Spherical symmetri of eigenfunctions?

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Homework Help Overview

The discussion revolves around demonstrating the spherical symmetry of eigenfunctions associated with the hydrogen atom's first two n-shells. The original poster presents four specific eigenfunctions and seeks guidance on how to show that their superposition is spherically symmetric within each shell.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the concept of spherical symmetry, questioning whether it can be shown by evaluating the function's behavior under transformations of the angles and radius. They discuss specific cases of the eigenfunctions and their dependence on variables.

Discussion Status

Some participants have provided insights into specific eigenfunctions and their radial dependencies, suggesting that if a function depends solely on the radius, it may be considered spherically symmetric. Others are questioning the conditions under which symmetry can be established, particularly for functions that involve angular components.

Contextual Notes

Participants note the challenge of demonstrating spherical symmetry in a general sense and express uncertainty about the implications of certain transformations on the eigenfunctions. There is also a mention of potential confusion regarding the interpretation of terms in the fourth eigenfunction.

Azael
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I have been given these 4 eigenfunctions of the hydrogen atoms first 2 n-shells.

[tex]\psi_{100}(r, \theta, \phi )=\frac{1}{\sqrt{\pi a^3_0}}e^{-r/a_0}[/tex]

[tex]\psi_{200}(r, \theta, \phi )=\frac{1}{\sqrt{8\pi a^3_0}}(1-\frac{r}{2a_0})e^{-r/2a_0}[/tex]

[tex]\psi_{210}(r, \theta, \phi )=\frac{1}{4\sqrt{2\pi a^3_0}}(\frac{r}{a_0})e^{-r/2a_0} cos\theta[/tex]

[tex]\psi_{21\pm 1}(r, \theta, \phi )=\pm\frac{1}{8\sqrt{\pi a^3_0}}(\frac{r}{a_0})e^{-\frac{r}{2a_0}} sin\theta e^{\pm i\phi}[/tex]

Where [tex]a_0[/tex] is the Bohr radius.

I am suposed to show that the superposition
[tex]|\psi_{nlm}(r, \theta, \phi )|^2[/tex] is sphericaly symmetric within each shell.

Now what I don't know is how do I show spherical symmetri(not even generaly and not just in this particular case). Any hints?:confused:
 
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do I basically just show that the superposition has the same value in a arbitrary r and -r? and the same for [tex]\phi[/tex] and [tex]\theta[/tex]
 
I guess I should rephrase.

How do I show that any function is sphericaly symetric? Right now my brain has frozen even though I know it must be ridicilously simple.

Ignore the -r brainfart in the previous post btw.

What I mean is that should I show the function is the same if I hold r, theta constant and replace phi with -phi and then if I hold r and phi constant and replace theta with -theta?
 
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the first one
[tex]|\psi_{100}|^2 = \frac{1}{\pi a_0^3}e^{-\frac{2r}{a_0}}[/tex]
this is obviously sphericaly symmetric since it only depend on the radius. Its a sphere pure and simple. But is that proof enough?

The second one

[tex]|\psi_{200}|^2 = \frac{1}{8\pi a_0^3}[1-\frac{r}{2a_0}]^2 e^{-\frac{r}{a_0}}[/tex]

same as above? only radialy dependent=the function gest weaker in the radial direction, obviously spericaly symetric.

third one

[tex]|\psi_{210}|^2=\frac{r}{32\pi a^3_0}e^{-\frac{r}{a_0}} (cos\theta)^2[/tex]

Now this one. If I hold r constant and replace theta with -theta I get the same answere. So does that mean sphericaly symetric? Do I just have to say that to prove it?

In the fourth one at the end

The [tex]sin\theta e^{\pm i\phi}[/tex] should I read that as [tex]sin(\theta e^{\pm i\phi})[/tex] or [tex]sin(\theta) e^{\pm i\phi}[/tex] ??
 
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