Yes, you understood correctly. It's probably why there is a block in the program for this case. The two Fermi levels don’t directly change the band energies themselves — they just control how the states are occupied in each spin channel. This is done to make sure the total number of electrons per cell and the target magnetisation are the ones given in input.
If you want to compare the bands or the DOS between the two channels, it’s best to shift the energies so that both Fermi levels are set to zero. That way, you’re looking at the band structures relative to a common reference, which makes the comparison much clearer. rom: users <users-boun...@lists.quantum-espresso.org> on behalf of Rameswar Bhattacharjee <rb1...@georgetown.edu> Sent: Monday, September 15, 2025 01:23 To: Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org> Subject: Re: [QE-users] Question on using bands.x with nspin=2 and total_magnetization=1 Der Pietro, If I understand correctly, you mean I have to use two fermi energies for alpha and beta channels to scale my (E-EF). I got two fermi energies from my nscf method and I am using them for my alpha and beta band, respectively. Please correct me if I am doing something wrong or missing something from your point. Thanks Rameswar On Wed, Sep 10, 2025 at 7:58 PM Pietro Davide Delugas <pdelu...@sissa.it<mailto:pdelu...@sissa.it>> wrote: Good. Remember that if you want to compare the bands of the two spin channels you will need also to shift with respect to the other so to that the two fermi levels match. Il 10 set 2025 10:36 PM, Rameswar Bhattacharjee <rb1...@georgetown.edu<mailto:rb1...@georgetown.edu>> ha scritto: Dear Pietro Thank you very much for your suggestions. Now I used this strategy for one system and got band structures for up and down electrons. I really appreciate your expert advice to solve this issue. Rameswar On Mon, Sep 8, 2025 at 1:25 PM Pietro Davide Delugas <pdelu...@sissa.it<mailto:pdelu...@sissa.it>> wrote: Dear Rameswar It is very simple open the file <prefix>.save/data-file-schema.xml search for a line like <two_fermi_energies>7.608312845405552E-001 5.253841076666873E-001</two_fermi_energies> and either remove it completely or comment it out like this <!--two_fermi_energies>7.608312845405552E-001 5.253841076666873E-001</two_fermi_energies—> Bands should then work fine. Pietro ________________________________ From: users <users-boun...@lists.quantum-espresso.org<mailto:users-boun...@lists.quantum-espresso.org>> on behalf of Rameswar Bhattacharjee <rb1...@georgetown.edu<mailto:rb1...@georgetown.edu>> Sent: Saturday, September 6, 2025 18:19 To: Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org>> Subject: Re: [QE-users] Question on using bands.x with nspin=2 and total_magnetization=1 Dear Pietro, I am sorry for my late response as I was out and had limited access to the internet. Thank you very much for your response. I tried to use total_magnetization for the scf and for the following nscf and bands, I removed that. However, as you suspected the error remains. I understand that you might fix it if I send you the xml file but I need to run several systems and am looking for a solution. Is there any way you can guide me to remove the error by myself? I can also send you the xml if you kindly fix it and let me know the steps. Thanks you Rameswar On Wed, Sep 3, 2025 at 10:50 AM Pietro Davide Delugas <pdelu...@sissa.it<mailto:pdelu...@sissa.it>> wrote: dear Rameswar The bands program is usually called after a pw run with calculation='bands'. This is a non-self-consistent calculation, so it is not necessary to specify the total magnetisation constraint in its input. pw reads the density, initialises the KS Hamiltonian and computes the eigenvalues. Removing total magnetisation will likely avoid the error. It might be, though, that the two Fermi levels are still reported in the XML file, and this may cause the bands to fail. in that case just send me the XML file, I will try to fix it manually. For the future, we will look into bands to see the reason for this block and remove it. pietro ________________________________ From: users <users-boun...@lists.quantum-espresso.org<mailto:users-boun...@lists.quantum-espresso.org>> on behalf of Rameswar Bhattacharjee <rb1...@georgetown.edu<mailto:rb1...@georgetown.edu>> Sent: Wednesday, September 3, 2025 16:33 To: Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org>> Subject: Re: [QE-users] Question on using bands.x with nspin=2 and total_magnetization=1 Dear QE community, I would greatly appreciate your advice on this. Basically, I am trying to perform a band structure calculation for a unit cell that contains an unpaired electron and is therefore paramagnetic. Could you please suggest the proper way to handle this setup? Thank you for your guidance. Best regards, On Sun, Aug 31, 2025 at 5:03 PM Rameswar Bhattacharjee <rb1...@georgetown.edu<mailto:rb1...@georgetown.edu>> wrote: Dear Dr Paulatto, Thank you very much for your response. Actually, the error I am getting is as below' --------------------------------------------------------- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Error in routine bands (1): The bands code with constrained magnetization has not been tested %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -------------------------------------------------------- And I was wrong earlier, the error also appears even if I do not use spin_component. I think this error shows as I have "total_magnetization=1" in my scf input. Now, my system has -2 charge and the spin multiplicity is 2. When I used starting_magnetization instead of total_magnetization, all the calculations were fine but I did not get the right magnetic moment as I expected. Basically, I did an scf, nscf, bands and then used a post procession calculation using bands.x to generate the ".dat" file for the band structure. The first three job competed successfully and the error appears only in the last post procession calculation for which the input is below: --------------- &BANDS prefix = 'crystal_from_cif', outdir='./scratch' filband = 'bands.dat' / --------------- I am also attaching the other inputs for you to take a quick look. Please note that the coordinates are not complete in the inputs I am also curious to know about your comment above "It depends on what you want to achieve." Could you please elaborate this a bit more? Your advice would be highly appreciated. Thanks Rameswar On Sun, Aug 31, 2025 at 3:54 PM Lorenzo Paulatto <lorenzo.paula...@cnrs.fr<mailto:lorenzo.paula...@cnrs.fr>> wrote: * Should I use the spin_component keyword to specify up-spin or down-spin bands, or is it recommended to simply run bands.x without this keyword? It depends on what you want to achieve. * I tried using spin_component=1 and 2, but I encountered errors in both cases. On the other hand, when I ran bands.x without the spin_component keyword, the job completed normally. Which error? Could you please advise on the correct way to handle this situation? Any guidance or clarification would be greatly appreciated. The correct way is to provide the full input and output of the calculation that is giving you trouble. And, more in general, if you think that a specific output is wrong, you should explain why you think so. kind regards Thank you in advance for your help. Best regards, Rameswar Bhattacharjee -- Rameswar Bhattacharjee Georgetown University Washington, DC 20057 _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org> https://lists.quantum-espresso.org/mailman/listinfo/users -- Dr. Lorenzo Paulatto IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN phone: +33 (0)1 442 79822 / telegram: lpaulatto http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/ 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05 _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org> https://lists.quantum-espresso.org/mailman/listinfo/users -- Rameswar Bhattacharjee Georgetown University Washington, DC 20057 -- Rameswar Bhattacharjee Assistant Research Professor Department of Chemistry Georgetown University Washington, DC 20057 _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org> https://lists.quantum-espresso.org/mailman/listinfo/users -- Rameswar Bhattacharjee Assistant Research Professor Department of Chemistry Georgetown University Washington, DC 20057 _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org> https://lists.quantum-espresso.org/mailman/listinfo/users -- Rameswar Bhattacharjee Assistant Research Professor Department of Chemistry Georgetown University Washington, DC 20057 _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list users@lists.quantum-espresso.org<mailto:users@lists.quantum-espresso.org> https://lists.quantum-espresso.org/mailman/listinfo/users -- Rameswar Bhattacharjee Assistant Research Professor Department of Chemistry Georgetown University Washington, DC 20057
_______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
