Experimental determination of the potential energy curves of the I(3/2u) and I(3/2g) states of Kr-2(+)

The I(3/2u) and I(3/2g) states of Kr-2(+) have been investigated by pulsed- field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy following. (2 + 1') resonance-enhanced multiphoton excitation via the 0(g)( +) Rydberg state located below the Kr* ([4p](5) 5p [1/2](0)) + Kr(S-1(0)) d issociation limit of Kr-2. From the positions of a large number of vibratio nal bands in the spectra of the Kr-84(2) and Kr-84-Kr-86 isotopomers, the a diabatic ionization potentials (IP(I(3/2u)) = 112 672.4 +/- 0.8 cm(-1), IP( I(3/2g)) = 111 395.0 +/- 1.4 cm(-1)), the dissociation energies (D-0(+)(I(3 /2u)) = 368.8 +/- 2.0 cm(-1), D-0(+) (I(3/2g)) = 1646.2 +/- 2.3 cm(-1)) and vibrational constants for both ionic states have been determined. Potentia l energy curves have been extracted which perfectly reproduce all experimen tal observations and are accurate over a wide range of energies and internu clear distances. The equilibrium internuclear distances (R-e(+)(I(3/2u)) = 4.11 +/- 0.04 Angstrom, R-e(+)(I(3/2g)) = 3.35 +/- 0.10 Angstrom) have been derived by comparing the intensity distribution in the PFI-ZEKE photoelect ron spectra to calculated Franck-Condon factors. The dissociation energy of the I(3/2g) state and the equilibrium internuclear distance of the I(3/2u) state differ markedly from previously reported values.