Density functional-time-dependent local density approximation calculations of autoionization resonances in noble gases

Absolute photoionization cross section profiles and asymmetry parameters of Ne, Ar and Kr have been calculated at the time-dependent local density approximation level. We employed a very accurate B-spline finite basis set and the modified Sternheimer approach, which is a first-order perturbative scheme particularly suited to finite basis set calculations. The gradient-dependent van Leeuwen and Baerends (VLB) exchange-correlation potential has been used, since it has the correct Coulombic behaviour at large distances which is a necessary condition for the existence of the Rydberg states. A simple modification of the boundary conditions considerably improves the number of terms of the Rydberg series. The resonance parameters obtained by fitting the calculated Fano profiles with a suitable analytic expression are compared with the experimental parameters.