Statistical Physics 275
Solution:
p = - (g) , where F is the free energy, F = E - TS. When
T
T = 0 K, F = E, and
p=-(g) T.
2
Using pV = -El we have
3
or
p=-(g)T=-[-.-(fpV)]T=-;[V(g)T+P] a ,
5
1 av 3
Hence K. = --
(-)
= - (T = 0 K).
ap T 5P
At T = 0 K,
h2k2
d3k-
2E 2 V
3V 3V (2~)~ /,,,, 2m
p= - = -.2.-
we obtain
For an ideal gas, the energy of a particle is
h2 k2
2m
&(k) = -.
Thus
h2 k;
2m
&F=-.
Therefore,
2
5
p= -n.&F, (T= 0 K) ,
and
3
K.= -. (T=OK)
2n&F