Chitkara University, India
Title: Alignment of atomic inner shell vacancies-A detailed study
Biography: Ajay Sharma
Alignment is accounted in terms of alignment parameter A20, the fractional difference of the photo-ionization cross-sections of magnetic sub-states. The alignment of vacancies results in anisotropic distribution of x-rays originating from the filling of the vacancies as alignment is exhibited by directional correlation and polarization of characteristic X-rays and Auger electrons emitted on decay of the vacancies. Direct measurements of dependence of photo-effect on magnetic sub-states are not possible, but can be derived from the observed radioactive transitions or non-radioactive emissions. In the current work alignment studies are made for rare earth and high Z-elements using theoretical, empirical and experimental approaches. The theoretical value of alignment parameter A20 has been calculated by using the non-relativistic dipole approximation in a point Coulomb potential and analytical perturbation theory in a screened Coulomb potential. For empirical evaluations IGELCS interpolated experimental LXRF cross-section values are used along with radiative decay rates. The experimental measurements have been performed in XRF laboratories of Raja Ramanna Centre for advanced technology (RRCAT-India) using a three dimensional double reflection set-up. The comparison of alignment studies has been found almost similar via above methods and the alignment values at the L3 threshold energy >0.1were certainly higher (5-8%) than the earlier quoted experimental results of various groups.