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Matter Modeling

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  • $\begingroup$ but the band energies should be the same between two spin channels, the result aren’t as it should be. $\endgroup$ Commented May 8, 2022 at 5:42
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    $\begingroup$ Why do you think the energies should be the same given this is an unrestricted calculation? $\endgroup$ Commented May 8, 2022 at 7:54
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    $\begingroup$ @Jack The band energies of the two spin channels are only equal when the net spin is zero, i.e. when the system respects time-reversal symmetry. Note that some textbooks may draw orbital diagrams in a way that alpha and beta orbital energy levels are the same even though the net spin is not zero, but strictly speaking this is an approximation. $\endgroup$ Commented May 8, 2022 at 8:58
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    $\begingroup$ Why are you talking about bands where do you have a single atom? Bands are only meaningful for periodical structures. $\endgroup$ Commented May 9, 2022 at 20:06
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    $\begingroup$ @Camps I agree with you conceptually and if we are being fully correct in terminology, however I think most people reading should understand these are orbital energies not bands. Maybe an edit to the original post clarifying terminology could be useful though. To be clear, VASP calls these band energies in the output so its up to the user to be aware band energies == orbital energies when the structure is not periodic $\endgroup$ Commented May 9, 2022 at 23:02