for the larger spheres somehow? Or would you keep it the same for small and large N spheres? Best regards Pavel On Wed, 2021-04-07 at 15:33 -0500, Laurence Marks wrote: Have a look at http://www.wien2k.at/reg_user/faq/rkmax.html. If (say) with an RMT for the N of 1.6 a RKMAX of 6.5 is good enough, then when you reduce the RMT to 1.3 you can reduce the RKMAX to 6.5*1.3/1.6 = 5.28. This will not give you precisely the same relative convergence, but is close. Another way is to say that an RKMAX of 7 is "OK" for RMTs of 2.0, an RKMAX of 3 for RMTs of 0.5, then interpolate using a straight line. This is similar. On Wed, Apr 7, 2021 at 3:24 PM Pavel Ondračka wrote: Dear Wien2k mailing list, I have a series of TiN and TiON amorphous-like structures where I have some large differences in spheres sizes for N atoms. In most of the structures the smallest N sphere is around 1.6-1.7, however in some I have few N atoms with 1.3 (the structures should be OK, this much smaller size is due to some rare local configuration which would correspond to something like N split interstitial in crystalline structure). My goal is to calculate core electron binding energies of N1s levels of many atoms in the structures (at least 200 core-hole calculations) and I need to be consistent over different structures in the series. So usually I would just check what is the smallest N sphere size in the whole set, and force it for all N atoms in all structures and than use the identical RKmax for all structures, just to be sure I'm consistent. This is unfortunatelly not very efficient with respect to the calculation speed as I have quite large cells (around 150 atoms). Is there another way how can I save some CPU time and keep the consistency? I was for example thinking if I can force somehow two different N sphere sizes (one for the N split intestitial, which I have usually just one in the whole cell and one larger for the rest of N atoms), than I would have consistent sphere size for the rest of N atoms in the series and I could change the RKmax to keep the same largest K- vector which should be enough to guarantee consistency for all N atoms expect the split interstitials (but I don't care that much about them). However as far as I understand this is not possible? Any ideas would be appreciated. Best regards Pavel Ondracka ___ Wien mailing list Wien@zeus.theochem.tuwien.ac.at https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwzDI3sKJg$ SEARCH the MAILING-LIST at: https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwypwEJ3kA$ ___ 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 -- -- Peter BLAHA, Inst.f. Materials Chemistry,
Re: [Wien] consistent RKmax and sphere size settings
Thank you Laurence, I was a bit worried because the FAQ you linked also says: "Of course you should use identical Mg+O spheres for MgO and Mg(OH)2 for consistency", so I was not 100% sure if keeping the same maximum K- vector Kmax is enough. Should I also increase lmax and lvns for the larger spheres somehow? Or would you keep it the same for small and large N spheres? Best regards Pavel On Wed, 2021-04-07 at 15:33 -0500, Laurence Marks wrote: > Have a look at http://www.wien2k.at/reg_user/faq/rkmax.html. If (say) > with an RMT for the N of 1.6 a RKMAX of 6.5 is good enough, then when > you reduce the RMT to 1.3 you can reduce the RKMAX to 6.5*1.3/1.6 = > 5.28. This will not give you precisely the same relative convergence, > but is close. > > Another way is to say that an RKMAX of 7 is "OK" for RMTs of 2.0, an > RKMAX of 3 for RMTs of 0.5, then interpolate using a straight line. > This is similar. > > On Wed, Apr 7, 2021 at 3:24 PM Pavel Ondračka > wrote: > > Dear Wien2k mailing list, > > > > I have a series of TiN and TiON amorphous-like structures where I > > have > > some large differences in spheres sizes for N atoms. In most of the > > structures the smallest N sphere is around 1.6-1.7, however in some > > I > > have few N atoms with 1.3 (the structures should be OK, this much > > smaller size is due to some rare local configuration which would > > correspond to something like N split interstitial in crystalline > > structure). > > > > My goal is to calculate core electron binding energies of N1s > > levels > > of > > many atoms in the structures (at least 200 core-hole calculations) > > and > > I need to be consistent over different structures in the series. > > > > So usually I would just check what is the smallest N sphere size in > > the > > whole set, and force it for all N atoms in all structures and than > > use > > the identical RKmax for all structures, just to be sure I'm > > consistent. > > This is unfortunatelly not very efficient with respect to the > > calculation speed as I have quite large cells (around 150 atoms). > > Is > > there another way how can I save some CPU time and keep the > > consistency? > > > > I was for example thinking if I can force somehow two different N > > sphere sizes (one for the N split intestitial, which I have usually > > just one in the whole cell and one larger for the rest of N atoms), > > than I would have consistent sphere size for the rest of N atoms in > > the > > series and I could change the RKmax to keep the same largest K- > > vector > > which should be enough to guarantee consistency for all N atoms > > expect > > the split interstitials (but I don't care that much about them). > > However as far as I understand this is not possible? > > > > Any ideas would be appreciated. > > > > Best regards > > Pavel Ondracka > > > > ___ > > Wien mailing list > > Wien@zeus.theochem.tuwien.ac.at > > https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwzDI3sKJg$ > > > > SEARCH the MAILING-LIST at: > > https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwypwEJ3kA$ > > > > > ___ > 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
Re: [Wien] consistent RKmax and sphere size settings
Have a look at http://www.wien2k.at/reg_user/faq/rkmax.html. If (say) with an RMT for the N of 1.6 a RKMAX of 6.5 is good enough, then when you reduce the RMT to 1.3 you can reduce the RKMAX to 6.5*1.3/1.6 = 5.28. This will not give you precisely the same relative convergence, but is close. Another way is to say that an RKMAX of 7 is "OK" for RMTs of 2.0, an RKMAX of 3 for RMTs of 0.5, then interpolate using a straight line. This is similar. On Wed, Apr 7, 2021 at 3:24 PM Pavel Ondračka wrote: > Dear Wien2k mailing list, > > I have a series of TiN and TiON amorphous-like structures where I have > some large differences in spheres sizes for N atoms. In most of the > structures the smallest N sphere is around 1.6-1.7, however in some I > have few N atoms with 1.3 (the structures should be OK, this much > smaller size is due to some rare local configuration which would > correspond to something like N split interstitial in crystalline > structure). > > My goal is to calculate core electron binding energies of N1s levels of > many atoms in the structures (at least 200 core-hole calculations) and > I need to be consistent over different structures in the series. > > So usually I would just check what is the smallest N sphere size in the > whole set, and force it for all N atoms in all structures and than use > the identical RKmax for all structures, just to be sure I'm consistent. > This is unfortunatelly not very efficient with respect to the > calculation speed as I have quite large cells (around 150 atoms). Is > there another way how can I save some CPU time and keep the > consistency? > > I was for example thinking if I can force somehow two different N > sphere sizes (one for the N split intestitial, which I have usually > just one in the whole cell and one larger for the rest of N atoms), > than I would have consistent sphere size for the rest of N atoms in the > series and I could change the RKmax to keep the same largest K-vector > which should be enough to guarantee consistency for all N atoms expect > the split interstitials (but I don't care that much about them). > However as far as I understand this is not possible? > > Any ideas would be appreciated. > > Best regards > Pavel Ondracka > > ___ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > > https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwzDI3sKJg$ > SEARCH the MAILING-LIST at: > https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!CmcMwWJhVAKhTUEoDt5KIyqaJX5T80I6NHismOuUzcHH0sD9lAytg75A7qoRWwypwEJ3kA$ > -- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi ___ 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