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Which theory, Law or equation I should use to simulate molecules motion while heating

  1. Feb 22, 2010 #1
    hi
    before anything don't blame me much cause I'm chemical Eng & don't know physics much!
    I'm about to run a computer simulation which is strongly related to physics so I need your help.

    I need to simulate the motion of molecules when I heat them up likely a heavy liquid
    perhaps some equation like Einstein-Stokes but that one was for particles in a fluid.
    or maybe Schrödinger equation?
    I'm totally confused can you guys help me find out?
     
  2. jcsd
  3. Feb 22, 2010 #2

    SpectraCat

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    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    Note to admins: This thread should probably be moved to a more appropriate section

    It is unlikely that you need to use Schrodinger equation, or consider the quantum properties of the molecules ... at least not in the initial treatment. Check out the book, "Computer Simulations of Liquids" by Allen and Tildesley for a good review of the relevant techniques for classical simulations. In the meantime, can you give a little more information about your problem? For example, how do you want to represent your molecules? Will hard spheres work? Do they need to have shapes? Do you need to include an interaction potential between the molecules? Are there more than one kind of molecule in the fluid?
     
  4. Feb 22, 2010 #3
    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    what is important for me is that the simulation should show the effect of heating on molecules motion well at least at a moderate accuracy the rest doesn't really matter much in this simulation.
    I men for example if the hard sphere works better for liquid molecules motion on heating then that one is better.
    and thanks for the book will try that
     
  5. Feb 23, 2010 #4
    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    plz some one help me.
    at least name some of equations used to describe molecules motion.
     
  6. Feb 23, 2010 #5

    turin

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    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    That still doesn't tell us much. Regarding the quantum mechanical aspect, you may want to consider how the different modes are excited (e.g. compare the specific heat of a monatomic and diatomic gas).
     
  7. Feb 23, 2010 #6

    SpectraCat

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    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    How about Newton's equations? Every particle will feel a force that is given by the gradient of the potential. Every particle will start out with a position and a momentum. Now, propagate the positions of all the molecules in time. That's all you need for the simulation. The devil is in the details however, and the functions you use to represent the intermolecular potentials are crucial.

    What this should get across to you is that this is far from being a trivial problem ... molecular dynamics is *complicated* to simulate accurately using a computer program. It is possible that it is reasonable to make some simplifying assumptions in your application, but without more detail, it is very hard to guess what those assumptions might be.

    Is part of this project writing the code yourself? In that case, the book I mentioned will be incredibly helpful.
     
  8. Feb 24, 2010 #7
    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    I just found some applications for molecular dynamics simulation but they are for bio stuff.
    I want to study lorentz force on their motion.
    and yup If I have to I'll code the program by myself
    and of course I don't want to study that motion on a super computer.
    so I'll choose the simplest method or program if you know
     
  9. Feb 24, 2010 #8

    SpectraCat

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    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    Lorentz force? So these are *charged* molecules, and you are going to be applying a field to them? Are we talking about an ionic liquid here?
     
  10. Feb 25, 2010 #9
    Re: which theory, Law or equation I should use to simulate molecules motion while hea

    yup I'll have to use charged molecules and of course ions will be on my list.
    consider this all my molecules will be charged + or - I mean they all will be unique
     
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