Executive summary: It's energy per *quadratic* degree
of freedom.
On 02/25/2016 10:32 AM, Carl Mungan wrote:
So equipartition doesn’t apply?
There are a lot of misconceptions about equipartition.
The explanations you see in introductory books are often
grossly incorrect.
For starters, ask your students why a particle in a
parabolic potential (i.e. a harmonic oscillator) has
both KE and PE contributions to its heat capacity,
whereas a particle in a square-well potential (i.e.
a particle in a box) has only KE.
It's the same particle in both cases, but the two heat
capacities are markedly different.
Next question: What happens if we split the difference,
i.e. if we have a container with slightly rounded corners
and slightly sloping sides, so that it is not quite as
curvy as a parabola, yet not quite as square as a box?
This is directly relevant to part of the phase-change
question, because even though the particles are the same
in the gas as in the solid, their PE environment is quite
different.