Programme

O.7 -- Oral, VCTP-51

Date: Monday, 3 August 2026

Time: 16:40 - 17:00

Unidirectional pi-electron rotations for the helical-photo-dressed states in aromatic ring molecules

Hirobumi Mineo^1, Quang Huy Ho^2, and Ngoc Loan Phan^3

1 Science and Technology Advanced Institute (STAI), Van Lang University, Ho Chi Minh City, Vietnam 2 Faculty of Engineering Technology, University of Phan Thiet, Lam Dong, Vietnam 3 Department of Physics, Ho Chi Minh City University of Education, Ho Chi Minh City, Vietnam

Controlling the unidirectional rotation of π-electrons is a key challenge in the development of organic electronic and optoelectronic devices [1-4]. In our recent study [5, 6], we explored the generation of unidirectional π-electron rotations in both low- and high-symmetry molecules by utilizing helical photon-dressed states. These states were formed using circularly or elliptically polarized laser fields within a minimal three-state electronic model under the frozen-nuclei approximation. However, that approach did not address the preparation of appropriate initial conditions or the tailored light–matter interactions required to create photon-dressed states. To overcome this limitation, it is crucial to consider a process that prepares the photon-dressed states from the electronic ground state through optical pumping with pulsed lasers. In this work, we analytically design such pulsed lasers to induce helical photon-dressed states in aromatic rings, starting from the ground state. We further incorporate the nuclear vibrational effects within the adiabatic approximation, and apply those designed laser fields. Finally, we numerically demonstrate the generation of angular momenta associated with the photon-dressed states using the analytically designed laser fields. Here, we employ the toluene molecule as a typical aromatic ring molecule with low-symmetry. References [1] D. Jia, C. Liu, J. Manz, Y. Wang, and Y. Yang, “Prolongation of electronic coherence for ultralong-lived charge migration anchored by a continuous-wave laser,” Phys. Rev. A 111(2), 022807 (2025). [2] I. Barth, and J. Manz, “Periodic electron circulation induced by circularly polarized laser pulses: quantum model simulations for Mg porphyrin,” Angew. Chem. Int. Ed Engl. 45(18), 2962–2965 (2006). [3] Q.Y. Xu, Y.L. He, S.J. Yan, and J. Guo, “Electronic ring current and magnetic field generation induced by current-carrying states of ring molecules in intense fields,” J. Phys. B: At. Mol. Opt. Phys. 56(3), 035401 (2023). [4] M. Kanno, H. Kono, Y. Fujimura, and S.H. Lin, “Nonadiabatic response model of laser-induced ultrafast pi-electron rotations in chiral aromatic molecules,” Phys. Rev. Lett. 104(10), 108302 (2010). [5] H. Mineo, Q.H. Ho, N.L. Phan, G.-S. Kim, and Y. Fujimura, “Helical-photon-dressed states determining unidirectional π-electron rotations in aromatic ring molecules,” J. Chem. Phys. 161(19), 194311 (2024). [6] H. Mineo, Q.H. Ho, N.L. Phan, accepted to J. Chem. Phys. (2026).

Presenter: Mineo Hirobumi