Two-dimensional photoelectron imaging of state-selected iodine atom by (2+1) resonance-enhanced multiphoton ionization

The state-selective photoelectron imaging technique is applied to investigate the angular distribution of ejected electrons and the electronic state of the atomic ion produced by (2+1) resonance-enhanced multiphoton ionization of iodine atom in the photolysis of CH3I. Strong anisotropic distribution behaviors have been depicted on two electron images observed, one via the two-photon resonance 2D520 state from ground state iodine and, another via 4D520 from spin-orbit excited iodine. The configuration of core electrons is preserved in the ionization from the 2D520 intermediate state, while the ionization from the 4D120 state shows two distinct ionization paths, a preserved and a non-preserved path of core electrons.