1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Expectation values of the electron.

  1. Feb 5, 2009 #1
    1. The problem statement, all variables and given/known data

    The expectation value <r> of the electron-nucleus separation distance 'r' is:

    <r> = ʃ r |ψ|² dV.

    (a) Determine <r> for the 1, 0, 0 state of hydrogen.





    3. The attempt at a solution

    Right, I've obtained the value for ψ = (1/πa³)^1/2 exp(-r/a)

    I then replace dv by 4πr² dr.

    I then put all of that in the equation above and try to integrate but I cant seem to go any further from here. Any help?

    Thanks very much.
     
  2. jcsd
  3. Feb 5, 2009 #2

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Are you having trouble with the integral? Remember how to integrate by parts?
     
  4. Feb 5, 2009 #3
    I think it might be the integral. The problem is, I have an exponential term in the integral which I can't solve by parts? if so how?
     
  5. Feb 5, 2009 #4

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    How are you trying to integrate, and what's the problem? Show us what you are doing.
     
  6. Feb 5, 2009 #5
    Your integral should be of the form:

    u dv = exp(-2r/a) r^3 dr

    All you have to do is assign u and v. Hint: you will have to integrate by parts several times.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Expectation values of the electron.
  1. Expectation Value (Replies: 1)

  2. Expectation values (Replies: 1)

  3. Expectation values (Replies: 4)

Loading...