Imaging ultrafast dynamics of molecules with laser-induced electron diffraction

Area of Science:

• Physical Chemistry
• Molecular Dynamics
• Ultrafast Spectroscopy

Background:

• Ultrafast dynamics of small molecules are crucial for understanding chemical reactions.
• Existing methods often lack the required spatial and temporal resolution.
• Laser-induced electron diffraction (LIED) offers a potential solution.

Purpose of the Study:

• To introduce and validate a novel laser-induced electron diffraction (LIED) method.
• To demonstrate LIED's capability for imaging ultrafast molecular dynamics with high resolution.
• To present the principles and future outlook of LIED.

Main Methods:

• Utilizing femtosecond mid-infrared lasers to ionize molecules.
• Analyzing high-energy photoelectron spectra based on quantitative rescattering (QRS) theory.
• Extracting electron-ion scattering differential cross sections (DCS) as molecular diffraction images.

Main Results:

• Demonstrated sub-angstrom spatial resolution for determining atomic positions.
• Achieved few-femtosecond temporal resolution for dynamic imaging.
• Observed a 0.1 Å shortening of the oxygen molecule bond length within five femtoseconds after ionization.

Conclusions:

• LIED is a powerful new technique for ultrafast molecular imaging.
• The method provides unprecedented spatial and temporal resolution.
• LIED opens new avenues for studying dynamic processes in molecules.