The dynamics here differ considerably from those seen in the cryo-SEVI study of the F + CH3OH reaction despite remarkably similar neutral reactive surfaces. In particular, the simple low frequency progressions observed in that system within each vibrationally adiabatic manifold, which were assigned to the excitation in the CH3O-HF translation dissociation coordinate, are replaced by less regular spectral patterns. These differences arise in part because there is a larger geometry change upon photodetachment for FNH3ˉ. For example, in addition to excitation in the dissociation coordinate, there is ample excitation in the out-ofplane modes in the PC complex, resulting from the NH3 pyramidal-to-planar transition discussed above. In this respect, this system bears some similarities with the F + H2O system, for which high-level calculations have determined the involvement of the HO-HF bending mode in the dynamics of this system.