scholarly journals Integration of Global Ring Currents Using the Ampére-Maxwell Law

2021 ◽  
Author(s):  
Raphael Berger ◽  
Maria Dimitrova ◽  
Rinat Nasibullin ◽  
Rashid R. Valiev ◽  
Dage Sundholm
Keyword(s):  
Ring Current ◽  
Magnetic Shielding ◽  
Ring Currents ◽  
Shielding Tensor

Magnetically induced ring current are calculated from the magnetic shielding tensor by employing the Ampére-Maxwell law. The feasibility of the method is demonstrated by integrating the zz component of the...

scholarly journals Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 861-872
Author(s):  
Peter B. Karadakov
Keyword(s):  
Ring Current ◽  
Magnetic Shielding ◽  
Ring Strain ◽  
Carbon Ring ◽  
Plane Component ◽  
Out Of Plane ◽  
Contour Plots ◽  
Shielding Tensor ◽  
Planar Geometries

Bonding and aromaticity in the bowl-shaped C5v and planar D5h geometries of corannulene and the planar D6h geometry of coronene are investigated using 3D isosurfaces and 2D contour plots of the isotropic magnetic shielding σiso(r) and, for planar geometries, of the out-of-plane component of the shielding tensor σzz(r). Corannulene and coronene both feature conjoined shielded “doughnuts” around a peripheral six-membered carbon ring, suggesting strong bonding interactions and aromatic stability; a deshielded region inside the hub ring of corannulene indicates that this ring is antiaromatic, more so in planar corannulene. The switch from the planar to the bowl-shaped geometry of corannulene is shown to enhance both bonding and the local aromaticities of the five- and six-membered rings; these factors, in addition to ring strain reduction, favour the bowl-shaped geometry. The most and least shielded bonds in both corannulene and coronene turn out to be the spoke and hub bonds, respectively. The higher π electron activity over spoke bonds in planar corannulene and coronene is supported by σzz(r) contour plots in planes 1 Å above the respective molecular planes; these findings about spoke bonds are somewhat unexpected, given that ring current studies indicate next to no currents over spoke bonds.

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.

Probing solid iminobis(diorganophosphine chalcogenide) systems with multinuclear magnetic resonance

2009 ◽  
Vol 87 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Bryan A Demko ◽  
Roderick E Wasylishen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magnetic Shielding ◽  
Chemical Shift Tensors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Shielding Tensor ◽  
Nuclear Magnetic Shielding Tensors ◽  
Nuclear Magnetic

A 31P and 77Se solid-state NMR investigation of the iminobis(diorganophosphine chalcogenide) HN(R2PE)2 (R = Ph,iPr; E = O, S, Se) systems is presented. The NMR results are discussed in terms of the known HN(R2PE)2 structures available from X-ray crystallography. The phosphorus chemical shift tensors are found to be sensitive to the nature of the alkyl and chalcogen substituents. The nature of the R group also influences the selenium chemical shift tensors of HN(R2PSe)2 (R = Ph, iPr), which are shown to be sensitive to hydrogen bonding in the dimer structure of HN(Ph2PSe)2 and to the presence of disorder in the case of HN(iPr2PSe)2. Scalar relativistic ZORA DFT nuclear magnetic shielding tensor calculations were performed yielding the orientations of the corresponding chemical shift tensors. A theoretical investigation into the effect of the E-P···P-E “torsion” angle on the phosphorus and selenium chemical shift tensors of a truncated HN(Me2PSe)2 system indicates that the electronic effect of the alkyl group on the respective nuclear magnetic shielding tensors are more important than the steric effect of the E-P···P-E torsion angle.Key words: iminobis(diorganophosphine chalcogenide), solid-state NMR, 31P NMR, 77Se NMR, ZORA DFT.

Proton Magnetic Shielding Tensor in Liquid Water

2002 ◽  
Vol 124 (40) ◽  
pp. 12031-12041 ◽  
Author(s):  
Kristofer Modig ◽  
Bertil Halle
Keyword(s):  
Liquid Water ◽  
Magnetic Shielding ◽  
Shielding Tensor

The making of ring currents

2016 ◽  
Vol 18 (17) ◽  
pp. 11800-11812 ◽  
Author(s):  
Guglielmo Monaco ◽  
Riccardo Zanasi
Keyword(s):  
Ring Current ◽  
Ring Currents

The π-electron diatropic ring current emerging throughout the trimerization of acetylene to benzene.

Nuclear magnetic shielding and chirality. I. The shielding tensor of Xe interacting with Ne helices

2003 ◽  
Vol 119 (5) ◽  
pp. 2685-2690 ◽  
Author(s):  
Devin N. Sears ◽  
Cynthia J. Jameson ◽  
Robert A. Harris
Keyword(s):  
Magnetic Shielding ◽  
Shielding Tensor ◽  
Nuclear Magnetic
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