Effects of the FEL Fluctuations on the 2s2p Li+ Auto-Ionization Lineshape

The photoionization of Lithium (Li+) via its doubly-excited state 2s2p 1P in intense free electron laser (FEL) radiation is studied. A recently developed perturbative statistical description of the atomic dynamics is used to calculate the ionization yield. It is observed that the FEL temporal fluctuations affect the lineshape significantly, strongly dependent on the product of the pulse’s coherence time with its intensity, ∼τcI0, which is a measure of the effect of the field in one correlation time. The weak-field long-pulse asymmetric resonant Fano-profile is broadened to resemble a Voight profile. As the intensity increases, the subsequent ionization of Li2+ takes over and causes further distortion of the lineshape for Li+.

ON TIME DEPENDENT DFT WITH SIC

We discuss an extension of time dependent density functional theory by a self-interaction correction (SIC). A strictly variational formulation is given taking care of the necessary constraints. A manageable and transparent propagation scheme using two sets of wave-functions is proposed and applied to laser excitation with subsequent ionization of a dimer molecule.