Femtosecond gas phase electron diffraction with MeV electrons

Area of Science:

• Physics
• Chemistry
• Materials Science

Background:

• Ultrafast gas electron diffraction (UGED) is crucial for studying molecular dynamics.
• Previous UGED methods lacked the necessary temporal resolution for nuclear motion.
• Investigating molecular reactions requires probing at femtosecond timescales.

Purpose of the Study:

• To present results from ultrafast gas electron diffraction (UGED) experiments with femtosecond resolution.
• To detail the use of MeV electron pulses for enhanced temporal resolution in UGED.
• To overcome challenges in achieving femtosecond resolution for molecular dynamics studies.

Main Methods:

• Utilized MeV electron pulses from SLAC National Accelerator Laboratory for UGED.
• Overcame velocity mismatch between laser and electron pulses at >3 MeV.
• Minimized temporal broadening effects on relativistic electrons.
• Characterized a new UGED setup for static and time-resolved diffraction.

Main Results:

• Achieved a temporal resolution of 100 fs root-mean-square.
• Obtained sub-angstrom spatial resolution in diffraction measurements.
• Successfully captured static diffraction patterns and performed time-resolved experiments.
• Demonstrated negligible velocity mismatch for relativistic electrons (>3 MeV).

Conclusions:

• MeV electron pulses significantly advance UGED capabilities for molecular dynamics.
• The new setup provides unprecedented temporal and spatial resolution.
• Future improvements will focus on enhancing temporal and spatial resolution further.
• UGED with MeV electrons opens new avenues for ultrafast chemical reaction studies.