High-harmonic spectroscopy of transient two-center interference calculated with time-dependent density-functional...

Area of Science:

• Quantum Chemistry
• Attosecond Science
• Molecular Spectroscopy

Background:

• High-harmonic generation (HHG) is a powerful tool for probing electron dynamics in atoms and molecules.
• Extracting molecular-frame information from HHG signals is crucial for understanding complex molecular processes.

Purpose of the Study:

• To demonstrate a computational method for high-harmonic spectroscopy in many-electron molecules.
• To extract spectral amplitude and target-specific phase from HHG signals.
• To achieve molecular-frame resolution for studying electron rescattering dynamics.

Main Methods:

• Time-dependent density-functional theory (TDDFT) simulations.
• Synchronization of an attosecond-pulse-train ionization seed with a mid-infrared laser field.
• Analysis of high-harmonic generation (HHG) signals for spectral amplitude and phase extraction.
• Processing HHG signals for molecular-frame resolution.

Main Results:

• Demonstrated experimentally relevant HHG signals using a synchronized ionization seed.
• Successfully extracted spectral amplitude and target-specific phase (group delay).
• Achieved molecular-frame resolution to distinguish rescattering from different molecular sides.
• Investigated transient two-center interference and subcycle polarization effects in CO2 and OCS.

Conclusions:

• The developed TDDFT framework enables high-harmonic spectroscopy with molecular-frame resolution.
• This method allows detailed investigation of electron dynamics, including two-center interference and polarization effects.
• The findings pave the way for advanced studies of electron behavior in oriented molecules.