High harmonic generation and molecular orbital tomography in multielectron systems: beyond the single active electron...

Area of Science:

• Quantum Mechanics
• Atomic and Molecular Physics
• Chemical Physics

Background:

• High harmonic generation (HHG) and molecular orbital (MO) tomography are powerful techniques for probing electronic structures.
• Current theories rely on the single active electron (SAE) approximation, neglecting crucial quantum phenomena like particle indistinguishability and the Pauli exclusion principle.

Purpose of the Study:

• To develop a more accurate theoretical framework for interpreting MO tomography measurements.
• To investigate the role of multielectron wave functions and electronic relaxation in HHG.
• To demonstrate the capability of MO tomography to reconstruct complete electronic wave functions.

Main Methods:

• Development of a theoretical model incorporating fully antisymmetrized multielectron wave functions.
• Inclusion of electronic relaxation effects in the molecular cation.
• Analysis of Dyson orbital and inner-shell exchange contributions to HHG spectra.

Main Results:

• The study shows that MO tomography, when considering multielectron effects, images the Dyson orbital along with exchange contributions from inner shells.
• Mixing of contributions from multiple MOs provides access to richer wave function information.
• The exchange term allows for the interpretation of harmonic emission from a 4-electron system as a complete Hartree-Fock wave function.

Conclusions:

• The findings extend the capabilities of MO tomography beyond the SAE approximation.
• This work provides a pathway to experimentally reconstruct complete electronic wave functions.
• The developed theoretical framework enhances the understanding of HHG processes in molecules.