Normal mode and isomerization bending states in HCP: Periodic orbit assignment and spectroscopic signature.

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. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]