### Re: [Wien] force difference between LAPW and PAW method

I would expect there to be slight differences in the energy versus cell for the two approaches, which could easily lead to forces. That said, I doubt that the forces will have any effect on what you are trying to calculate. Do a simple test such as a small TiO2 supercell and displace an O. --- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University http://www.numis.northwestern.edu Corrosion in 4D http://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 On Jan 29, 2016 10:04, "pavel.ondra...@email.cz" <pavel.ondra...@email.cz> wrote: > > -- Původní zpráva -- > Od: Laurence Marks <laurence.ma...@gmail.com> > Komu: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> > Datum: 29. 1. 2016 13:34:23 > Předmět: Re: [Wien] force difference between LAPW and PAW method > > Did you check the absolute cell size for the two - minimize the energy > w.r.t. size? > > > The absolute cell size was fixed (same in both softwares of course) and > was calculated using experimental densities for the mixtures. No > minimization with respect to cell volume was done, however I would expect > it to be near equilibrium. My main goal with those cells is to calculate > the XPS shifts of O1s peak (using the slater transition state method) to > help in evaluation of some experimental XPS data, so I wanted to stick with > the experimental densities. > > > Would some stress in the cell explain the difference between the methods? > ___ 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] force difference between LAPW and PAW method

Did you check for lattice parameter changes? A relatively small change for a single unit cell can translate to something larger. Unfortunately you need a reference compound, which is not so simple in your case. Perhaps test SiO2, TiO2 & a few simple similar compounds with the PAW & Wien2k. --- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University http://www.numis.northwestern.edu Corrosion in 4D http://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 On Jan 29, 2016 03:50, "Pavel Ondračka"wrote: > Dear Wien2k mailing list, > > I've been doing some calculation on a moderately large (around 100 > atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing > MD in a PAW software. According to my colleague who did the final force > relaxation, the residual forces on atoms should be around 0.5 > mRyd/Bohr. However when I calculate forces in Wien2k I see forces of > order of magnitude larger, eg. some as large as 30mRyd/Bohr. > > This are exactly the same calculations: both using PBE, same k-grid, > same RKMAX (calculated from cutoff using the formula from UG) and I've > spent a lot of time checking the force convergence with respect to all > possible parameters. > > We did some tests with small cells (eg. 10 atoms) and there we can get > a consistent results with max difference of forces around 10-20% which > I find reasonable. I'm actually quite clueless about it. I've been > suspecting user error at the beginning however I haven't found any so > far. My current theory is that in this large cases without symmetry > maybe the small differences between methods somehow sum up and hence > the big difference in final forces, however I would like to hear your > opinion in this matter. > > Best regards > Pavel Ondračka > ___ > 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] force difference between LAPW and PAW method

If the disordered compound goes metallic ??? it could be a problem. The default WIEN2k is using TETRA, while VASP uses a large broadening. Again, forget the 400 eV of the PAW calculation. It has NOTHING to do with our RKmax and our basis sets are usually more efficient. In any case, RKMAX=8.5 is "more than overconverged", since your smallest sphere is probably Oxygen. I'd start such a calculation with RKMAX=5 and later check with 6 and/or 7. Another possible problem: SiO2 might have small spheres for Si leading to quite some core leakage ??? Either use .lcore or put the Si-2p as semicore ! On 01/29/2016 12:04 PM, Pavel Ondračka wrote: Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100: This looks fairly large. I do NOT understand your statement of using "the same RKMAX" ??? PAW does not have RKMAX and their KMAX has NOTHING to do with ours. What was your RKMAX and what are youre sphere sizes ??? Sorry, the right word should probably be "equivalent RKMAX". As mentioned in the original email, the RKMAX was calculated from cutoff in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of smallest sphere). Specific values differed between cells, smallest spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of 400eV). k-mesh: not only the grid is important ! As far as I know, VASP usually uses a "huge" temperature broadening. What FERMI-method are you using ? default spin-polarization ?? no Is the PAW done with VASP and a fairly new release (accurate PAW potentials ?) It was VASP and it was one of the latest versions. Will check for specifics. On 01/29/2016 10:50 AM, Pavel Ondračka wrote: Dear Wien2k mailing list, I've been doing some calculation on a moderately large (around 100 atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing MD in a PAW software. According to my colleague who did the final force relaxation, the residual forces on atoms should be around 0.5 mRyd/Bohr. However when I calculate forces in Wien2k I see forces of order of magnitude larger, eg. some as large as 30mRyd/Bohr. This are exactly the same calculations: both using PBE, same k- grid, same RKMAX (calculated from cutoff using the formula from UG) and I've spent a lot of time checking the force convergence with respect to all possible parameters. We did some tests with small cells (eg. 10 atoms) and there we can get a consistent results with max difference of forces around 10-20% which I find reasonable. I'm actually quite clueless about it. I've been suspecting user error at the beginning however I haven't found any so far. My current theory is that in this large cases without symmetry maybe the small differences between methods somehow sum up and hence the big difference in final forces, however I would like to hear your opinion in this matter. Best regards Pavel Ondračka ___ 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 -- P.Blaha -- Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php -- ___ 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] force difference between LAPW and PAW method

Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100: > This looks fairly large. > > I do NOT understand your statement of using "the same RKMAX" ??? > PAW does not have RKMAX and their KMAX has NOTHING to do with ours. > What was your RKMAX and what are youre sphere sizes ??? Sorry, the right word should probably be "equivalent RKMAX". As mentioned in the original email, the RKMAX was calculated from cutoff in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of smallest sphere). Specific values differed between cells, smallest spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of 400eV). > > k-mesh: not only the grid is important ! As far as I know, VASP > usually > uses a "huge" temperature broadening. What FERMI-method are you using > ? default > spin-polarization ?? no > Is the PAW done with VASP and a fairly new release (accurate PAW > potentials ?) It was VASP and it was one of the latest versions. Will check for specifics. > > On 01/29/2016 10:50 AM, Pavel Ondračka wrote: > > Dear Wien2k mailing list, > > > > I've been doing some calculation on a moderately large (around 100 > > atoms) amorphous-like SixTi1-xO2 cells produced by simulated > > annealing > > MD in a PAW software. According to my colleague who did the final > > force > > relaxation, the residual forces on atoms should be around 0.5 > > mRyd/Bohr. However when I calculate forces in Wien2k I see forces > > of > > order of magnitude larger, eg. some as large as 30mRyd/Bohr. > > > > This are exactly the same calculations: both using PBE, same k- > > grid, > > same RKMAX (calculated from cutoff using the formula from UG) and > > I've > > spent a lot of time checking the force convergence with respect to > > all > > possible parameters. > > > > We did some tests with small cells (eg. 10 atoms) and there we can > > get > > a consistent results with max difference of forces around 10-20% > > which > > I find reasonable. I'm actually quite clueless about it. I've been > > suspecting user error at the beginning however I haven't found any > > so > > far. My current theory is that in this large cases without symmetry > > maybe the small differences between methods somehow sum up and > > hence > > the big difference in final forces, however I would like to hear > > your > > opinion in this matter. > > > > Best regards > > Pavel Ondračka > > ___ > > 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] force difference between LAPW and PAW method

Did you check the absolute cell size for the two - minimize the energy w.r.t. size? --- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University http://www.numis.northwestern.edu Corrosion in 4D http://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 On Jan 29, 2016 04:38, "Pavel Ondračka"wrote: > Laurence Marks píše v Pá 29. 01. 2016 v 04:22 -0600: > > Did you check for lattice parameter changes? A relatively small > > change for a single unit cell can translate to something larger. > > Unfortunately you need a reference compound, which is not so simple > > in your case. Perhaps test SiO2, TiO2 & a few simple similar > > compounds with the PAW & Wien2k. > > Yeah, some difference in cell size or positions was one of my suspects. > I usually use VESTA to read the structure file from PAW software, then > output to cif and use cif2struct to convert to struct and I was > suspecting that maybe somewhere in this process I lose precision. > So I've actually written a small python script to convert it directly > with full precision allowed by the struct format, however the result > were almost identical. > Regarding the test cases, we tested eg. with rutile (with one atom > slightly displaced to induce some forces) and the result were > comparable (few percent difference). > > Best regards > Pavel Ondračka > ___ > 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] force difference between LAPW and PAW method

Maybe one should use in VASP also a PAW potential which has Si-2p as valence. On 01/29/2016 12:47 PM, pavel.ondra...@email.cz wrote: -- Původní zpráva -- Od: Peter Blaha <pbl...@theochem.tuwien.ac.at> Komu: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> Datum: 29. 1. 2016 12:18:58 Předmět: Re: [Wien] force difference between LAPW and PAW method If the disordered compound goes metallic ??? it could be a problem. The default WIEN2k is using TETRA, while VASP uses a large broadening. The resulting structure has gap at least as large as TiO2. Again, forget the 400 eV of the PAW calculation. It has NOTHING to do with our RKmax and our basis sets are usually more efficient. In any case, RKMAX=8.5 is "more than overconverged", since your smallest sphere is probably Oxygen. I'd start such a calculation with RKMAX=5 and later check with 6 and/or 7. True, for usual calculations I use value RKMAX around 7.0 for such compounds, I went to 8.0 just for convergence checking purposes. However average differences in forces between 7.0 and 8.0 were quite small < 0.2mRyd/Bohr Another possible problem: SiO2 might have small spheres for Si leading to quite some core leakage ??? Either use .lcore or put the Si-2p as semicore ! Indeed I've noticed that silicon gets very small sphere especially with the new scheme in setrm. I'm using the "original" scheme, where the Si usually gets same sphere as O, around 1.5. Also Si2-p states were chosen as semicore. No core leakage warnings in logs. On 01/29/2016 12:04 PM, Pavel Ondračka wrote: > Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100: >> This looks fairly large. >> >> I do NOT understand your statement of using "the same RKMAX" ??? >> PAW does not have RKMAX and their KMAX has NOTHING to do with ours. >> What was your RKMAX and what are youre sphere sizes ??? > > Sorry, the right word should probably be "equivalent RKMAX". As > mentioned in the original email, the RKMAX was calculated from cutoff > in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of > smallest sphere). Specific values differed between cells, smallest > spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of > 400eV). >> >> k-mesh: not only the grid is important ! As far as I know, VASP >> usually >> uses a "huge" temperature broadening. What FERMI-method are you using >> ? > > default > >> spin-polarization ?? > > no > >> Is the PAW done with VASP and a fairly new release (accurate PAW >> potentials ?) > > It was VASP and it was one of the latest versions. Will check for > specifics. > >> >> On 01/29/2016 10:50 AM, Pavel Ondračka wrote: >>> Dear Wien2k mailing list, >>> >>> I've been doing some calculation on a moderately large (around 100 >>> atoms) amorphous-like SixTi1-xO2 cells produced by simulated >>> annealing >>> MD in a PAW software. According to my colleague who did the final >>> force >>> relaxation, the residual forces on atoms should be around 0.5 >>> mRyd/Bohr. However when I calculate forces in Wien2k I see forces >>> of >>> order of magnitude larger, eg. some as large as 30mRyd/Bohr. >>> >>> This are exactly the same calculations: both using PBE, same k- >>> grid, >>> same RKMAX (calculated from cutoff using the formula from UG) and >>> I've >>> spent a lot of time checking the force convergence with respect to >>> all >>> possible parameters. >>> >>> We did some tests with small cells (eg. 10 atoms) and there we can >>> get >>> a consistent results with max difference of forces around 10-20% >>> which >>> I find reasonable. I'm actually quite clueless about it. I've been >>> suspecting user error at the beginning however I haven't found any >>> so >>> far. My current theory is that in this large cases without symmetry >>> maybe the small differences between methods somehow sum up and >>> hence >>> the big difference in final forces, however I would like to hear >>> your >>> opinion in this matter. >>> >>> Best regards >>> Pavel Ondračka >>> ___

### Re: [Wien] force difference between LAPW and PAW method

Laurence Marks píše v Pá 29. 01. 2016 v 04:22 -0600: > Did you check for lattice parameter changes? A relatively small > change for a single unit cell can translate to something larger. > Unfortunately you need a reference compound, which is not so simple > in your case. Perhaps test SiO2, TiO2 & a few simple similar > compounds with the PAW & Wien2k. Yeah, some difference in cell size or positions was one of my suspects. I usually use VESTA to read the structure file from PAW software, then output to cif and use cif2struct to convert to struct and I was suspecting that maybe somewhere in this process I lose precision. So I've actually written a small python script to convert it directly with full precision allowed by the struct format, however the result were almost identical. Regarding the test cases, we tested eg. with rutile (with one atom slightly displaced to induce some forces) and the result were comparable (few percent difference). Best regards Pavel Ondračka ___ 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] force difference between LAPW and PAW method

This looks fairly large. I do NOT understand your statement of using "the same RKMAX" ??? PAW does not have RKMAX and their KMAX has NOTHING to do with ours. What was your RKMAX and what are youre sphere sizes ??? k-mesh: not only the grid is important ! As far as I know, VASP usually uses a "huge" temperature broadening. What FERMI-method are you using ? spin-polarization ?? Is the PAW done with VASP and a fairly new release (accurate PAW potentials ?) On 01/29/2016 10:50 AM, Pavel Ondračka wrote: Dear Wien2k mailing list, I've been doing some calculation on a moderately large (around 100 atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing MD in a PAW software. According to my colleague who did the final force relaxation, the residual forces on atoms should be around 0.5 mRyd/Bohr. However when I calculate forces in Wien2k I see forces of order of magnitude larger, eg. some as large as 30mRyd/Bohr. This are exactly the same calculations: both using PBE, same k-grid, same RKMAX (calculated from cutoff using the formula from UG) and I've spent a lot of time checking the force convergence with respect to all possible parameters. We did some tests with small cells (eg. 10 atoms) and there we can get a consistent results with max difference of forces around 10-20% which I find reasonable. I'm actually quite clueless about it. I've been suspecting user error at the beginning however I haven't found any so far. My current theory is that in this large cases without symmetry maybe the small differences between methods somehow sum up and hence the big difference in final forces, however I would like to hear your opinion in this matter. Best regards Pavel Ondračka ___ 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 -- P.Blaha -- Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php -- ___ 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] force difference between LAPW and PAW method

-- Původní zpráva -- Od: Peter Blaha <pbl...@theochem.tuwien.ac.at> Komu: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> Datum: 29. 1. 2016 12:18:58 Předmět: Re: [Wien] force difference between LAPW and PAW method "If the disordered compound goes metallic ??? it could be a problem. The default WIEN2k is using TETRA, while VASP uses a large broadening." The resulting structure has gap at least as large as TiO2. " Again, forget the 400 eV of the PAW calculation. It has NOTHING to do with our RKmax and our basis sets are usually more efficient. In any case, RKMAX=8.5 is "more than overconverged", since your smallest sphere is probably Oxygen. I'd start such a calculation with RKMAX=5 and later check with 6 and/or 7." "" True, for usual calculations I use value RKMAX around 7.0 for such compounds, I went to 8.0 just for convergence checking purposes. However average differences in forces between 7.0 and 8.0 were quite small < 0.2 mRyd/Bohr " Another possible problem: SiO2 might have small spheres for Si leading to quite some core leakage ??? Either use .lcore or put the Si-2p as semicore !" Indeed I've noticed that silicon gets very small sphere especially with the new scheme in setrm. I'm using the "original" scheme, where the Si usually gets same sphere as O, around 1.5. Also Si2-p states were chosen as semicore. No core leakage warnings in logs. " On 01/29/2016 12:04 PM, Pavel Ondračka wrote: > Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100: >> This looks fairly large. >> >> I do NOT understand your statement of using "the same RKMAX" ??? >> PAW does not have RKMAX and their KMAX has NOTHING to do with ours. >> What was your RKMAX and what are youre sphere sizes ??? > > Sorry, the right word should probably be "equivalent RKMAX". As > mentioned in the original email, the RKMAX was calculated from cutoff > in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of > smallest sphere). Specific values differed between cells, smallest > spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of > 400eV). >> >> k-mesh: not only the grid is important ! As far as I know, VASP >> usually >> uses a "huge" temperature broadening. What FERMI-method are you using >> ? > > default > >> spin-polarization ?? > > no > >> Is the PAW done with VASP and a fairly new release (accurate PAW >> potentials ?) > > It was VASP and it was one of the latest versions. Will check for > specifics. > >> >> On 01/29/2016 10:50 AM, Pavel Ondračka wrote: >>> Dear Wien2k mailing list, >>> >>> I've been doing some calculation on a moderately large (around 100 >>> atoms) amorphous-like SixTi1-xO2 cells produced by simulated >>> annealing >>> MD in a PAW software. According to my colleague who did the final >>> force >>> relaxation, the residual forces on atoms should be around 0.5 >>> mRyd/Bohr. However when I calculate forces in Wien2k I see forces >>> of >>> order of magnitude larger, eg. some as large as 30mRyd/Bohr. >>> >>> This are exactly the same calculations: both using PBE, same k- >>> grid, >>> same RKMAX (calculated from cutoff using the formula from UG) and >>> I've >>> spent a lot of time checking the force convergence with respect to >>> all >>> possible parameters. >>> >>> We did some tests with small cells (eg. 10 atoms) and there we can >>> get >>> a consistent results with max difference of forces around 10-20% >>> which >>> I find reasonable. I'm actually quite clueless about it. I've been >>> suspecting user error at the beginning however I haven't found any >>> so >>> far. My current theory is that in this large cases without symmetry >>> maybe the small differences between methods somehow sum up and >>> hence >>> the big difference in final forces, however I would like to hear >>> your >>> opinion in this matter. >>> >>> Best regards >>> Pavel Ondračka >>> ___ >>> 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 >

### Re: [Wien] force difference between LAPW and PAW method

-- Původní zpráva -- Od: Laurence Marks <laurence.ma...@gmail.com> Komu: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> Datum: 29. 1. 2016 13:34:23 Předmět: Re: [Wien] force difference between LAPW and PAW method " Did you check the absolute cell size for the two - minimize the energy w.r. t. size? " The absolute cell size was fixed (same in both softwares of course) and was calculated using experimental densities for the mixtures. No minimization with respect to cell volume was done, however I would expect it to be near equilibrium. My main goal with those cells is to calculate the XPS shifts of O1s peak (using the slater transition state method) to help in evaluation of some experimental XPS data, so I wanted to stick with the experimental densities. Would some stress in the cell explain the difference between the methods? ___ 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] force difference between LAPW and PAW method

-- Původní zpráva -- Od: Peter Blaha <pbl...@theochem.tuwien.ac.at> Komu: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> Datum: 29. 1. 2016 12:56:20 Předmět: Re: [Wien] force difference between LAPW and PAW method "Maybe one should use in VASP also a PAW potential which has Si-2p as valence. "" " Thanks for the advice, we will try this. ___ 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