Abstract

The polarization of fluorescence from excited photofragments contains valuable information on the decomposition dynamics following excitation and fragmentation. Specifically, it is possible to determine the anisotropy (alignment and orientation of population within the fragments) characterizing the fragmentation (ionization and/or dissociation) processes.¹ We have measured the polarization of ${\text{O}}_2^{+}$ fluorescence as a function of input photon energy to determine the alignment in the $b_4{\Sigma }_g^{-}$ and A²∏_u states. Monochromatized synchrotron radiation, from the NBS-Gaithersburg Synchrotron Radiation Facility (SURF II), was employed to photoionize an effusive beam of O₂ into the A and b states of ${\text{O}}_2^{+}$ while the polarization of the subsequent A → X and b → a fluorescence was monitored. The results of our measurements are presented and contrasted with recent photoelectron angular distribution measurements² on O₂ in the same energy region.

© 1986 Optical Society of America