Vibrational dynamics of the I-3 radical: A semiempirical potential surface, and semiclassical calculation of the anion photoelectron spectrum

The semiempirical diatomics in molecules (DIM) approach is used to model the potential surface for ground-state vibration of a linear I-3 molecule. We use this system to explore semiclassical methods for treating quantal nuclear vibrations by computing the photoelectron spectrum of I-3(-) which produces vibrationally excited I-3 We compare semiclassical results with full quantum calculations and experimental results recently reported by Neumark and co-workers.