  The chiral phase transition of QCD is analyzed in a model combining random
matrix elements of the Dirac operator with specially chosen non-random ones.
The special form of the latter is motivated by the assumption that the
fermionic quasi-zero modes associated with instanton and anti-instanton
configurations determine the chiral properties of QCD. Our results show that
the degree of correlation between these modes plays the decisive role. To
reduce the value of the chiral condensate by more than a factor of 2 about 95
percent of the instantons and anti-instantons must form so-called molecules.
This conclusion agrees with numerical results of the Stony Brook group.
