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

Abstract

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.

Time-dependent generalized-active-space configuration-interaction approach to photoionization dynamics of atoms and molecules

“…Up to now, in particular the time-dependent R-Matrix theory [16][17][18][19] and the multi-configurational time-dependent Hartree Fock (MCTDHF) method [13,[20][21][22][23][24][25] have found applications in the photoionization community. In the perturbative regime for the matter-light interaction, the MCTDHF method has been applied to the determination of innershell photoionization cross sections for molecular hydrogen fluoride [25]. The number of configurations in the MCTDHF method increases exponentially with respect to the number of electrons due to the full-CI expansion.…”

“…In addition, we mention the time-dependent density functional theory [8], timedependent natural orbital theory [9], time-dependent coupled-cluster theory [10], the non-equilibrium Green's functions approaches [11][12][13], and the state-specific expansion approach [14,15]. Up to now, in particular the time-dependent R-Matrix theory [16][17][18][19] and the multi-configurational time-dependent Hartree Fock (MCTDHF) method [13,[20][21][22][23][24][25] have found applications in the photoionization community. In the perturbative regime for the matter-light interaction, the MCTDHF method has been applied to the determination of innershell photoionization cross sections for molecular hydrogen fluoride [25].…”

Ultrafast population transfer to excited valence levels of a molecule driven by x-ray pulses

“…Unfortunately, as we found in our prior studies of photoionization [33,34] tions simply do not correspond to those calculated from differences in energies between MCSCF wave functions using the same configuration basis. We have therefore performed a series of calculations to MCTDHF calculations to provide estimates of the transition energies and detunings for an experimental realization of the stimulated Raman population transfer described here.…”

“…In a recently described numerical implementation [33,34] that we use here, all electrons are active, all orbitals are time-dependent, and any number of them may be ionized. Because the orbitals are time-dependent, a converged calculation may be obtained using a far smaller orbital basis than would be required in standard configuration interaction treatments.…”

Unified view on linear response of interacting identical and distinguishable particles from multiconfigurational time-dependent Hartree methods

“…[41][42][43][44][45]; see, e.g., Refs. [46][47][48][49][50][51][52][53][54][55] for applications. MCTDH for bosons (MCTDHB) was derived in Refs.…”