ORIENTATION AND ALIGNMENT OF P-2(3/2) FRAGMENTS FOLLOWING PHOTODISSOCIATION OF HETEROATOMIC MOLECULES

We theoretically treat the effect of orientation and alignment of the atomic photofragments produced in the photodissociation of diatomic molecules. The theory describes all possible nonadiabatic interactions in the decaying molecules as well as rotation of the molecular axis and coherent effects. The production Of P-2(3/2) fragments, when the interaction between the atoms at large internuclear distance is of the quadrupole-quadrupole type, is discussed in detail. We discuss the results of two different types of experiments: (a) polarization of the fluorescence of excited Na(3 P-2(3/2)) atoms produced in the photodissociation of NaI and (b) orientation and alignment of metastable Tl (6 P-2(3/2))) atoms produced in the photodissociation of TlBr at 266 nm. The theory explains for (a) the results of the experiments that failed to detect a linear polarized Na fluorescence and for (b) the observed large orientation and alignment effects. We also discuss the orientation effect in case (a) if one uses circularly polarized dissociation light.