Induction of unidirectional π-electron rotations in low-symmetry aromatic ring molecules using two linearly polarized stationary lasers

2016 ◽  
Vol 18 (38) ◽  
pp. 26786-26795 ◽  
Author(s):  
Hirobumi Mineo ◽  
Masahiro Yamaki ◽  
Gap-Sue Kim ◽  
Yoshiaki Teranishi ◽  
Sheng Hsien Lin ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Excited States ◽  
Ring Molecules ◽  
Linearly Polarized ◽  
Laser Control ◽  
Low Symmetry

A new laser-control scenario of unidirectional π-electron rotations in an aromatic ring molecule having no degenerate excited states is proposed.

The generation of stationary π-electron rotations in chiral aromatic ring molecules possessing non-degenerate excited states

2016 ◽  
Vol 18 (3) ◽  
pp. 1570-1577 ◽  
Author(s):  
Masahiro Yamaki ◽  
Yoshiaki Teranishi ◽  
Hiroki Nakamura ◽  
Sheng Hsien Lin ◽  
Yuichi Fujimura
Keyword(s):  
Angular Momentum ◽  
Aromatic Ring ◽  
Excited States ◽  
High Symmetry ◽  
Laser Fields ◽  
Ring Molecules ◽  
Fundamental Quantity ◽  
Low Symmetry

Stationary angular momentum, which is a fundamental quantity of high-symmetry aromatic ring molecules, can be created for low-symmetry ring molecules by applying theoretically designed stationary laser fields.

scholarly journals Quantum Control of Coherent π-Electron Dynamics in Aromatic Ring Molecules

2021 ◽  
Vol 9 ◽  
Author(s):  
Hirobumi Mineo ◽  
Ngoc-Loan Phan ◽  
Yuichi Fujimura
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Aromatic Ring ◽  
Excited States ◽  
Quantum Control ◽  
Ring Current ◽  
Theoretical Description ◽  
Electron Dynamics ◽  
Ring Molecules ◽  
Electron Ring

Herein we review a theoretical study of unidirectional π-electron rotation in aromatic ring molecules, which originates from two quasi-degenerate electronic excited states created coherently by a linearly polarized ultraviolet/visible laser with a properly designed photon polarization direction. Analytical expressions for coherent π-electron angular momentum, ring current and ring current-induced magnetic field are derived in the quantum chemical molecular orbital (MO) theory. The time evolution of the angular momentum and the ring current are expressed using the density matrix method under Markov approximation or by solving the time-dependent Schrödinger equation. In this review we present the results of the following quantum control scenarios after a fundamental theoretical description of coherent angular momentum, ring current and magnetic field: first, two-dimensional coherent π-electron dynamics in a non-planar (P)-2,2’-biphenol molecule; second, localization of the coherent π-electron ring current to a designated benzene ring in polycyclic aromatic hydrocarbons; third, unidirectional π-electron rotations in low-symmetry aromatic ring molecules based on the dynamic Stark shift of two relevant excited states that form a degenerate state using the non-resonant ultraviolet lasers. The magnetic fields induced by the coherent π-electron ring currents are also estimated, and the position dependence of the magnetic fluxes is demonstrated.

scholarly journals Vibrational effect on unidirectional time-dependent angular momentum in low-symmetry aromatic ring molecule induced by two linearly polarized UV laser

2019 ◽  
Vol 16 (6) ◽  
pp. 62
Author(s):  
La Dung Kiet ◽  
Hirobumi Mineo
Keyword(s):  
Angular Momentum ◽  
Aromatic Ring ◽  
Theoretical Study ◽  
Momentum Equation ◽  
Time Dependent ◽  
Uv Laser ◽  
Toluene Molecule ◽  
Linearly Polarized ◽  
Low Symmetry

In this study, we present the results of a theoretical study of the time-dependent angular momentum equation for low-symmetry aromatic ring molecule combine with vibrational effect using two linearly polarized UV laser. We consider the vibrational effect on Toluene molecule and show how the vibrational effect to change of the oscillation periods of unidirectional angular momentum.

Coherent Ring Currents in Chiral Aromatic Molecules Induced by Linearly Polarized UV Laser Pulses

2013 ◽  
Vol 543 ◽  
pp. 381-384 ◽  
Author(s):  
Manabu Kanno ◽  
Hirohiko Koho ◽  
Hirobumi Mineo ◽  
Sheng Hsien Lin ◽  
Yuichi Fujimura
Keyword(s):  
Aromatic Ring ◽  
Quantum Dynamics ◽  
Ring Current ◽  
Molecular System ◽  
Laser Pulses ◽  
Uv Laser ◽  
Aromatic Molecules ◽  
Ring Currents ◽  
Linearly Polarized ◽  
Coherent Ring

In recent years, laser control of electrons in molecular system and condensed matter has attracted considerable attention with rapid progress in laser science and technology [. In particular, control of π-electron rotation in photo-induced chiral aromatic molecules has potential utility to the next-generation ultrafast switching devices. In this paper, we present a fundamental principle of generation of ultrafast coherent ring currents and the control in photo-induced aromatic molecules. This is based on quantum dynamics simulations of π-electron rotations and preparation of unidirectional angular momentum by ultrashort UV laser pulses properly designed. For this purpose, we adopt 2,5-dichloro [(3,6) pyrazinophane (DCPH) fixed on a surface, which is a real chiral aromatic molecule with plane chirality. Here π electrons can be rotated along the aromatic ring clockwise or counterclockwise by irradiation of a linearly polarized laser pulse with the properly designed photon polarization direction and the coherent ring current with the definite direction along the aromatic ring is prepared. This is contrast to ordinary ring current in an achiral aromatic ring molecule with degenerate electronic excited state, which is prepared by a circularly polarized laser [2]. In this case, π electrons rotate along the Z-axis of the laboratory coordinates, while for the present case electrons rotate along the z-axis in molecular Cartesian coordinates. It should be noted that signals originated from the coherent ring currents prepared by linearly polarized ultrashort UV lasers are specific to the chiral molecule of interest.

scholarly journals Astrophysical relevance of the low-energy dipole strength of 206Pb

2018 ◽  
Vol 178 ◽  
pp. 04003
Author(s):  
A.P. Tonchev ◽  
N. Tsoneva ◽  
S. Goriely ◽  
C. Bhatia ◽  
C.W. Arnold ◽  
...  
Keyword(s):  
Excited States ◽  
Experimental Information ◽  
Neutron Separation Energy ◽  
Resonance Fluorescence ◽  
Photon Beams ◽  
Dipole Strength ◽  
Nuclear Resonance Fluorescence ◽  
Decay Widths ◽  
Linearly Polarized ◽  
Important Branch

The dipole strength of 206Pb was studied below the neutron separation energy using photon scattering experiments at the HIGS facility. Utilizing the technique of nuclear resonance fluorescence with 100% linearly-polarized photon beams, the spins, parities, branching ratios and decay widths of excited states in 206Pb from 4.9 - 8.1 MeV have been measured. The new experimental information is used to reliably predict the neutron capture cross section of 205Pb, an important branch point nucleus along the s-process path of nucleosynthesis.

scholarly journals DOUBLE-VALUEDNESS OF THE ELECTRON WAVEFUNCTION AND ROTATIONAL ZERO-POINT MOTION OF ELECTRONS IN RINGS

2010 ◽  
Vol 24 (21) ◽  
pp. 2201-2214 ◽  
Author(s):  
J. E. HIRSCH
Keyword(s):  
Angular Momentum ◽  
Aromatic Ring ◽  
Orbital Angular Momentum ◽  
Ground State ◽  
Spin Current ◽  
Zero Point ◽  
Persistent Currents ◽  
Ring Molecules ◽  
Point Motion ◽  
Electron Wavefunction

I propose that the phase of an electron's wavefunction changes by π when the electron goes around a loop maintaining phase coherence. Equivalently, that the minimum orbital angular momentum of an electron in a ring is ℏ/2 rather than zero as generally assumed, hence, that the electron in a ring has azimuthal zero point motion. This proposal implies that a spin current exists in the ground state of aromatic ring molecules and suggests an explanation for the ubiquitousness of persistent currents observed in mesoscopic rings.

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