One-electron ionization of multielectron systems in strong nonresonant laser fields

We present an approach to calculating strong field ionization dynamics of multielectron molecular targets. Adopting a multielectron wave function ansatz based on field-free ab initio neutral and ionic multielectron states, a set of coupled time-dependent single-particle Schr\"odinger equations describing the neutral amplitude and continuum electron are constructed. These equations, amenable to direct numerical solution or further analytical treatment, allow one to study multielectron effects during strong field ionization, recollision, and high-harmonic generation. We apply the method to strong field ionization of CO₂ and suggest the importance of intermediate core excitation to explain the previous failure of analytical models to reproduce experimental ionization yields for this molecule.