Conformer-specific photochemistry imaged in real space and time

Area of Science:

• Chemical dynamics
• Molecular imaging
• Spectroscopy

Background:

• Conformational isomers (conformers) are crucial in biological and chemical processes.
• Existing experimental methods often lack sensitivity to specific conformers during reactions.

Purpose of the Study:

• To investigate the role of molecular conformers in chemical reaction dynamics.
• To directly observe the real-time evolution of conformers during a photoinduced electrocyclic ring-opening reaction.

Main Methods:

• Gas-phase megaelectronvolt ultrafast electron diffraction (UED).
• Nonadiabatic quantum molecular dynamics simulations.

Main Results:

• Direct imaging of specific α-phellandrene conformers transitioning into product isomers.
• Experimental data quantitatively matched simulation predictions.
• Detailed insights into how conformation affects reaction timescale and quantum efficiency.

Conclusions:

• Conformer-specific dynamics can be experimentally resolved using UED.
• Molecular conformation significantly influences the kinetics and efficiency of photoinduced reactions.
• UED provides a powerful tool for studying reaction mechanisms at the conformer level.