Control of photoelectric effect of Helonium molecule by an arbitrarily polarized extreme ultraviolet laser pulse
ORAL
Abstract
We theoretically investigate the Einstein's photoelectric effect in the helonium (HeH$^+$) molecule driven by an arbitrarily polarized extreme-ultraviolet (XUV) pulse$^{1}$. The main objective is to examine the impact of the asymmetric electron distribution of the initial bound state on the photoelectron momentum distribution (PMD) and the probability current density (PCD). This study focuses on the role of the initial electronic structure, in particular the asymmetry of the highest-occupied molecular orbital (HOMO), and its influence on photoelectron emission.
Solving the full-dimensional time-dependent Schr\"{o}dinger equation (TDSE) within the time-dependent R-matrix (RMT) method$^{2,3}$ for the basic two-electron molecular systems, we perform a comparative study between fixed-in-space H$_2$, whose HOMO is symmetric, and aligned HeH$^+$, which possesses a single asymmetric doubly occupied orbital with a large permanent electric dipole moment. We show that the resulting PMDs and PCDs exhibit identical qualitative patterns consistent with the Heisenberg uncertainty principle and are strongly sensitive to orbital symmetry, molecular orientation, and light polarization. Our simulations thus allow to watch the PMD arise asymptotically in the shape of the coordinate space PCD. Our TDSE results are analyzed using first-order perturbation theory.
For H$_2$, linear polarization produces dipolar structures, while circular polarization leads to yin-yang-like distributions displaying dichroism. In contrast, HeH$^+$ driven by linear polarized light exhibits a pronounced mono-polar asymmetry, while circular polarization generates distinct lung-like patterns with dichroic behavior. Our study including nuclear motions in the initial and final states demonstrates full control of the linear process of one-photon single ionization for the basic two-electron molecular systems.
Solving the full-dimensional time-dependent Schr\"{o}dinger equation (TDSE) within the time-dependent R-matrix (RMT) method$^{2,3}$ for the basic two-electron molecular systems, we perform a comparative study between fixed-in-space H$_2$, whose HOMO is symmetric, and aligned HeH$^+$, which possesses a single asymmetric doubly occupied orbital with a large permanent electric dipole moment. We show that the resulting PMDs and PCDs exhibit identical qualitative patterns consistent with the Heisenberg uncertainty principle and are strongly sensitive to orbital symmetry, molecular orientation, and light polarization. Our simulations thus allow to watch the PMD arise asymptotically in the shape of the coordinate space PCD. Our TDSE results are analyzed using first-order perturbation theory.
For H$_2$, linear polarization produces dipolar structures, while circular polarization leads to yin-yang-like distributions displaying dichroism. In contrast, HeH$^+$ driven by linear polarized light exhibits a pronounced mono-polar asymmetry, while circular polarization generates distinct lung-like patterns with dichroic behavior. Our study including nuclear motions in the initial and final states demonstrates full control of the linear process of one-photon single ionization for the basic two-electron molecular systems.
*Research is supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award No. DE-SC0021054.
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Publication: [1] H. B. Ambalampitiya, I. Sabry Khalil, and J. M. Ngoko Djiokap, (manuscript submitted to J. Phys. B).
[2] A. C. Brown \textit {et al.}, Comp. Phys. Comm., {\bf 250}, 107062 (2022).
[3] H. B. Ambalampitiya and J. M. Ngoko Djiokap, Communications Physics {\bf 7}, 359 (2024).
Presenters
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Islam Sabry Khalil
- University of Nebraska-Lincoln & Cairo University