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Eigenvalues and density of states

  1. Mar 15, 2010 #1
    Hi guys

    I have an analytical expression f(x) for my density of states, and I have plottet this. Now, I also have a complete list of my Hamiltonians eigenvalues.

    When I make a histogram of these eigenvalues, I thought that I should get an exact (non-continuous) copy of my plot of f(x). They have the same form, but they are not to scale, i.e. f(x) has a maximum at ~100, while the histogram has a maximum at ~60.

    Is there an error somewhere, or am I wrong to expect that they should be "exact" copies?
  2. jcsd
  3. Mar 15, 2010 #2
    I am not sure whether i am correct!
    some scale factor for eigenvaues or for DOS?
    Also check with units of y-axis (i often get these errors when i convert meV to cm-1)
    or your data is convoluted already?
    Last edited: Mar 15, 2010
  4. Mar 15, 2010 #3
    The units are the same (I have checked).

    So you believe they should be the same?
  5. Mar 19, 2010 #4
    The units of a numerical histogram depend on the bin size chosen. Are you remembering to divide by the width of the bin?
  6. Mar 20, 2010 #5
    Isn't a histogram unit-less?
    Last edited: Mar 20, 2010
  7. Mar 20, 2010 #6
    Yes, a histogram is unitless. That's why you need to divide by the bin size to get it in units of 1/energy (or 1/energy/volume, if that's what you're dealing with).
  8. Mar 21, 2010 #7
    I see. Thanks - I'll play around with it to see if it works. Thanks.
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