About wavefunctions of Hydrogen atom

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The discussion centers on the confusion regarding the wavefunctions of the hydrogen atom, specifically the 2p_x and 2p_y functions, which are incorrectly listed as having quantum number m = 1 and -1 on a referenced webpage. These functions are actually linear combinations of the m = 1 and -1 states, leading to equal probabilities for measuring L_z. The participants clarify that while wavefunctions are generally complex, real wavefunctions can occur, particularly in bound states. The p_x and p_y functions are noted for their lobes along the x and y axes, similar to the p_z function along the z axis. The conversation also touches on the challenges of typing mathematical equations in the forum.
zhangpujumbo
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Every one knows that wavefunctions are generally complex functions described by three quantum numbers n, l and m, and the number m is included in the form exp(i*m*fai). But here in the following webpage they are all real functions, I'm confused:confused: . Can anyone help me?

Thank u in advance!
 
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Uh, what web page? :confused:
 
That page makes a mistake in listing (for example) the 2p_x and 2p_y wave functions as having m = 1 and -1. They are actually linear combinations of the functions with m = 1 and -1. Recall that

\cos \phi = \frac{e^{i \phi} + e^{-i \phi}}{2}

\sin \phi = \frac{e^{i \phi} - e^{-i \phi}}{2i}

If you measure L_z for either of these functions, you get + \hbar half the time, and - \hbar half the time, randomly.

The p_x and p_y functions are convenient for some purposes because they have lobes along the x and y axes, just like the p_z (m = 0) function has lobes along the z axis.
 
Wave functions can be real; typically this is the case for bound states. (Strictly speaking this holds for the radial function.) Think about harmonic oscillator wave functions -- they are real. Pretty standard stuff.
Regards,
Reilly Atkinson
 
jtbell said:
That page makes a mistake in listing (for example) the 2p_x and 2p_y wave functions as having m = 1 and -1. They are actually linear combinations of the functions with m = 1 and -1. Recall that

\cos \phi = \frac{e^{i \phi} + e^{-i \phi}}{2}

\sin \phi = \frac{e^{i \phi} - e^{-i \phi}}{2i}

If you measure L_z for either of these functions, you get + \hbar half the time, and - \hbar half the time, randomly.

Yes.

jtbell said:
The p_x and p_y functions are convenient for some purposes because they have lobes along the x and y axes, just like the p_z (m = 0) function has lobes along the z axis.

In Cartesean coordinates it's clearer:

p_z\ \ \propto\ \ \cos{\theta}\ =\ \frac{z}{r}

p_x\ \ \propto\ \ \sin{\theta}\cos{\phi}\ =\ \frac{x}{r}

p_y\ \ \propto\ \ \sin{\theta}\sin{\phi}\ =\ \frac{y}{r}

They are all the same.Regards, Hans
 
Last edited:
jtbell said:
That page makes a mistake in listing (for example) the 2p_x and 2p_y wave functions as having m = 1 and -1. They are actually linear combinations of the functions with m = 1 and -1. Recall that

\cos \phi = \frac{e^{i \phi} + e^{-i \phi}}{2}

\sin \phi = \frac{e^{i \phi} - e^{-i \phi}}{2i}

If you measure L_z for either of these functions, you get + \hbar half the time, and - \hbar half the time, randomly.

The p_x and p_y functions are convenient for some purposes because they have lobes along the x and y axes, just like the p_z (m = 0) function has lobes along the z axis.

Yes, I agree with your opinion very much!:approve:

There must be something wrong.

Thanks a lot:smile:
 
reilly said:
Wave functions can be real; typically this is the case for bound states. (Strictly speaking this holds for the radial function.) Think about harmonic oscillator wave functions -- they are real. Pretty standard stuff.
Regards,
Reilly Atkinson

I don't mean all wavefunctions must be complex.

But thank u all the same!
 
Hans de Vries said:
In Cartesean coordinates it's clearer:

p_z\ \ \propto\ \ \cos{\theta}\ =\ \frac{z}{r}

p_x\ \ \propto\ \ \sin{\theta}\cos{\phi}\ =\ \frac{x}{r}

p_y\ \ \propto\ \ \sin{\theta}\sin{\phi}\ =\ \frac{y}{r}

en, it's clearer.
 
  • #10
I don't know how to type mathematical equations here, it's too inconvenient.:cry:

How do you do that?
 
  • #12
jtbell said:

It seems that all the equations are copied piece by piece, then typying equations will be too laborious a task

Is there a shortcut?
 
  • #13
Not really. But LaTex is easy once you get past the initial shock.
 
  • #14
inha said:
Not really. But LaTex is easy once you get past the initial shock.

I think a compact software like mathtype will help greatly.
 

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