  Using the methods of moving frames and exterior differential systems, we show
that there exist Hopf hypersurfaces in complex hyperbolic space CH^2 with any
specified value of the Hopf principal curvature less than or equal to the
corresponding value for the horosphere. We give a construction for all such
hypersurfaces in terms of Weierstrass-type data, and also obtain a
classification of pseudo-Einstein hypersurfaces in CH^2.
