We present a novel approach to calculating strong field ionization dynamics
of multielectron molecular targets. Adopting a multielectron wavefunction
ansatz based on field-free ab initio neutral and ionic multielectron states, a
set of coupled time-dependent single-particle Schroedinger 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
CO_2, and suggest the importance of intermediate core excitation to explain
previous failure of analytical models to reproduce experimental ionization
yields for this molecule.Comment: 25 pages, 6 figure