From heat capacity data one can calculate a set of energy moments for any s
ystem. Using the maximum-entropy method, these energy moments can be used t
o construct an approximate energy probability distribution which, in turn,
can be used to calculate the density of states as a function of energy. The
density of states is a temperature independent function from which the fre
e energy, internal energy, entropy, and heat capacity for the system can be
obtained plus the energy probability distribution and its potential at any
temperature. We compare the behavior of the density of states for various
substances in a single phase and as one goes through different types of pha
se transition. (C) 2000 American Institute of Physics. [S0021-9606(00)50146
-9].