We present exact quantum mechanical bound-state calculations for HCP using an ab initio potential energy surface. The main result is the existence of two distinct families of bending states : one with normal-mode-type behavior and wave functions confined to small bending angles and the other one sampling the isomerization path all the way from H-CP to CP-H. Stable periodic orbits provide a clear-cut assignment. Possible relations to recent spectroscopic observations are discussed.