AUGER-ELECTRON SPECTROSCOPY OF MOLECULES - CIRCULAR-DICHROISM FOLLOWING PHOTOABSORPTION IN ROTATING LINEAR-MOLECULES

In this paper we show the existence of circular dichroism in both inte grated as well as differential Auger currents produced in the decay of a vacancy created by the absorption of a circularly polarized photon in a gaseous linear molecule. It arises due to a rotational orientatio n of the photoexcited molecule or excited photoion. Although Auger ele ctrons in such experiments should necessarily be observed along with t heir spins, neither the spin-orbit nor spin-rotation interactions, how ever, need to be taken into account. Circumstances when dichroic effec ts in such experiments are independent of photoabsorption and/or Auger -emission dynamics have also been clearly brought out by us. We have c alculated the magnitude of the circular dichroism for certain realisti c cases and have shown it to be of the order of magnitude of the total Auger intensity. It is proposed that circular dichroism in Auger spec troscopy provides a direct and simple method to probe rotational orien tation produced by the absorption of circularly polarized light in gas eous linear molecules and to calibrate the degree of circular polariza tion of electromagnetic radiations over a wide range of photon energy.