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Polymer Question

  1. Jul 21, 2008 #1

    bb1

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    I'm trying to calculate the structure factor for a polymer melt: S(q)=[tex]\sum_{k}[/tex][tex]\sum_{j}[/tex][tex]\epsilon^{i*<q>*<r_{kj}>}[/tex], but I don't know how to deal with the imaginary exponent...(the rest of the variable don't really matter, because I'm confused about how to deal with the exponent, but q is the scattering vector, and r[tex]_{kj}[/tex] is the distance between vectors k and j) my first thought was to multiply by the complex conjugate, but doesn't that just get rid of the exponential altogether, leaving nothing for you to add? I don't understand how I can get any data if I multiply by the complex conjugate. Anyone have any suggestions?
     
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  3. Jul 21, 2008 #2

    Mapes

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    Use http://en.wikipedia.org/wiki/Euler%27s_formula" [Broken] and consider only the real part of the trig side (i.e., the cosine). The exponential form makes some calculations easier.
     
    Last edited by a moderator: May 3, 2017
  4. Jul 21, 2008 #3

    bb1

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    Thanks for responding!
    I considered that, but it doesn't seem correct to just throw out the complex part...is there something I'm missing?
     
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