scholarly journals Asymmetric Photolysis of 2-Phenylcycloalkanones with Circularly Polarized Light: A Kinetic Model for Magnetic Field Effects

2002 ◽  
Vol 75 (6) ◽  
pp. 1223-1233 ◽  
Author(s):  
Shigeru Kohtani ◽  
Masahide Sugiyama ◽  
Yoshihisa Fujiwara ◽  
Yoshifumi Tanimoto ◽  
Ryoichi Nakagaki
Keyword(s):  
Magnetic Field ◽  
Kinetic Model ◽  
Polarized Light ◽  
Magnetic Field Effects ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Field Effects ◽  
Asymmetric Photolysis

scholarly journals Optical Transition Rates in a Cylindrical Quantum Wire with Parabolic and Inverse Parabolic Electric Confining Potentials in a Magnetic Field

2021 ◽  
Author(s):  
Moletlanyi Tshipa ◽  
Monkami Masale
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Polarized Light ◽  
Electronic States ◽  
Dipole Approximation ◽  
Transition Rates ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Quantum Numbers ◽  
Parabolic Potential

Abstract Electron transition rates due to interaction with circularly polarized light incident along the axis of a free-standing solid cylindrical nanowire are evaluated in the dipole approximation. The electric confinement potential of the nanowire is modeled as a superposition of two parts, in general, of different strengths; viz; parabolic and inverse parabolic in the radial distance. Additional confinement of the charge carriers is through the vector potential of the axial applied magnetic field. In systems with cylindrical symmetry, the electronic states are in part characterized by azimuthal quantum numbers: m=0, ±1, ±2,..., which in the absence of the axial applied magnetic field are doubly degenerate. In the dipole approximation and for circularly polarized light the selection rules are such that optical transitions are allowed between electronic states whose azimuthal quantum numbers differ by unity. Transition rates are characterized by peaks whenever the energy of the incident electromagnetic radiation matches transition energies for states between which transitions occur. The parabolic potential blue shifts peak of transition rates while the inverse parabolic potential redshifts the peaks. Results also indicate that transition rates are higher in nanowires of smaller radii. The homogeneous magnetic field lifts the double-degeneracies of electrons with opposite angular momenta, which leads to the emergence of two branches of the transition rates.

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.

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

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