[QE-users] How can we decide the spin state of the relaxed structure
samala nagaprasad reddy
snpreddy63 at gmail.com
Wed Oct 28 10:38:39 CET 2020
Dear Andrii Shyichuk,
> From your magnetization data I can see that there is a significant
> spin-down on Co and some significant spin-ups on the other sites.
> This fact on itself indicates two or more magnetization sites, no matter
> what the total magnetization says. If you wanted it to be on Co only -
> well, it is not only there - as there are other sites.
>
> Please note that these values correspond to non-overlapping atomic
> spheres, meaning that actual Co magnetization is (much) higher than the
> displayed values.
>
Okay
>
> As to why in particular does it happen the way it happen - I do not have a
> precise answer.
> You may try pseudopotentials with spin-orbit coupling, or an all-electron
> code, or a molecular code (atomic-orbital based, non-periodic, e.g.
> Gaussian) just to see if you get the same result.
>
I have done the minimization of singlet and triplet using gaussian and the
triplet state is more stable than singlet.
Naga
>
> Best regards.
> Andrii
>
> W dniu 2020-10-27 09:38, samala nagaprasad reddy napisał:
>
> Dear Andrii Shyichuk,
>
> Thank you so much, for your detailed explanation.
>
>> 1. The starting magnetization result is weird.
>> There are apparently a few areas/centers of magnetization, summing up to
>> 2.77 absolute magnetization.
>> Some of them are up, and some of them are down, hence the total
>> magnetization (spin up minus spin down) is 0.3.
>>
>> Plot the magnetization to see what happens, while atomic magnetizations
>> can be found in the output file, after the SCF steps.
>> Same goes for the other results. Without the magnetization plot, you
>> cannot know if it is localized where it should be.
>>
>>
> From the starting_magnetization output, the Magnetic moment data is copied
> here. Atom 24 is Co.
> Magnetic moment per site:
> atom: 1 charge: 0.8381 magn: -0.0072 constr: 0.0000
> atom: 2 charge: 0.7359 magn: -0.0151 constr: 0.0000
> atom: 3 charge: 0.7788 magn: 0.0076 constr: 0.0000
> atom: 4 charge: 0.8093 magn: -0.0269 constr: 0.0000
> atom: 5 charge: 0.8320 magn: 0.0067 constr: 0.0000
> atom: 6 charge: 0.8322 magn: -0.0195 constr: 0.0000
> atom: 7 charge: 0.7581 magn: -0.0037 constr: 0.0000
> atom: 8 charge: 0.7590 magn: 0.0002 constr: 0.0000
> atom: 9 charge: 0.8329 magn: -0.0237 constr: 0.0000
> atom: 10 charge: 0.8393 magn: 0.0090 constr: 0.0000
> atom: 11 charge: 0.8295 magn: -0.0245 constr: 0.0000
> atom: 12 charge: 0.7706 magn: 0.0020 constr: 0.0000
> atom: 13 charge: 0.7626 magn: -0.0058 constr: 0.0000
> atom: 14 charge: 0.8298 magn: -0.0171 constr: 0.0000
> atom: 15 charge: 0.8408 magn: 0.0053 constr: 0.0000
> atom: 16 charge: 0.8308 magn: -0.0263 constr: 0.0000
> atom: 17 charge: 0.8158 magn: 0.0082 constr: 0.0000
> atom: 18 charge: 0.8036 magn: -0.0166 constr: 0.0000
> atom: 19 charge: 0.8416 magn: -0.0047 constr: 0.0000
> atom: 20 charge: 0.7640 magn: 0.0021 constr: 0.0000
> atom: 21 charge: 1.1987 magn: 0.0034 constr: 0.0000
> atom: 22 charge: 1.1930 magn: 0.0031 constr: 0.0000
> atom: 23 charge: 1.1107 magn: 0.0027 constr: 0.0000
> atom: 24 charge: 13.1659 magn: -0.2418 constr: 0.0000
> atom: 25 charge: 0.2760 magn: 0.0001 constr: 0.0000
> atom: 26 charge: 0.3021 magn: 0.0001 constr: 0.0000
> atom: 27 charge: 0.3101 magn: 0.0002 constr: 0.0000
> atom: 28 charge: 0.3305 magn: -0.0002 constr: 0.0000
> atom: 29 charge: 0.3365 magn: 0.0006 constr: 0.0000
> atom: 30 charge: 0.1946 magn: -0.0002 constr: 0.0000
> atom: 31 charge: 0.2463 magn: 0.0000 constr: 0.0000
> atom: 32 charge: 0.2932 magn: 0.0001 constr: 0.0000
> atom: 33 charge: 1.7268 magn: 0.1731 constr: 0.0000
> atom: 34 charge: 0.7468 magn: 0.0702 constr: 0.0000
> atom: 35 charge: 0.7615 magn: -0.0003 constr: 0.0000
> atom: 36 charge: 0.7542 magn: -0.0003 constr: 0.0000
> atom: 37 charge: 0.7593 magn: -0.0002 constr: 0.0000
> atom: 38 charge: 4.5377 magn: -0.0011 constr: 0.0000
> atom: 39 charge: 4.5690 magn: -0.0003 constr: 0.0000
> atom: 40 charge: 4.6764 magn: 0.0001 constr: 0.0000
> atom: 41 charge: 4.5738 magn: -0.0016 constr: 0.0000
> atom: 42 charge: 4.6399 magn: -0.0014 constr: 0.0000
> atom: 43 charge: 4.5299 magn: 0.0010 constr: 0.0000
> atom: 44 charge: 4.5786 magn: -0.0005 constr: 0.0000
> atom: 45 charge: 4.6315 magn: 0.0004 constr: 0.0000
> atom: 46 charge: 4.5206 magn: -0.0010 constr: 0.0000
> atom: 47 charge: 0.5296 magn: -0.0002 constr: 0.0000
> atom: 48 charge: 0.4843 magn: 0.0001 constr: 0.0000
> atom: 49 charge: 0.4805 magn: 0.0001 constr: 0.0000
> atom: 50 charge: 0.7915 magn: 0.0004 constr: 0.0000
>
> also for triplet
> Magnetic moment per site:
> atom: 1 charge: 0.8449 magn: 0.0240 constr: 0.0000
> atom: 2 charge: 0.8523 magn: 0.0012 constr: 0.0000
> atom: 3 charge: 0.8486 magn: 0.0115 constr: 0.0000
> atom: 4 charge: 0.8396 magn: 0.0167 constr: 0.0000
> atom: 5 charge: 0.8456 magn: 0.0011 constr: 0.0000
> atom: 6 charge: 0.8365 magn: 0.0249 constr: 0.0000
> atom: 7 charge: 0.8556 magn: -0.0025 constr: 0.0000
> atom: 8 charge: 0.8510 magn: 0.0182 constr: 0.0000
> atom: 9 charge: 0.8398 magn: 0.0083 constr: 0.0000
> atom: 10 charge: 0.8441 magn: 0.0092 constr: 0.0000
> atom: 11 charge: 0.8393 magn: 0.0207 constr: 0.0000
> atom: 12 charge: 0.8550 magn: -0.0019 constr: 0.0000
> atom: 13 charge: 0.8515 magn: 0.0209 constr: 0.0000
> atom: 14 charge: 0.8406 magn: 0.0016 constr: 0.0000
> atom: 15 charge: 0.8425 magn: 0.0181 constr: 0.0000
> atom: 16 charge: 0.8402 magn: 0.0121 constr: 0.0000
> atom: 17 charge: 0.8502 magn: 0.0036 constr: 0.0000
> atom: 18 charge: 0.8494 magn: 0.0218 constr: 0.0000
> atom: 19 charge: 0.8491 magn: -0.0025 constr: 0.0000
> atom: 20 charge: 1.3952 magn: 0.0006 constr: 0.0000
> atom: 21 charge: 1.3895 magn: 0.0006 constr: 0.0000
> atom: 22 charge: 1.3892 magn: 0.0015 constr: 0.0000
> atom: 23 charge: 1.3950 magn: 0.0021 constr: 0.0000
> atom: 24 charge: 14.3334 magn: -0.2847 constr: 0.0000
> atom: 25 charge: 0.4321 magn: 0.0003 constr: 0.0000
> atom: 26 charge: 0.4222 magn: -0.0010 constr: 0.0000
> atom: 27 charge: 0.4239 magn: 0.0000 constr: 0.0000
> atom: 28 charge: 0.4226 magn: -0.0011 constr: 0.0000
> atom: 29 charge: 0.4212 magn: -0.0003 constr: 0.0000
> atom: 30 charge: 0.4213 magn: -0.0011 constr: 0.0000
> atom: 31 charge: 0.4205 magn: -0.0002 constr: 0.0000
> atom: 32 charge: 0.4206 magn: -0.0007 constr: 0.0000
> atom: 33 charge: 0.4231 magn: 0.0000 constr: 0.0000
> atom: 34 charge: 0.4319 magn: 0.0002 constr: 0.0000
> atom: 35 charge: 0.4321 magn: 0.0004 constr: 0.0000
> atom: 36 charge: 0.4317 magn: 0.0004 constr: 0.0000
> atom: 37 charge: 0.7670 magn: -0.0001 constr: 0.0000
> atom: 38 charge: 0.7665 magn: -0.0004 constr: 0.0000
> atom: 39 charge: 0.7674 magn: -0.0008 constr: 0.0000
> atom: 40 charge: 4.6219 magn: 0.0002 constr: 0.0000
> atom: 41 charge: 4.6196 magn: 0.0034 constr: 0.0000
> atom: 42 charge: 4.6190 magn: 0.0010 constr: 0.0000
> atom: 43 charge: 4.6186 magn: 0.0036 constr: 0.0000
> atom: 44 charge: 4.6223 magn: 0.0006 constr: 0.0000
> atom: 45 charge: 4.6175 magn: 0.0028 constr: 0.0000
> atom: 46 charge: 4.6205 magn: 0.0013 constr: 0.0000
> atom: 47 charge: 4.6207 magn: 0.0041 constr: 0.0000
> atom: 48 charge: 4.6210 magn: 0.0015 constr: 0.0000
> atom: 49 charge: 3.0620 magn: 0.3267 constr: 0.0000
> atom: 50 charge: 3.0232 magn: 0.4564 constr: 0.0000
>
>> I assume that there is only one Co atom in the system, and the
>> magnetization should be localized there.
>> In the starting magnetization result, it is not.
>>
> Why is it not localized in the starting_magnetization results?
>
>>
>> 2. The triplet state has a lower energy, so yes, it looks more stable. Is
>> it also more stable in the experimental data?
>>
> No experimental data available.
>
>>
>> 3. I'd say, the better approach is the one giving you a reasonable result.
>> The tot_magnetization calculations are stable in a sense that they are
>> likely to converge with the desired magnetization.
>> The starting_magnetization are less stable from my experience: low-spin
>> states can converge from high-spin starting_magnetization.
>>
> I also felt the same from my experience, thanks for the confirmation.
>
> Thank you
> Naga
>
>>
>> Best regards.
>> Andrii Shyichuk
>>
>> W dniu 2020-10-21 09:52, samala nagaprasad reddy napisał:
>>
>> Hello QE experts,
>>
>> I am trying spin polarized DFT studies of Co-corrole complex using QE
>> (using just gamma point and large box size to avoid interactions), I am
>> relaxing the structure using nspin = 2 and starting_magnetization(6) =
>> 1.0, as initial guess of Co atom. At the end of relaxation I have observed
>> the below
>>
>> total magnetization = 0.31 Bohr mag/cell
>> absolute magnetization = 2.77 Bohr mag/cell
>> and Final energy = -1144.9536036757 Ry
>>
>> When I minimize the structure in singlet and triplet states by fixing the
>> total magnetization (non spin polarized gives singlet state, and used
>> tot_magnetization = 2 for triplet). The relaxed energies are
>> Final energy = -1144.9318071744 Ry (singlet)
>> Final energy = -1144.9537812641 Ry (triplet)
>>
>> Regarding this I have few queries
>> 1) what is the spin state of the relaxed complex with
>> starting_magnetization(6) = 1.0 (singlet/triplet or any other)? It seems
>> the electronic spin state is singlet bec the total magnetization is 0.31
>> and is close to 0.
>> 2) In the spin restricted calculations, the triplet state is more stable
>> than the singlet and how can we understand it from the above?
>> 3) which approach is better (whether the guess starting_magnetization or
>> by fixing the total magnetization)?
>>
>> Thanks in advance
>> Naga
>>
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>>
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>
>
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>
>
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