Atomic photoionization dominated by doubly-excited resonances.

Abstract We present an extended theoretical study of two-colour doubly resonant photoionization of helium involving two doubly excited states below the N = 2 ionization threshold. We model the effects of a strong laser coupling between the lowest 1 P o and the selected 1 S e , 1 P e and 1 D e doubly excited states on the photoelectron (photoion) yield by taking into account the spatio-temporal structure of the pulses and by considering the effects of the neighbouring resonance states. We show that the laser coupling results in a measurable modification of the line profiles and in a reduction of the photoelectron yield under resonant or near-resonant conditions.Abstract We present an extended theoretical study of two-colour doubly resonant photoionization of helium involving two doubly excited states below the N = 2 ionization threshold. We model the effects of a strong laser coupling between the lowest 1 P o and the selected 1 S e , 1 P e and 1 D e doubly excited states on the photoelectron (photoion) yield by taking into account the spatio-temporal structure of the pulses and by considering the effects of the neighbouring resonance states. We show that the laser coupling results in a measurable modification of the line profiles and in a reduction of the photoelectron yield under resonant or near-resonant conditions.

Journal of Physics B Atomic Molecular and Optical PhysicsOct 26, 20176 citations

Two-center resonant photoionization-excitation driven by combined intra- and interatomic electron correlations

S Kim, S Steinhäuser, Alexander B Voitkiv +1 more

Abstract Ionization-excitation of an atom induced by the absorption of a single photon in the presence of a neighboring atom is studied. The latter is, first, resonantly photoexcited and, afterwards, transfers the excitation energy radiationlessly to the other atom, leading to its ionization with simultaneous excitation. The process relies on the combined effects of interatomic and intraatomic electron correlations. Under suitable conditions, it can dominate by several orders of magnitude over direct photoionization-excitation and even over direct photoionization. In addition, we briefly discuss another kind of two-center resonant photoionization with excitation where the ionization and residual excitation in the final state are located at different atomic sites.Abstract Ionization-excitation of an atom induced by the absorption of a single photon in the presence of a neighboring atom is studied. The latter is, first, resonantly photoexcited and, afterwards, transfers the excitation energy radiationlessly to the other atom, leading to its ionization with simultaneous excitation. The process relies on the combined effects of interatomic and intraatomic electron correlations. Under suitable conditions, it can dominate by several orders of magnitude over direct photoionization-excitation and even over direct photoionization. In addition, we briefly discuss another kind of two-center resonant photoionization with excitation where the ionization and residual excitation in the final state are located at different atomic sites.

arXiv:2309.01143Journal of Physics B Atomic Molecular and Optical PhysicsJan 30, 20240 citations

Complete Experiments in Atomic Photoionization

Hans Kleinpoppen, Bernd Lohmann, Alexei N. Grum-Grzhimailo

Springer series on atomic, optical, and plasma physicsJan 1, 20132 citations

Photoionization of atomic systems

Philip George Burke

Elsevier eBooksJan 1, 19766 citations

Photoionization spectroscopy of Yb I from the 6s7sS01 state in the presence of a static electric field

Christophe Blondel, René-Jean Champeau, Christian Delsart

Laser investigation of the photoionization spectra in the presence of an electric field has been performed in $\ensuremath{\pi}$ and $\ensuremath{\sigma}$ polarizations on an ytterbium atomic beam from the particular level $4{f}^{14}6s7s^{1}S_{0}$ which was populated by a two-step excitation. Broad modulations (in $\ensuremath{\pi}$ polarization) and Stark resonances in the vicinity of the zero-field ionization limit are interpreted satisfactorily as in the case of alkali atoms. However, the photoionization spectra are deeply affected by the presence of two perturbing levels belonging to the configuration $4{f}^{13}5{d}^{2}6s$ . This phenomenon is explained by strong interference effects between the structured Stark continuum and the field-induced autoionizing states corresponding to the doubly excited levels.Laser investigation of the photoionization spectra in the presence of an electric field has been performed in $\ensuremath{\pi}$ and $\ensuremath{\sigma}$ polarizations on an ytterbium atomic beam from the particular level $4{f}^{14}6s7s^{1}S_{0}$ which was populated by a two-step excitation. Broad modulations (in $\ensuremath{\pi}$ polarization) and Stark resonances in the vicinity of the zero-field ionization limit are interpreted satisfactorily as in the case of alkali atoms. However, the photoionization spectra are deeply affected by the presence of two perturbing levels belonging to the configuration $4{f}^{13}5{d}^{2}6s$. This phenomenon is explained by strong interference effects between the structured Stark continuum and the field-induced autoionizing states corresponding to the doubly excited levels.

Physical Review AJan 1, 198312 citations

4{f}^{14}6s7s^{1}S_{0}

which was populated by a two-step excitation. Broad modulations (in $\ensuremath{\pi}$ polarization) and Stark resonances in the vicinity of the zero-field ionization limit are interpreted satisfactorily as in the case of alkali atoms. However, the photoionization spectra are deeply affected by the presence of two perturbing levels belonging to the configuration

4{f}^{13}5{d}^{2}6s

. This phenomenon is explained by strong interference effects between the structured Stark continuum and the field-induced autoionizing states corresponding to the doubly excited levels.