Photodissociation of O[sub 2] in the Herzberg continuum. II. Calculation of fragment polarization and angular distribution.

Parallel and perpendicular components of the Herzberg I, II, and III transitions contribute to the photodissociation of O[sub 2] in the Herzberg continuum. The photodissociation dynamics determines the O([sup 3]P[sub j]), j=0,1, and 2 atomic fine-structure branching ratios and angular distributions, which were determined in ion imaging experiments at λ=236, 226, and 204 nm by Buijsse et al. [J. Chem. Phys. 108, 7229 (1998)]. In the preceding paper we presented potential energy curves for all eight ungerade O[sub 2] states that correlate with the O([sup 3]P)+O([sup 3]P) dissociation limit, and the R-dependent spin–orbit and the nonadiabatic radial derivative couplings between these states. Here, we employ these potentials and couplings in a semiclassical calculation of the fine-structure branching ratios, atomic polarizations, and fine-structure resolved anisotropy parameters. We discuss the adiabaticity of the dissociation by comparing the results with adiabatic and diabatic models. The O([sup 3]P[sub j]) 2+1 REMPI detection scheme used in the experiment is sensitive to the polarization of the atomic fragments. We predict an important effect of the polarization on the anisotropy of the j=1 and j=2 ion images at low energies (λ>236 nm). The agreement between the semiclassical calculations and experiment is reasonable, possible explanations for the remaining differences are discussed. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]