TY - JOUR

T1 - Quantum optimal control of electron ring currents in chiral aromatic molecules

AU - Kanno, Manabu

AU - Hoki, Kunihito

AU - Kono, Hirohiko

AU - Fujimura, Yuichi

N1 - Funding Information:
M.K. is grateful to Dr. Y. Teranishi, Professor T. Kato, and Professor Y. Ohtsuki for valuable discussions and acknowledges financial support from a JSPS Research Fellowship for Young Scientists (No. 18∙5252). This work was partly supported by a JSPS Research Grant (No. 17350004).

PY - 2007

Y1 - 2007

N2 - We report the results of optimal control simulations of π -electron rotation (ring current) in a six-membered chiral aromatic molecule, 2,5-dichloro [n] (3,6)pyrazinophane (DCP), attached at a surface and excited by a linearly polarized UV laser. DCP has a pair of optically allowed, quasidegenerate π -electronic excited states. The laser pulse to generate an approximate angular momentum eigenstate consisting of the quasidegenerate states was designed using the global optimal control theory. For both counterclockwise and clockwise π -electron rotations, the calculated objective functional and target yield as a function of the angle of the photon polarization vector show two maxima and two minima. The origin of the two minima is coherent excitation to only one of the quasidegenerate states. The two maxima arise from creation of a superposition of the quasidegenerate states. The optimal control pulse at the maxima is a two-color laser field resonant with the quasidegenerate states. The electric field of the optimal control pulse consists of two parts: a slowly oscillating part with phase ℓenv and a rapidly oscillating one. The phase ℓenv is a crucial parameter for determination of the rotation direction of π electrons at the end of control. The results of the optimal control simulations suggest that π -electron rotation can be controlled by applying a two-color laser field with adjusted phases.

AB - We report the results of optimal control simulations of π -electron rotation (ring current) in a six-membered chiral aromatic molecule, 2,5-dichloro [n] (3,6)pyrazinophane (DCP), attached at a surface and excited by a linearly polarized UV laser. DCP has a pair of optically allowed, quasidegenerate π -electronic excited states. The laser pulse to generate an approximate angular momentum eigenstate consisting of the quasidegenerate states was designed using the global optimal control theory. For both counterclockwise and clockwise π -electron rotations, the calculated objective functional and target yield as a function of the angle of the photon polarization vector show two maxima and two minima. The origin of the two minima is coherent excitation to only one of the quasidegenerate states. The two maxima arise from creation of a superposition of the quasidegenerate states. The optimal control pulse at the maxima is a two-color laser field resonant with the quasidegenerate states. The electric field of the optimal control pulse consists of two parts: a slowly oscillating part with phase ℓenv and a rapidly oscillating one. The phase ℓenv is a crucial parameter for determination of the rotation direction of π electrons at the end of control. The results of the optimal control simulations suggest that π -electron rotation can be controlled by applying a two-color laser field with adjusted phases.

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U2 - 10.1063/1.2806180

DO - 10.1063/1.2806180

M3 - Article

AN - SCOPUS:36549002125

VL - 127

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 20

M1 - 204314

ER -