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Homework Help: If a crystal has distinguishable sites

  1. Nov 16, 2013 #1
    compare the number of microstates for crystals consisting of a mixture of A atoms and B atoms if the crystals have 4, 8 and 16 distinguishable sites

    the question is ambiguous in that it simply states crystals, so im assuming its the same as given examples and is 2 crystals AAAA and BBBB.

    i dont want a direct answer as its course work, but my questions are:

    1) for the most probable macrostate i understand that it would be the most disordered, but am i correct in assuming that "a site" may be considered as an atom in the disorder???

    i.e. AABS, BBSA, SAAB etc etc would be the most likely macrostates? where S (an empty site) can be considered in the disorder?

    2) also, for a single crystal, i.e. 4 sites, since the sites are distinguishable, does that make the atoms in the sites distinguishable? I'm assuming yes, therefore you would need to consider that AAAA in distinguishable sites must be considered A1A2A3A4, because the site plus the atom would be distinguishable by the distinguishability of the site. that make sense?

    thanks for any pointers in the right direction?
  2. jcsd
  3. Nov 16, 2013 #2
    "In modeling the solid state, one typically assumes that the atoms are confined to lattice sites, and that each site is occupied at most once.. In this case, the position in the lattice is a distinguishable label, which makes all atoms distinguishable."

    so thats the second question answered.

    just need to know if an empty site can be considered as an atom in determining the most probable macrostates
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