General model and toolkit for the ionization of three or more electrons in strongly driven molecules using an effective Coulomb potential for the interaction between bound electrons

We formulate a general three-dimensional semiclassical model for the study of correlated multielectron escape during fragmentation of molecules driven by intense infrared laser pulses. We do so in the context of triple ionization of strongly driven HeH2+. Our model fully accounts for the singularity in the Coulomb potentials of a recolliding electron with the core and a bound electron with the core as well as for the interaction of a recolliding electron with a bound electron. This model also accounts for the magnetic field of the laser pulse. To avoid artificial autoionization, our model employs effective potentials to treat the interaction between bound electrons. We focus on triple and double ionization as well as frustrated triple and frustrated double ionization. In these processes, we identify and explain the main features of the sum of the kinetic energies of the final ion fragments. We find that frustrated double ionization is a major ionization process, and we identify the different channels and hence different final fragments that are obtained through frustrated double ionization. Also, we discuss the differences between frustrated double and triple ionization.