Soft-wall models in AdS/QCD generally have dilaton and scalar fields that
vary with the fifth-dimension coordinate. These fields can be parameterized to
yield hadron mass spectra with linear radial trajectories and to incorporate
spontaneous breaking of chiral symmetry. We show how to construct scalar
potentials which lead to such solutions.Comment: 21 pages. Version 3 matches that accepted for publication. Typos have
been corrected and references added. Substantial discussion has been added in
order to clarify our approach and the issue of the dilaton mass in Sec. 4.
Central results and conclusions remain unchanged