Single-active-electron approximation for molecules in strong laser fields : Test application to H₂

A new method for solving the electronic three-dimensional time-dependent Schrödinger equation (TDSE) for molecules in ultrashort intense laser fields was developed. In this method the molecules are described within the single-active-electron (SAE) approximation using density-functional theory (DFT). The method and its implementation is tested for H₂ for which a full six-dimensional two-electron solution is obtained via a time-dependent configuration-interaction approach. For larger molecular systems (for which no full solution is possible) the novel SAE method can, e.g., be used to test the validity of simplified SAE-based models like the molecular strong-field approximation (MO-SFA) or the molecular-orbital Ammosov-Delone-Krainov (MO-ADK) model.