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Homework Help: Lennard Jones Potential Equation: Repulsive and Attractive terms?

  1. Aug 9, 2009 #1
    http://www.ph.qmul.ac.uk/phy108/CM2008_week2_exercise1_solution.pdf [Broken]

    The L-J Potential Curve in question 2),

    V(r) = V(r) repulsive + V(r) attractive

    Is the ^12 term the repulsive term and ^6 is the attractive term?
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Aug 9, 2009 #2


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    Well, [itex]\textbf F=-\nabla V[/itex]....what sign does an attractive force have? Which term in the potential produces a force with that sign?
  4. Aug 9, 2009 #3


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    Alternatively, keeping in mind that the force acts in the direction of lower potential:

    Image a graph of 1/r12. Is that an attractive or repulsive potential?

    Do the same for a graph of -1/r6
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