Persistent Orbital Magnetism from Light-Induced Attosecond Charge Migration in Linear Molecules.

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Molecular Dynamics

Background:

• Coherent charge migration is crucial for chemical and biological processes on attosecond timescales.
• Light-induced magnetism in molecules is an emerging field with potential applications.

Purpose of the Study:

• To investigate light-induced magnetic behavior in linear polyatomic molecules.
• To demonstrate helical charge migration and magnetic field generation using circularly polarized laser pulses.

Main Methods:

• Excitation of charge-transfer states in oriented lithium cyanide using ultrashort circularly polarized laser pulses.
• Time-resolved electronic current-density mapping to visualize charge flow.

Main Results:

• Observed screw-like helical charge migration in lithium cyanide.
• Generated intense, rapidly oscillating magnetic fields on subfemtosecond timescales.
• Linked helical currents to π → σ charge-transfer excitation.

Conclusions:

• Established a chemically intuitive mechanism for inducing ultrafast circulating currents in linear molecules.
• Demonstrated a route toward engineering molecular magnetism.
• Opened new avenues for controlling electronic currents and magnetic responses in molecules for light-driven functionality.