In this article, we investigate orthogonal polynomials associated with
complex Hermitean matrix ensembles using the combination of the metho
ds of Coulomb fluid (or potential theory), chain sequences, and Birkho
ff-Trjitzinsky theory, We give a general formula for the largest eigen
value of the N x N Jacobi matrices (which is equivalent to estimating
the largest zero of a sequence of orthogonal polynomials) and the two-
level correlation function for the alpha ensembles (alpha > 0) introdu
ced previously for alpha > 1, In the case of 0 < alpha < 1, we give a
natural representation for the weight function that is a special case
of the general Nevanlinna parametrization, We also discuss Hermitean m
atrix ensembles associated with general indeterminate moment problems.