Electron correlation in tunneling ionization of diatomic molecules: An application of the many-electron weak-field asymptotic theory with a generalized-active-space partition scheme

The many-electron weak-field asymptotic theory (ME-WFAT) for static tunneling ionization [O. I. Tolstikhin et al., Phys. Rev. A 89, 013421 (2014)] is applied to diatomic molecules. In the ME-WFAT, the dependence of the ionization rate on the molecular orientation with respect to the static field direction is determined by the structure factor, which in turn depends on the asymptotic tail of the Dyson orbital. We extract the latter by the timedependent generalized-active-space configuration-interaction method [S. Bauch et al., Phys. Rev. A 90, 062508 (2014)], which takes into account electron correlation effects systematically. Results for the orientation-dependent structure factor are presented for H-2 and LiH. Compared to mean-field Hartree-Fock results, the inclusion of electron-electron correlation affects the structure factor, and hence the rate, even for these simple systems.