POLARIZATION EFFECTS IN MOLECULAR X-RAY FLUORESCENCE

Highly polarized x-ray fluorescence has been observed following K-shell excitation of several Cl-containing molecules. Monochromatic synchrotron radiation (SR) with a high degree of linear polarization was used to resonantly excite Cl 1s electrons in CH3Cl, and the three Freons, CF3Cl, CF,Cl2, and CF3Cl. The subsequent Cl Kβ fluorescence was found to be strongly linearly polarized. The direction of polarization of the Kβ fluorescence is determined in part by the symmetry of the valence-orbital electron involved in the fluorescence decay which fills the Cl 1s hole. Our results illustrate that the core-level resonance lifetimes are short enough to preclude substantial disorientation of the molecule prior to fluorescence decay. Measurements of this type may prove to be a sensitive probe of orbital symmetry in more complicated molecular systems, condensed matter, and adsorbates