scholarly journals Bridge-Mediated RET between Two Chiral Molecules

2021 ◽  
Vol 11 (3) ◽  
pp. 1012
Author(s):  
A Salam
Keyword(s):  
Magnetic Dipole ◽  
Electric Dipole ◽  
Quantum Electrodynamics ◽  
Resonance Energy Transfer ◽  
Golden Rule ◽  
Resonance Energy ◽  
Multipole Moment ◽  
Dipole Approximation ◽  
Chiral Molecules ◽  
The Matrix

Molecular quantum electrodynamics (QED) theory is employed to calculate the rate of resonance energy transfer (RET) between a donor, D, described by an electric dipole and quadrupole, and magnetic dipole coupling, and an identical acceptor molecule, A, that is mediated by a third body, T, which is otherwise inert. A single virtual photon propagates between D and T, and between T and A. Time-dependent perturbation theory is used to compute the matrix element, from which the transfer rate is evaluated using the Fermi golden rule. This extends previous studies that were limited to the electric dipole approximation only and admits the possibility of the exchange of excitation between a chiral emitter and absorber. Rate terms are computed for specific pure and mixed multipole-dependent contributions of D and A for both an oriented arrangement of the three particles and for the freely tumbling situation. Mixed multipole moment contributions, such as those involving electric–magnetic dipole or electric dipole–quadrupole coupling at one center, do not survive random orientational averaging. Interestingly, the mixed electric–magnetic dipole D and A rate term is non-vanishing and discriminatory, exhibiting a dependence on the chirality of the emitter and absorber, and is entirely retarded. It vanishes, however, if D and A are oriented perpendicularly to one another. Near- and far-zone asymptotes of isotropic contributions to the rate are also evaluated, demonstrating radiationless short-range transfer and inverse-square radiative exchange at very large separations.

scholarly journals The Unified Theory of Resonance Energy Transfer According to Molecular Quantum Electrodynamics

Atoms ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
A. Salam
Keyword(s):  
Perturbation Theory ◽  
Energy Transfer ◽  
Quantum Electrodynamics ◽  
Complex Refractive Index ◽  
Resonance Energy Transfer ◽  
Golden Rule ◽  
Resonance Energy ◽  
Microscopic Analysis ◽  
Pair Separation ◽  
Three Body

An overview is given of the molecular quantum electrodynamical (QED) theory of resonance energy transfer (RET). In this quantized radiation field description, RET arises from the exchange of a single virtual photon between excited donor and unexcited acceptor species. Diagrammatic time-dependent perturbation theory is employed to calculate the transfer matrix element, from which the migration rate is obtained via the Fermi golden rule. Rate formulae for oriented and isotropic systems hold for all pair separation distances, R, beyond wave function overlap. The two well-known mechanisms associated with migration of energy, namely the R−6 radiationless transfer rate due to Förster and the R−2 radiative exchange, correspond to near- and far-zone asymptotes of the general result. Discriminatory pair transfer rates are also presented. The influence of an environment is accounted for by invoking the polariton, which mediates exchange and by introducing a complex refractive index to describe local field and screening effects. This macroscopic treatment is compared and contrasted with a microscopic analysis in which the role of a neutral, polarizable and passive third-particle in mediating transfer of energy is considered. Three possible coupling mechanisms arise, each requiring summation over 24 time-ordered diagrams at fourth-order of perturbation theory with the total rate being a sum of two- and various three-body terms.

scholarly journals Rapid and Simple Detection of Ochratoxin A using Fluorescence Resonance Energy Transfer on Lateral Flow Immunoassay (FRET-LFI)

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 292
Author(s):  
Hyun-Kyung Oh ◽  
Hyou-Arm Joung ◽  
Minhyuk Jung ◽  
Hohjai Lee ◽  
Min-Gon Kim
Keyword(s):  
Energy Transfer ◽  
Ochratoxin A ◽  
Fluorescence Resonance Energy Transfer ◽  
Matrix Effect ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
The Matrix ◽  
Fluorescence Resonance

The detection of mycotoxins is crucial because of their toxicity in plants, animals, and humans. It is very important to determine whether food products are contaminated with mycotoxins such as ochratoxin A (OTA), as mycotoxins can survive heat treatments and hydrolysis. In this study, we designed a fluorescence resonance energy transfer (FRET)-based system that exploits antibody-antigen binding to detect mycotoxins more rapidly and easily than other currently available methods. In addition, we were able to effectively counteract the matrix effect in the sample by using a nitrocellulose membrane that enabled fluorescence measurement in coffee samples. The developed FRET on lateral flow immunoassay (FRET-LFI) system was used to detect OTA at a limit of detection (LOD) of 0.64 ng∙mL−1, and the test can be completed in only 30 min. Moreover, OTA in coffee samples was successfully detected at a LOD of 0.88 ng∙mL−1, overcoming the matrix effect, owing to the chromatographic properties of the capillary force of the membrane. We believe that the developed system can be used as a powerful tool for the sensitive diagnosis of harmful substances such as mycotoxins and pesticides for environmental and food quality control monitoring.

scholarly journals Elastic Photon Scattering on Hydrogenic Atoms near Resonances

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 12 ◽  
Author(s):  
Dmitrii Samoilenko ◽  
Andrey Volotka ◽  
Stephan Fritzsche
Keyword(s):  
Electric Dipole ◽  
Quantum Electrodynamics ◽  
Rayleigh Scattering ◽  
Ion Beam ◽  
Scattered Light ◽  
Heavy Ion ◽  
Dipole Approximation ◽  
Degree Of Polarization ◽  
Relativistic Variant ◽  
Resonance Transitions

Scattering of light on relativistic heavy ion beams is widely used for characterizing and tuning the properties of both the light and the ion beam. Its elastic component—Rayleigh scattering—is investigated in this work for photon energies close to certain electronic transitions because of its potential usage in the Gamma Factory initiative at CERN. The angle-differential cross-section, as well as the degree of polarization of the scattered light are investigated for the cases of 1 s − 2 p 1 / 2 and 1 s − 2 p 3 / 2 resonance transitions in H-like lead ions. In order to gauge the validity and uncertainty of frequently used approximations, we compare different methods. In particular, rigorous quantum electrodynamics calculations are compared with the resonant electric-dipole approximation evaluated within the relativistic and nonrelativistic formalisms. For better understanding of the origin of the approximation, the commonly used theoretical approach is explained here in detail. We find that in most cases, the nonrelativistic resonant electric-dipole approximation fails to describe the properties of the scattered light. At the same time, its relativistic variant agrees with the rigorous treatment within a level of 10% to 20%. These findings are essential for the design of an experimental setup exploiting the scattering process, as well as for the determination of the scattered light properties.

scholarly journals Broadened Angle-Insensitive Near-Perfect Absorber Based on Mie Resonances in Amorphous Silicon Metasurface

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1733 ◽  
Author(s):  
Jiangnan Si ◽  
Shuang Liu ◽  
Weiji Yang ◽  
Xuanyi Yu ◽  
Jialin Zhang ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Magnetic Dipole ◽  
Electric Dipole ◽  
Dipole Approximation ◽  
Reflection Coefficients ◽  
Perfect Absorber ◽  
Enhanced Absorption ◽  
Transmission And Reflection Coefficients ◽  
Potential Applicability ◽  
Transmission And Reflection

A broadband near-perfect absorber is analyzed by an amorphous silicon (a-Si) hook shaped nanostructure metasurface. The transmission and reflection coefficients of the metasurface are investigated in the point electric and magnetic dipole approximation. By combining square and semicircle nanostructures, the effective polarizabilities of the a-Si metasurface calculated based on discrete dipole approximation (DDA) exhibit broadened peaks of electric dipole (ED) and magnetic dipole (MD) Mie resonances. The optical spectra of the metasurface are simulated with different periods, in which suppressed transmission are shifted spectrally to overlap with each other, leading to broadened enhanced absorption induced by interference of ED and MD Mie resonances. The angle insensitive absorption of the metasurface arrives 95% in simulation and 85% in experiment in spectral range from 564 nm to 584 nm, which provides potential applicability in nano-photonic fields of energy harvesting and energy collection.

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