THE RESONANCE ENHANCED (2+1) MULTIPHOTON IONIZATION SPECTRUM OF I-2

The resonance enhanced (2+1) multiphoton ionization spectrum Of 12 has been recorded in the region 48000-75300 cm-1 using both linearly and circularly polarized light. Rydberg states (ns) up to n=11 based on the [3/2]g ion core and up to n=8 on the [1/2]g core have been observed, together with three 5d states based on each core. Of these, twelve states have been observed for the first time and six other states have been reassigned. Assignments have been made by comparing the observed molecular quantum defects with those of atomic iodine, by using band contour analysis and by measurement of polarization ratios. Polarization ratios which are widely different from those expected have been observed for some systems.