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Topic: How to show spherical symmetry?  (Read 9300 times)

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Offline Sophia7X

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How to show spherical symmetry?
« on: June 24, 2012, 09:56:24 PM »
Show that the electron distribution is spherically symmetrical for an atom with an electron that occupies each of the 3 p orbitals of a given shell.




 I know that I'm supposed to do something with the angular wavefunctions, but what?

Ypx(θ,Φ) = (3/4π)0.5sinθcosΦ
Ypy(θ,Φ) = (3/4π)0.5sinθsinΦ
Ypz(θ,Φ) = (3/4π)0.5cosθ

Also, I know that spherically symmetrical = independent of θ and Φ

I would show my attempt at this problem... if I knew how to. :P Could someone point me in the right direction?
Entropy happens.

Offline Jorriss

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Re: How to show spherical symmetry?
« Reply #1 on: June 24, 2012, 10:09:53 PM »
Show that the electron distribution is spherically symmetrical for an atom with an electron that occupies each of the 3 p orbitals of a given shell.




 I know that I'm supposed to do something with the angular wavefunctions, but what?

Ypx(θ,Φ) = (3/4π)0.5sinθcosΦ
Ypy(θ,Φ) = (3/4π)0.5sinθsinΦ
Ypz(θ,Φ) = (3/4π)0.5cosθ

Also, I know that spherically symmetrical = independent of θ and Φ

I would show my attempt at this problem... if I knew how to. :P Could someone point me in the right direction?
In quantum mechanics, the probability of measuring a particle between points a and b goes like the wave function squared.

So, Y31m(θ,Φ)^2 goes like the probability. To show it is independent of theta or phi, sum over m and show Y311(θ,Φ)^2+Y310(θ,Φ)^2+Y31-1(θ,Φ)^2 has no angular dependence.

That's impressive for High school chemistry.

Offline Sophia7X

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Re: How to show spherical symmetry?
« Reply #2 on: June 24, 2012, 10:43:15 PM »
Yeah, not exactly high school chemistry we're learning in school, lol. I'm just self-studying/furthering my chem studies over the summer.

Quote
In quantum mechanics, the probability of measuring a particle between points a and b goes like the wave function squared.
Thanks for reminding me, I keep thinking that probability and wavefunction are the same thing!

OK, here's my work so far after squaring everything...

(3/4π)sin2θcos2Φ + (3/4π)sin2θsin2Φ + (3/4π)cos2θ

(3/4π)(sin2θcos2Φ + sin2θsin2Φ + cos2θ)

I don't know what to do next


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Offline Sophia7X

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Re: How to show spherical symmetry?
« Reply #3 on: June 24, 2012, 10:47:26 PM »
Ohh, never mind
It can be factored a little bit more.
And simplified using trig identities, which I never thought I would ever apply to anything else but trig.

(3/4π)(sin2θ(cos2Φ + sin2Φ) + cos2θ)
(3/4π)(sin2θ(1)+ cos2θ)
=(3/4π)

so the distribution is independent of θ and Φ and spherically symmetrical

Thanks for your help :)


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Offline Jorriss

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Re: How to show spherical symmetry?
« Reply #4 on: June 25, 2012, 12:10:03 AM »
There you go.

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