Dynamic screening in L_2,3-shell transition metal x-ray absorption
  Calculations of L-shell x-ray absorption in transition metals are shown to be sensitive to screening, both of the x-ray field and the photoelectron-core hole interaction. This screening is calculated using a generalization of the time dependent local density approximation and a projection onto a local atomic basis. The approach yields renormalized dipole-matrix elements which account for the observed deviations of the L_3/L_2 branching ratio from the 2:1 value of independent electron theory. 
A. L. Ankudinov, A. I. Nesvizhskii and J. J. Rehr (U. Washington)