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This paper investigates the laser-driven quantum dynamics of positronium (Ps), PsH, and PsCl using time-dependent Hartree-Fock theory with a spherical polar pseudospectral representation to accurately model continuum dynamics. The study reveals that the presence of a positron delays electron ionization in PsH but enhances it slightly in PsCl, with the positron response being faster than that of the electrons in both cases. The authors propose that PsCl formation can be directly observed through photopositron spectra in the multiphoton regime due to distinct energy peaks.
Positrons don't always behave as expected: they delay electron ionization in PsH but enhance it in PsCl when exposed to lasers.
We present a computational study of the laser-driven quantum dynamics of positronium (Ps), PsH, and PsCl at the time-dependent Hartree-Fock level of theory. To eliminate finite-basis effects and to properly capture continuum dynamics, we use a spherical polar pseudospectral representation. The multicomponent theory and its implementation are described in detail. We find that while the presence of the positron delays electron ionization in PsH, a slight enhancement of electron ionization is observed in PsCl. In both cases, the positronic response is faster than that of the electrons. We propose that the formation of PsCl may be directly observed through photopositron spectra in the multiphoton regime, where PsCl peaks are expected at roughly twice the energy of Ps peaks, making PsCl clearly distuinguishable from Ps. In the tunelling regime, however, photopositron rescattering peaks may only be distuinguishable if the amount of Ps is sufficiently low.
