- #1

frankR

- 91

- 0

a) r = 0

b) r = r

_{b}

I confused how this probability function is used. What's the technique here?

Thanks

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter frankR
- Start date

- #1

frankR

- 91

- 0

a) r = 0

b) r = r

I confused how this probability function is used. What's the technique here?

Thanks

- #2

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

The wavefunction Ψ(r) should be in your book. You already stated the definition of the probability density (|Ψ|

- #3

frankR

- 91

- 0

Okay, what do I use for A, n, L and x?

If I evaluate x=0 I get 0. But the answer is non-zero.

If I evaluate x=0 I get 0. But the answer is non-zero.

- #4

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

Originally posted by frankR

Okay, what do I use for A, n, L and x?

Whoa: What are A, n, and L? Also, don't you mean r instead of x?

If I evaluate x=0 I get 0. But the answer is non-zero.

If you evaluate

- #5

frankR

- 91

- 0

|Ψ|

No radial coordinate.

- #6

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

Originally posted by frankR

Halliday gives:

(|Ψ|^{2}) = A^{2}Sin^{2}(n:pi:/L * x), n = 1, 2, 3,...

No radial coordinate.

That's the wavefunction for a particle in a box. It isn't applicable to the hydrogen atom. You need to look up that wavefunction, which will certainly have a radial coordinate.

- #7

frankR

- 91

- 0

Ψ(r) = 1/(sqrt[[pi]a

Square that and evaulate, or can I just evaluate and squre?

- #8

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

- #9

frankR

- 91

- 0

I get: 6.121e^9

- #10

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

And you got your answer how...?

- #11

frankR

- 91

- 0

Since a=5.29x10^-11m the answer should be very large.

This must not be the correct formula or something.

- #12

quantumdude

Staff Emeritus

Science Advisor

Gold Member

- 5,575

- 23

Originally posted by frankR

Since a=5.29x10^-11m the answer should be very large.

You should ask yourself:

It should be very large in what units?

You are working in meters, and the answer was given in inverse cubic nanometers.

- #13

frankR

- 91

- 0

HAHHAHA!

That's what happens when you do physics for 10 hours straight.

Edit: BTW, I've never seen that type of unit used before so my brain must have dismissed it.

That's what happens when you do physics for 10 hours straight.

Edit: BTW, I've never seen that type of unit used before so my brain must have dismissed it.

Last edited:

- #14

frankR

- 91

- 0

Oh BTW: Thanks for your help Tom.

Share:

- Last Post

- Replies
- 22

- Views
- 435

- Replies
- 1

- Views
- 323

- Last Post

- Replies
- 6

- Views
- 123

- Replies
- 4

- Views
- 518

- Replies
- 17

- Views
- 662

- Replies
- 6

- Views
- 392

- Replies
- 7

- Views
- 195

- Replies
- 5

- Views
- 376

- Last Post

- Replies
- 1

- Views
- 246

- Replies
- 9

- Views
- 340