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.

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.

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 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.

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.

The usefulness of high index low symmetry zone axes for holz line analysis

1987 ◽  
Vol 45 ◽  
pp. 384-385
Author(s):  
C. M. Sung ◽  
D. B. Williams
Keyword(s):  
Lattice Parameter ◽  
High Order ◽  
Zone Axis ◽  
High Index ◽  
High Symmetry ◽  
Second Phases ◽  
Line Patterns ◽  
Low Symmetry ◽  
Line Analysis

Researchers have tended to use high symmetry zone axes (e.g. <111> <114>) for High Order Laue Zone (HOLZ) line analysis since Jones et al reported the origin of HOLZ lines and described some of their applications. But it is not always easy to find HOLZ lines from a specific high symmetry zone axis during microscope operation, especially from second phases on a scale of tens of nanometers. Therefore it would be very convenient if we can use HOLZ lines from low symmetry zone axes and simulate these patterns in order to measure lattice parameter changes through HOLZ line shifts. HOLZ patterns of high index low symmetry zone axes are shown in Fig. 1, which were obtained from pure Al at -186°C using a double tilt cooling holder. Their corresponding simulated HOLZ line patterns are shown along with ten other low symmetry orientations in Fig. 2. The simulations were based upon kinematical diffraction conditions.

Frozen-Orbital Analysis of the Excited States of Metal Complexes in High Symmetry: OhCase

1996 ◽  
Vol 100 (39) ◽  
pp. 15753-15759 ◽  
Author(s):  
Hiromi Nakai ◽  
Hiroshi Morita ◽  
Hiroshi Nakatsuji
Keyword(s):  
Metal Complexes ◽  
Excited States ◽  
High Symmetry ◽  
Orbital Analysis

An X-ray diffraction study of AgNbO3 and comparison with NaNbO3

1999 ◽  
Vol 14 (4) ◽  
pp. 253-257 ◽  
Author(s):  
C. N. W. Darlington
Keyword(s):  
Diffraction Pattern ◽  
Figure Of Merit ◽  
Parent Phase ◽  
Incident Beam ◽  
Large Error ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Beam Focusing ◽  
Low Symmetry

The powder diffraction pattern of the perovskite AgNbO3 has been measured using CuKα1 radiation with an incident beam focusing monochromator to eliminate the Kα2 component. Indexing the pattern shows that the multipartite cell is 2×2×4 times that of the pseudocubic subcell. Comparison is made with the diffraction pattern of NaNbO3, which has a similar multipartite unit cell. There are strong similarities, but close inspection shows that the structures are not isomorphous. The paper concludes with a discussion of the figure of merit FN for pseudosymmetric structures. It is suggested that two figures of merit be reported. The first should be the standard one using either all measured reflections or just the first 30. The proposed second figure of merit does not include any superlattice reflections. These superlattice reflections tend to be very weak, resulting in a low completeness factor and relatively large error in the measurement of their position. This effect produces an unrealistically low value of the standard figure of merit. By including only “main” reflections, i.e., those reflections that are common to both the low-symmetry and high-symmetry parent phase (if it exists), a much better estimate of the quality of the fitting of the measured diffraction pattern is obtained.

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