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Debye temperature

  1. Aug 16, 2008 #1
    I guess is Debye temperature dependent on temperature? I.e TD(T)?
    Does anybody know a theoretical formula for temperature dependence of Debye temperature?:confused:
     
    Last edited: Aug 16, 2008
  2. jcsd
  3. Aug 16, 2008 #2

    Astronuc

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  4. Aug 16, 2008 #3
    Thanks, However, I know this references.
    My problem is:
    I have got specific temperature dependence C(T) for the solid compound.
    I can estimate Debye temperature from the fit, but it will be only one value for the whole range of temperatures.
    How can I estimate Debye temperature at specific temperature?
    How can t be estimated from material dependent variables? I know the formula for TD http://en.wikipedia.org/wiki/Debye_model but what should I use as N and V?
    If V stands for volume, what means N or rather how to calculate it?
    Could you give me an example? I mixed up :confused:
     
  5. Aug 16, 2008 #4

    Astronuc

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    In the Wikipedia article cited - http://en.wikipedia.org/wiki/Debye_model#Debye.27s_derivation - N is the number of atoms.

    If the atomic density is given by [itex]\rho[/itex]NA/A, where [itex]\rho[/itex] is the density, NA is Avogadro's number, A is the atomic mass.
     
    Last edited: Aug 16, 2008
  6. Aug 16, 2008 #5

    Gokul43201

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    Any temperature dependence in the Debye Temperature comes from temperature dependences in elastic constants (and due to thermal expansion). These changes are small: about 1 part in 1000 to 1000,000 per Kelvin.
     
  7. Aug 19, 2008 #6
    Thanks for both responses.
    I have still a problem with N/V (number per atoms in unit volume).
    I have got elementary cell volume V and mass weight of the molecule M.
    The cryst. group is P1-. I don't have density,
    How can I calculate N/V?
     
  8. Aug 19, 2008 #7

    Astronuc

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    What type of molecule, i.e. is this a mineral or alloy?

    For some basic lattices, there is usually a given number of atoms/cell and a unit cell volume based on the geometry and lattice parameters. It's a close estimate to get N/V, if one doesn't have mass density.
     
  9. Aug 19, 2008 #8
    My molecule is organic compound - benzene derivative, I visualised elementary cell but
    it seems complicated to calculate the number of atoms...
    I have got cell parameters.
     
  10. Aug 20, 2008 #9
    Where can I find a procedure for Debye model evaluation or tables of this integral value?
    I have found a reference to the tables by HARRISON but not available for me...
     
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