Browsing by Author "Ono, Yukari"

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Laser-Polarization Effects on Coherent Vibronic Excitation of Molecules with Quasi-Degenerate Electronic States
(2012-11-22)
Kanno, Manabu
;
Ono, Yukari
;
Kono, Hirohiko
;
Fujimura, Yuichi
;
應用化學系分子科學碩博班
The laser-polarization effects on nonadiabatically couple pi-electron rotation (ring current) and molecular vibration have been theoretically analyzed for aromatic molecules with quasi-degenerate excited states irradiated by an ultrashort laser pulse of arbitrary polarization. We first derived general formulations of the coherent electronic wave packet and expectation value of electronic angular momentum within a frozen-nuclei model. The relative quantum phase of the superposed quasi-degenerate States, which.. determines the oscillating behavior of angular momentum; can be manipulated by the ellipticity and orientation of the incident laser. Nuclear wave packet simulations with a model molecule confirmed the controllability of pi-electron rotation, although the angular momentum is gradually reduced by nonadiabatic couplings. The amplitude of molecular vibration depends prominently on the orientation of linear polarization vectors rather than the helicity of circular polarization. The characteristic feature in vibrational amplitudes is attributed to the interference in nonadiabatic transition governed by the-relative quantum phase between nuclear wave packets. This offers a new strategy for laser control of molecular vibrations through the wave packet interference in nonadiabatic transition.
Nonadiabatically Coupled pi-Electron Rotation and Molecular Vibration in Aromatic Molecules Excited by Polarized UV/Vis Laser Pulses
(2014-02-01)
Kanno, Manabu
;
Ono, Yukari
;
Kono, Hirohiko
;
Fujimura, Yuichi
;
應用化學系分子科學碩博班
We review our theoretical studies on laser-driven ultrafast pi-electron rotation (ring current) and vibronically coupled molecular vibrations in aromatic molecules with quasi-degenerate excited states. The main focus of discussion is on the role of laser polarization in controlling the coherent vibronic dynamics. We first present general formulations of the coherent electronic wave packet and expectation value of electronic angular momentum for arbitrary laser polarization within a frozen-nuclei model. We show that the relative quantum phase of the superposed quasi-degenerate states, which determines the oscillating behavior of angular momentum, can be manipulated by the ellipticity and orientation of the incident laser. The controllability of pi-electron rotation is demonstrated by electronic wave packet simulations for a model molecule. The results of nuclear wave packet simulations on effective potential energy surfaces of the molecule have revealed that the angular momentum is gradually reduced by nonadiabatic transitions. The amplitude of induced molecular vibration depends significantly on the direction of linear polarization vectors but is insensitive to the helicity of circular polarization. The characteristic feature in vibrational amplitudes is attributed to the interference between nuclear wave packets that acquire different quantum phases in nonadiabatic transition. This feature offers a new strategy for laser control of molecular vibrations through the wave packet interference in nonadiabatic transition.