Predissociation dynamics of the C 3Πg Rydberg state of molecular oxygen.

ABSTRACT

(2+1) resonance enhanced multiphoton ionization time-of-flight mass spectroscopy (TOF-MS) has been used to detect both the O((3)P) and O((1)D) fragments produced as a result of predissociation of the C (3)Πg (v = 0) and (v = 1) Rydberg states of O2. In particular, TOF profiles have been recorded at various fixed wavelengths within the two bands in order to investigate the differences in predissociation dynamics of intermediate levels with different values of |Ω| (=0, 1, 2 in this case). TOF profiles have been recorded in multiple geometries to determine both the translational anisotropy and angular momentum alignment of both photofragments as well as the O((3)P) spin-orbit branching ratios produced following a two-photon dissociation. The translational anisotropy is found to be dependent on the dissociation wavelength with the variations found to be consistent with rotational depolarization due to the long lifetime of the excited C state. All photofragments have been found to be aligned, with the relationship between the measured O((3)P) and O((1)D) alignment being found to be consistent with a diabatic model of the dissociation.