Photoelectron angular distribution in two-pathway ionization of neon   with femtosecond XUV pulses
  We analyze the photoelectron angular distribution in two-pathway interference between non\-resonant one-photon and resonant two-photon ionization of neon. We consider a bichromatic femtosecond XUV pulse whose fundamental frequency is tuned near the $2p^5 3s$ atomic states of neon. The time-dependent Schr\"odinger equation is solved and the results are employed to compute the angular distribution and the associated anisotropy parameters at the main photoelectron line. We also employ a time-dependent perturbative approach, which allows obtaining information on the process for a large range of pulse parameters, including the steady-state case of continuous radiation, i.e., an infinitely long pulse. The results from the two methods are in relatively good agreement over the domain of applicability of perturbation theory. 
Nicolas Douguet, Elena V. Gryzlova, Ekaterina I. Staroselskaya, Klaus   Bartschat, and Alexei N. Grum-Grzhimailo
physics.atom-ph