scholarly journals False Chirality, Absolute Enantioselection and CP Violation: Pierre Curie’s Legacy

2020 ◽  
Vol 6 (1) ◽  
pp. 5 ◽  
Author(s):  
Laurence D. Barron
Keyword(s):  
Magnetic Fields ◽  
Cp Violation ◽  
Enantiomeric Excess ◽  
Polarized Light ◽  
Racemic Mixture ◽  
Circularly Polarized Light ◽  
Fundamental Symmetry ◽  
Electric And Magnetic Fields ◽  
Pierre Curie ◽  
Far From Equilibrium

The 1884 suggestion of Pierre Curie (1859–1906) that the type of dissymmetry shown by collinear electric and magnetic fields may induce an enantiomeric excess, in a chemical reaction that would otherwise produce a racemic mixture, is explored in the context of fundamental symmetry arguments. Curie’s arrangement exhibits false chirality (time-noninvariant enantiomorphism), and so it may not induce absolute enantioselection (ae) in a process that has reached thermodynamic equilibrium, since it does not lift the degeneracy of chiral enantiomers. However, it may do so in far-from-equilibrium processes via a breakdown in microscopic reversibility analogous to that observed in elementary particle processes under the influence of CP violation, the associated force possessing false chirality with respect to CP enantiomorphism. In contrast, an influence like circularly polarized light exhibiting true chirality (time-invariant enantiomorphism) lifts the degeneracy of enantiomers, and so may induce ae in all circumstances. Although to date, ae has not been observed under the influence of Curie’s arrangement of collinear electric and magnetic fields, it is argued that two different experiments have now demonstrated ae under a falsely chiral influence in systems far from equilibrium, namely in a spinning sample under a gravitational field, and in the separation of enantiomers at a ferromagnetic surface.

Graphene nanoribbons in criss-crossed electric and magnetic fields

2010 ◽  
Vol 368 (1932) ◽  
pp. 5431-5443 ◽  
Author(s):  
Oleksiy Roslyak ◽  
Godfrey Gumbs ◽  
Danhong Huang
Keyword(s):  
Magnetic Fields ◽  
Energy Range ◽  
Bound States ◽  
Graphene Nanoribbons ◽  
Strong Electric Field ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Electric And Magnetic Fields ◽  
Electron Transport Properties ◽  
Electrically Enhanced

Graphene nanoribbons (GNRs) in mutually perpendicular electric and magnetic fields are shown to exhibit dramatic changes in their band structure and electron-transport properties. A strong electric field across the ribbon induces multiple chiral Dirac points, closing the semiconducting gap in armchair GNRs. A perpendicular magnetic field induces partially formed Landau levels as well as dispersive surface-bound states. Each of the applied fields on its own preserves the even symmetry E k = E − k of the sub-band dispersion. When applied together, they reverse the dispersion parity to be odd, which gives E e, k =− E h,− k , and mix the electron and hole sub-bands within the energy range corresponding to the change in potential across the ribbon. This leads to oscillations of the ballistic conductance within this energy range. The broken time-reversal symmetry provides dichroism in the absorption of the circularly polarized light. As a consequence, one can observe electrically enhanced Faraday rotation, since the edges of the ribbon provide formation of the substantial density of states.

scholarly journals Predominantly left-handed circular polarization in comets: Does it indicate L-enantiomeric excess in cometary organics?

2008 ◽  
Vol 4 (S251) ◽  
pp. 311-312 ◽  
Author(s):  
V. Rosenbush ◽  
N. Kiselev ◽  
L. Kolokolova
Keyword(s):  
Light Scattering ◽  
Circular Polarization ◽  
Enantiomeric Excess ◽  
Polarized Light ◽  
Optically Active ◽  
Active Materials ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Cometary Dust ◽  
Left Handed

AbstractPolarimetric observations demonstrated that all comets with significant values of circular polarization show predominantly left–handed circularly polarized light. We discuss the presence of homochiral organics in cometary materials as a source of the observed circular polarization. We have studied the effect of chirality on light–scattering properties of cometary dust considering particles that possess optical activity. Our investigations show that the cometary dust may include optically active materials which can be prebiological homochiral organics.

scholarly journals Dynamic induction of enantiomeric excess from a prochiral azobenzene dimer under circularly polarized light

2015 ◽  
Vol 6 (2) ◽  
pp. 973-980 ◽  
Author(s):  
K. Rijeesh ◽  
P. K. Hashim ◽  
Shin-ichiro Noro ◽  
Nobuyuki Tamaoki
Keyword(s):  
Enantiomeric Excess ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Simultaneous Induction

We demonstrate the simultaneous induction of chirality and enantiomeric excess from a prochiral azobenzene dimerviaa chiral regioisomer formedin situupon CPL irradiation.

scholarly journals Astronomical Sources of Circularly Polarized Light and Their Role in Determining Molecular Chirality on Earth

1985 ◽  
Vol 112 ◽  
pp. 171-175
Author(s):  
Ramon D. Wolstencroft
Keyword(s):  
Polarized Light ◽  
Racemic Mixture ◽  
Relative Importance ◽  
Chiral Molecules ◽  
Direct Sunlight ◽  
Primitive Earth ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Chiral Selection ◽  
Asymmetric Photolysis

The major source of circularly polarized flux potentially capable of inducing asymmetric photolysis of a racemic mixture of chiral molecules on the primitive Earth is the daytime sky. The degree of circular polarization (q) depends on the slope and orientation of the local terrain which obscures part of the sky. After allowance for dilution by direct sunlight values of |q| range between about 10−4 and 10−5. The rates of (1) asymmetric photolysis, (2) chiral selection by the electro-weak process and (3) racemization are not yet well enough known for the relative importance of these processes to be definitely established.

Chiral-induced spin selectivity enables a room-temperature spin light-emitting diode

Science ◽  
2021 ◽  
Vol 371 (6534) ◽  
pp. 1129-1133
Author(s):  
Young-Hoon Kim ◽  
Yaxin Zhai ◽  
Haipeng Lu ◽  
Xin Pan ◽  
Chuanxiao Xiao ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Room Temperature ◽  
Light Emitting Diode ◽  
Polarized Light ◽  
Chiral Molecules ◽  
Circularly Polarized Light ◽  
Light Emitting ◽  
Circularly Polarized ◽  
Spin Polarized ◽  
Spin Led

In traditional optoelectronic approaches, control over spin, charge, and light requires the use of both electrical and magnetic fields. In a spin-polarized light-emitting diode (spin-LED), charges are injected, and circularly polarized light is emitted from spin-polarized carrier pairs. Typically, the injection of carriers occurs with the application of an electric field, whereas spin polarization can be achieved using an applied magnetic field or polarized ferromagnetic contacts. We used chiral-induced spin selectivity (CISS) to produce spin-polarized carriers and demonstrate a spin-LED that operates at room temperature without magnetic fields or ferromagnetic contacts. The CISS layer consists of oriented, self-assembled small chiral molecules within a layered organic-inorganic metal-halide hybrid semiconductor framework. The spin-LED achieves ±2.6% circularly polarized electroluminescence at room temperature.

Sign in / Sign up

Export Citation Format

Share Document