Imaging charge transfer in iodomethane upon x-ray photoabsorption

Area of Science:

• Chemical Physics
• Molecular Dynamics
• Ultrafast Spectroscopy

Background:

• Charge transfer dynamics are crucial in chemical reactions but challenging to observe directly.
• Understanding charge localization and transfer is key to controlling molecular processes.

Purpose of the Study:

• To visualize and quantify charge rearrangement dynamics in gas-phase iodomethane.
• To determine the spatial range of electron transfer during molecular dissociation.

Main Methods:

• Utilized ultrashort X-ray free-electron laser (XFEL) pulses for high temporal resolution.
• Employed synchronized near-infrared (NIR) laser pulses to induce and control molecular dissociation.
• Performed inner-shell photoionization to create localized positive charge on the iodine atom.

Main Results:

• Successfully imaged charge rearrangement dynamics during iodomethane dissociation.
• Observed signatures of electron transfer between methyl and iodine fragments up to 20 angstroms.
• Validated findings using a classical over-the-barrier model to estimate the effective spatial range of electron transfer.

Conclusions:

• The XFEL-based technique provides spatiotemporal imaging of charge transfer dynamics.
• Electron transfer is effective over significant distances in dissociating molecules.
• This method is broadly applicable for studying charge transfer in diverse molecular systems.