Single photoionization of Be and HF using the multiconfiguration time-dependent Hartree-Fock method

A recently developed ab initio implementation of the muticonfiguration time-dependent Hartree Fock (MCTDHF) method is used to calculate valence and core photoionization cross sections of the Be atom and HF molecule in the Born-Oppenheimer approximation. The cross sections are extracted from the dynamics following excitation by a single subfemtosecond laser pulse. We compare with previously published results and those from time-independent complex Kohn scattering calculations and find that the MCTDHF method calculates both the magnitude of the cross section and the line shapes of the resonant peaks to good accuracy, particularly for valence photoionization. These calculations demonstrate a methodology immediately applicable to calculating multiphoton and ultrafast dynamics.