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Homework Help: What's the meaning of the Cartesian coordinates of the atom?

  1. Jan 10, 2006 #1
    How to get the Cartesian coordinates of an atom?

    Dear friends,
    Such a question confused me when reading!:confused:
    "xi,yi and zi are the Cartesian coordinates of the ith atom"
    How to get the coordinate of an atom? For example: carbon, oxygen?
    I think the atom is only a dot! What's the way to indicate it with Cartesian coordinate?
    Lend a hand,please!
    Thank you!!
    Last edited: Jan 10, 2006
  2. jcsd
  3. Jan 10, 2006 #2


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    Homework Helper

    They're telling you the coordinate of the atom's center-of-mass
    (we always describe the location of an object by its c.o.m. location!).
    The C atom is at ( x_c , y_c , z_c ) ; the O atom is at ( x_o , y_o , z_o ) .
  4. Jan 10, 2006 #3
    Thank you for your help.
    But I need the specific numerical value for calculating.
    How to get it?
  5. Jan 10, 2006 #4


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    Well, if they're not given in the problem, choose:
    a) the text might list some inter-atom spacings in the chapter
    b) you're supposed to keep them as variables (x,y,z)

    What are you supposed to be calculating / computing ?
  6. Jan 10, 2006 #5
    Until now, I didn't find any text about inter-atom spacings
    To calculate moments of inertia.
    I only want to get the value of several atoms.
    Last edited: Jan 10, 2006
  7. Jan 11, 2006 #6
    Actually, I'm not sure whether I need calculate the Cartesian coordinates or not. But I hope not. Because my only intention is to get the value of carbon, oxygen and so on.
  8. Jan 11, 2006 #7


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    Of what ??? ( For instance, a carbon dioxide molecule about an axis perpendicular to the molecular axis ?) Please write down the given question completely. You have not provided enough information.
  9. Jan 11, 2006 #8
    are you trying to say something like:
    how many atoms does a carbon or oxygen have????
  10. Jan 28, 2006 #9
    To calulate the moment of inertia using J.O. Hirshfelder's method
    Do you know?
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