title: Imaging the stereodynamics of methyl iodide photodissociation in the second absorption band: fragment polarization and the interplay between direct and predissociation.
abstract: The stereochemistry of methyl iodide photodissociation in the onset of the second absorption B-band has been studied using slice imaging of the CH3(ν = 0) and I*((2)P1/2) photoproducts. The stereodynamical data have been crucial to disentangle the photochemistry of methyl iodide in terms of the competition between direct dissociation and electronic predissociation. The origin of the B-band has been established with high accuracy at 201.11 ± 0.12 nm and a depolarization factor due to parent molecule rotation during predissociation has been found to be 0.29 ± 0.06. Analysis of the semiclassical Dixon's bipolar moments extracted from the CH3(ν = 0) sliced images indicates that direct excitation to the A-band (3)A1 repulsive state in the vicinity of the origin of the B-band is remarkably enhanced by vibrational coupling between the electronic states involved at the conical intersection through in-plane vibrational motion of the molecule.
authors.affiliation: Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain. lbanares@ucm.es.
authors.forename: Marta G
authors.initials: MG
authors.lastname: González
authors.forename: Javier D
authors.initials: JD
authors.lastname: Rodríguez
authors.forename: Luis
authors.initials: L
authors.lastname: Rubio-Lago
authors.forename: Luis
authors.initials: L
authors.lastname: Bañares