文摘
Photoionization of the iodine atom following methyl iodide A-band photodissociation was studied over thewavelength range of 245.5-261.6 nm by photoelectron imaging technique. Final state-specific speed andangular distributions of the photoelectron were recorded. Two types of the photoelectron resulted from ionizingthe I atom from the photodissociation of CH3I were identified: (a) (2 + 1) REMPI of the ground state Iatom, and (b) two-photon excitation of spin-orbit excited I(2P1/2) to autoionizing resonances converging tothe 3P1 state of I+. In addition, some weaker signals were attributed to one-photon ionization of I atomsproduced in some higher excited states from multiphoton ionization of CH3I followed by dissociation. Analysisof relative branching ratios to different levels of I+ (in case a) revealed that the final ion level distributionsare generally dominated by the preservation of the ion-core configuration of the intermediate resonant state.A qualitative interpretation of the electron angular distribution from an autoionization process is also given.