Toward ab-initio simulations of multiple ionization processes in intense laser field

A non-variational Time-Dependent Multi-Configuration Self-Consistent Field (TDMCSCF) scheme has been developed [16] to describe, by an ab-initio approach, the time-resolved electron dynamics of a laser-driven many-electron atomic or molecular system. Its implementation within a typical quantum chemical package is discussed and its use demonstrated on the laser-driven electron dynamics of LiH. As an L2 method, this approach faces severe challenges when ionization and large-amplitude electronic motions are addressed. We present here an extension of this TDMCSCF scheme to include multiple ionization processes, using a Feschbach state-partitioning formalism, allowing the bound electrons' dynamics to be treated by the L2-TDMCSCF method, while the ionized electrons can be treated separately by an alternative approach. We present results of proof-of-principle calculations on the strong field ionization of H2 and discuss the effect of the carrier-envelope phase (CEP) on electron localization and ionization processes in this model system.