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Generation and Coherent Control of Pulsed Quantum Frequency Combs
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Quantum optimal control of electron ring currents in chiral aromatic molecules
Manabu Kanno1, Kunihito Hoki, Hirohiko Kono
1Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
The Journal of Chemical Physics
|December 7, 2007
Summary
Researchers used optimal control simulations to steer pi-electron rotation in a chiral molecule. They found that a two-color laser field with controlled phases can direct electron ring currents, offering precise control over molecular electronic behavior.
Area of Science:
- Molecular Quantum Control
- Photochemistry
- Aromatic Systems
Background:
- Pi-electron ring currents in aromatic molecules are fundamental to their electronic properties.
- Controlling these currents is key to manipulating molecular behavior.
- 2,5-dichloro[n](3,6)pyrazinophane (DCP) is a chiral molecule with relevant electronic states.
Purpose of the Study:
- To investigate the feasibility of controlling pi-electron rotation (ring current) in DCP using optimal control theory.
- To determine the influence of laser pulse characteristics on the direction and magnitude of pi-electron rotation.
- To explore the role of quasidegenerate electronic states in controlling electron dynamics.
Main Methods:
- Optimal control simulations were employed to design laser pulses.
- A linearly polarized UV laser was used to excite the DCP molecule.
- Global optimal control theory was applied to generate specific angular momentum eigenstates.
Main Results:
- Simulations revealed that pi-electron rotation can be controlled by a two-color laser field.
- The phase of the laser pulse's envelope (phi(env)) critically determines the direction of electron rotation.
- Two maxima and minima in yield were observed, corresponding to single-state excitation and superposition states, respectively.
Conclusions:
- Precise control over pi-electron rotation in DCP is achievable through tailored laser pulses.
- Two-color laser fields with adjustable phases offer a pathway to direct ring currents.
- This work demonstrates a method for manipulating electronic wavepackets in chiral aromatic molecules.
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