Wave packet dynamics in doubly excited states of He

We have developed a method for the ab initio simulation of the interaction of ultrashort laser pulses with helium atoms. We expand the two-electron Schr\"odinger equation in coupled spherical harmonics and perform direct time integration utilizing either the Arnoldi-Lanczos or the Leapfrog method. The spatial discretization is performed in an FEDVR basis~[1]. This allows for a numerically accurate description while possessing desirable computational features, e.g. a block-diagonal form of the kinetic energy matrix. We will present results on electron-electron correlation and wave packet dynamics in He. By using a suitable combination of attosecond XUV/EUV pulses, we prepare a wave packet in the doubly excited states of helium. The motion of this wave packet can be observed by using a probe pulse to induce ionization. We aim for a detailed understanding of the process by a careful study of the ionized electrons, e.g. by investigating doubly differential momentum spectra. \renewcommand{\labelenumi}{[\arabic{enumi}]}\begin{enumerate} \item B.~I. Schneider and L.~A. Collins. \emph{J. Non-Cryst. Solids} \textbf{351}, 1551. \end{enumerate}