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Low-kinetic energy photoelectron detachment experiments have revealed the unexpected dependence of transition intensities on photon energy, which is hypothesized to result from time-dependent coupling between low-kinetic energy photoelectrons and the remnant molecule. This study explores how the kinetic energy and detachment axis of the photoelectron influence the interaction and modify the final remnant electronic structure. Using real-time simulations on several model systems (H2, NO, N2, and C2 hydrocarbons), this study demonstrates that electron-remnant interactions are strongly dependent on the detachment orientation, electron kinetic energy, and remnant electronic structure. The results reveal that higher kinetic energies lead to significant nonadiabatic transitions, while lower kinetic energies yield more adiabatic behavior. While generally lower kinetic energies show prolonged electron-remnant interactions, the extent of temporal and spatial interactions does not necessarily vary linearly with the kinetic energy, and the final remnant electronic structure is found to be very sensitive to the exact nature of the photoelectron-remnant interactions. In addition, the point charge model employed for the photoelectron provides a useful approach for the deconvolution of more complete simulations to provide deeper insights into the specific photoelectron-remnant interactions that determine the eventual remnant wavefunction. The findings underscore the importance of considering both temporal and spatial electron dynamics in understanding low-kinetic energy photodetachment processes and provide a foundation for a further exploration of electron-molecule interactions in the low-energy regime., (© 2025 Author(s). Published under an exclusive license by AIP Publishing.)

The results of a combined experimental and computational study on Ln3O (Ln = Ce, Sm, and Gd) anion and neutral clusters are presented and analyzed. These three Ln's were specifically targeted because they vary in their spin state and orbital angular momentum associated with the 4fN subshell occupancies. From the anion PE spectra of Ce3O-, Sm3O-, and Gd3O- measured with 2.330 and 3.495 eV photon energies, we determine the adiabatic electron affinities of the corresponding neutrals to be 0.83 ± 0.03, 1.11 ± 0.05, and 1.17 ± 0.05 eV, respectively. The lowest energy features in all three spectra can readily be reconciled with molecular structures in which the O-atom is central to all three Ln centers, with Ce3O-/Ce3O assuming pyramidal structures and Sm3O-/Sm3O and Gd3O-/Gd3O assuming planar structures. Computationally, the lowest-energy structure of neutral Ce3O is a kite-like structure, which is not consistent with the observed spectrum. The kite-like and pyramidal structures of Ce3O- are predicted to be nearly isoenergetic. Electronic states in which all three 4fN centers are ferromagnetically coupled are predicted to be energetically favored for all species, but spin-frustrated states in which one 4fN center is antiferromagnetically coupled to the remaining centers are computed to lie 0.05 eV higher in energy than the FM-coupled states for Ce3O- and Sm3O-. The PE spectrum of Sm3O- exhibits striking anomalies in the photoelectron angular dependence. This effect is attributed to strong photoelectron-valence electron interactions that drive nominally forbidden changes in the Mf state of the remnant neutral., (© 2025 Author(s). Published under an exclusive license by AIP Publishing.)