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Two-photon double ionization with finite pulses: Application of the virtual sequential model to helium



Barry I. Schneider, luca argenti, Siddhartha Chattopadhyay, carlos marante, Jeppe Olsen


As a step toward the full ab-initio description of two-photon double ionization processes, we present a finitepulse version of the virtual-sequential model for polyelectronic atoms. The model relies on the ab initio description of the single ionization scattering states of both the neutral and ionized target system. As a proof of principle and a benchmark, the model is applied to the helium atom using the NewStock atomic photoionization code. The results of angularly integrated observables, which are in good agreement with existing TDSE (time-dependent Schroedinger equation) simulations, show how the model is able to capture the role of electron correlation in the non-sequential regime at a comparatively modest computational cost. The model also reproduces the two-particle interference with ultrashort pulses, which is within reach of current experimental technologies. Furthermore, the model shows the modulation of the joint energy distribution in the vicinity of autoionizing states, which can be probed with XUV pulses of duration much longer than the characteristic lifetime of the resonance. The formalism discussed here applies also to polyelectronic atoms and molecules, thus opening a window on non-sequential and sequential double ionization in these more complex systems.
Physical Review A (Atomic, Molecular and Optical Physics)


double ionization, time dependent perturbation theory, attosecond electron dynamivs


Schneider, B. , Argenti, L. , Chattopadhyay, S. , marante, C. and Olsen, J. (2023), Two-photon double ionization with finite pulses: Application of the virtual sequential model to helium, Physical Review A (Atomic, Molecular and Optical Physics), [online],, (Accessed April 23, 2024)
Created July 20, 2023, Updated March 27, 2024