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Dipole-dipole interaction

  1. Feb 5, 2005 #1
    Could anyone please provide (or start off) the proof of (2.4) of the following document?

    http://www-its.chem.uva.nl/research/complex_fluids/Teaching/LectureNotes%202004%20vdWaals%202.pdf [Broken]

    Many thanks
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Feb 6, 2005 #2
    The scalar potential from a electric dipole is given by
    [tex]\phi=\frac{\vec{p}\cdot \vec{r}}{4\pi \epsilon_0 r^3}[/tex]
    [tex]\vec{E}=-\bigtriangledown \phi[/tex]
    and with
    [tex]U=-\vec{p}\cdot \vec{E}[/tex]

    you'll get exactly Eq. (2.4)!
  4. Feb 8, 2005 #3
    I don't think I get the 3 in the numerator, nor the p dot p term.
  5. Feb 8, 2005 #4
    You don't think you get it OR you didn't get it?

    [tex]\partial_x (x^2+y^2+z^2)^{-3/2}=-\frac{3}{(x^2+y^2+z^2)^{5/2}}[/tex]

  6. Feb 9, 2005 #5
    Oh....I was working with spherical coordinates.
  7. Nov 17, 2009 #6
    There should not be a problem whether it is a sphere coordinate or not. Every two coordinates can transform into each other.
  8. Nov 17, 2009 #7

    Vanadium 50

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    It's been 4-1/2 years since he asked the question, I'm afraid,
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