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Why optically active molecules rotate light?

  1. Sep 29, 2012 #1
    Say, we have a solution of pure form of R-alanine. Say, the molecule has it's COOH group directed along positive y-axis and rotates the z-polarized light clockwise - the question is why the same molecule with it's COOH group in negative y direction won't do the opposite.
  2. jcsd
  3. Sep 29, 2012 #2


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    Consider a simpler example, a helix. How does a helix look like when you rotate it by 180 deg?
    An example of a chiral molecule with a helical structure are the helicenes:
  4. Sep 30, 2012 #3
    Fascinating :). Thank you for the reply, DrDu.
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