X-ray absorption resonances near L2,3-edges from real-time propagation of the Dirac-Kohn-Sham density matrix.

The solution of the Liouville-von Neumann equation in the relativistic Dirac-Kohn-Sham density matrix formalism is presented and used to calculate X-ray absorption cross sections. Both dynamical relaxation effects and spin-orbit corrections are included, as demonstrated by calculations of the X-ray absorption of SF6 near the sulfur L2,3-edges. We also propose an analysis facilitating the interpretation of spectral transitions from real-time simulations, and a selective perturbation that eliminates nonphysical excitations that are artifacts of the finite basis representation.