[QE-users] What is the difference between ILDOS and |psi|^2?

[Stefano Baroni]

Dear Toshiharu: The ILDOS sums the squared moduli of all the molecular orbitals in a given energy range. px, py, and pz are degenerate, and their square modulus spherically symmetric (can you see why?) … Can you now draw the conclusions yourself? Stefano

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Stefano Baroni, Trieste -- http://stefano.baroni.me

> On 18 Dec 2024, at 03:56, Toshiharu Higuchi via users <users at lists.quantum-espresso.org> wrote:
> 
> Dear QE Users
> I have a question about the difference between ILDOS and |psi|^2.
> When I calculated the ILDOS (plot_num=10) and |psi|^2 (plot_num =7) of a
> hydrogen atom, the patterns were different.
> In the case of |psi|^2, 1s orbital → spherical, 2p orbital → 2-lobes, and
> 3d orbital → 4-lobes were obtained.
> However, in the case of ILDOS, all patterns were spherical.
> According to the literature, ILDOS can be calculated from |psi|^2 and
> Dirac's delta function.
> Even if |psi|^2 is a pattern other than spherical, ILDOS will be spherical.
> I don't understand the reason for this.
> Please tell me,
> (1) In Quantum-ESPRESSO, are ILDOS and |psi|^2 calculated in separate
> processes? Or is |psi|^2 calculated first and then ILDOS is calculated using
> this value?
> (2) Does Dirac's delta function have any effect?
> 
> Best regards,
> Toshiharu Higuchi
> 
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