Super-resolution femtosecond electron diffraction reveals electronic and nuclear dynamics at conical intersections

Area of Science:

• Physical Chemistry
• Chemical Physics
• Quantum Dynamics

Background:

• Conical intersections are crucial for excited-state quantum dynamics.
• Observing transient molecular structures near conical intersections is difficult due to rapid timescales and subtle changes.

Purpose of the Study:

• To overcome the limitations in visualizing molecular structures at conical intersections.
• To enable visualization of nuclear and electronic motions at conical intersections with sub-angstrom resolution.

Main Methods:

• Combined mega-electron-volt ultrafast electron diffraction (MeV-UED) with a super-resolution real-space inversion algorithm.
• Achieved sub-angstrom resolution, surpassing the conventional diffraction limit.

Main Results:

• Visualized nuclear and electronic motions at conical intersections.
• Applied to the ring-opening reaction of 1,3-cyclohexadiene, observing two conical intersections within 100 femtoseconds.
• Revealed a C-C bond length difference < 0.4 Å and ~30 fs wave packet traversal time.

Conclusions:

• Super-resolution ultrafast scattering is a transformative tool for studying molecular quantum dynamics.
• Opens new avenues for investigating light-matter interactions at the fundamental level.