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Solid State Heat capacity optical and acoustic

  1. Nov 20, 2011 #1
    1. The problem statement, all variables and given/known data

    A material has 104 atoms in its primitive cell with a speed of sound of 1500 m/s. It is well above the debye temperature. From Cv=3kb per atom, we calculate the volumetric heat capacity of 1.4*10^6 J m^-3 K^-1.

    What fraction of he heat capacity is in the acoustic branches?

    2. Relevant equations

    The thermal conductivity is also give but think its only relevant for the next part of the question

    3. The attempt at a solution

    Thought to use the high temp debye model of heat capacity to give acoustic, but that would give 100%.

    Not sure if it as something to do with the volumetric heat capacity

    Any direction would be helpful
    Last edited: Nov 20, 2011
  2. jcsd
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