Manipulating nonsequential double ionization via alignment of asymmetric molecules

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Laser-Matter Interactions

Background:

• Nonsequential double ionization (NSDI) is a complex quantum phenomenon crucial for understanding electron correlation.
• Molecular alignment significantly influences photoionization dynamics, but its effect on NSDI in heteronuclear molecules is less explored.
• HeH+ presents a unique system for studying NSDI due to its simple heteronuclear structure.

Purpose of the Study:

• To investigate the influence of molecular axis alignment on the nonsequential double ionization of HeH+ ions in intense laser fields.
• To analyze how controlling molecular orientation affects electron momentum distributions and total ionization yields.
• To explore the role of electron correlation in NSDI of molecules.

Main Methods:

• Utilized classical three-dimensional ensembles to model the interaction of HeH+ with intense laser fields.
• Simulated the nonsequential double ionization process by varying the alignment angle of the molecular axis relative to the laser polarization.
• Analyzed the correlated electron momentum spectra and total double ionization yields as a function of molecular alignment.

Main Results:

• Demonstrated that both the total double ionization yield and the symmetry of the correlated electron momentum spectrum are strongly dependent on molecular alignment.
• Observed that aligning the HeH+ molecular axis parallel to the laser field maximizes the probability of double ionization.
• Found that parallel alignment leads to the most asymmetric correlated electron momentum spectrum with respect to the minor diagonal.

Conclusions:

• Molecular axis alignment is a critical control parameter for manipulating nonsequential double ionization in HeH+.
• The observed dependence of ionization yield and electron momentum spectra on alignment provides insights into electron correlation mechanisms in NSDI.
• This study highlights the potential for controlling molecular ionization dynamics through laser-field-induced alignment.