Core-Valence Attosecond Transient Absorption Spectroscopy of Polyatomic Molecules

Area of Science:

• Physical Chemistry
• Quantum Dynamics
• Molecular Spectroscopy

Background:

• Observing ultrafast electron dynamics in molecules is challenging due to rapid nuclear rearrangements.
• Damping of electronic coherence limits real-time tracking of electron motion.

Purpose of the Study:

• To extend attosecond transient absorption spectroscopy (ATAS) theory for coupled electron-nuclear dynamics in molecules.
• To apply the enhanced ATAS method to study charge oscillations after molecular ionization.

Main Methods:

• Developed an extended theoretical framework for ATAS incorporating coupled electron-nuclear wave packet dynamics.
• Utilized element-specific core-to-valence transitions induced by X-ray radiation.

Main Results:

• Successfully applied the extended ATAS theory to probe outer-valence ionization of propiolic acid.
• Observed oscillations of the positive charge created in the molecule.
• Demonstrated atomic spatial resolution in tracing electron density dynamics.

Conclusions:

• The enhanced ATAS method provides unprecedented insight into ultrafast electron dynamics in molecules.
• Atomic-scale resolution allows detailed observation of charge redistribution and nuclear motion.
• This technique opens new avenues for studying light-induced processes in molecular systems.