Impact of Adding -hexylamine to Nickel Metallophotoredox C-N Coupling to Form Diarylamines.

The mechanistic understanding of how alkylamines impact Ni-metallophotoredox C-N coupling to form diarylamines remains unclear. In this study, 12-alkylamines were evaluated as additives to determine their effects on the synthesis of diarylamines in a flow photochemical system. Notably, -hexylamine demonstrated the most significant promotional effect.

Light absorption by a planar array of spherical particles and a matrix in which they are embedded: statistical approach.

The fractions of light energy absorbed by a 2D array of spherical particles and the matrix in which they are embedded are determined. The solution is based on a volume integral equation and a statistical approach. The absorption coefficient of the array is found via the internal fields of the particles.

Optical characteristics of a monolayer of identical spherical particles in an absorbing host medium.

The problem of light interaction with a 2D ensemble of homogeneous spherical particles embedded into an unbounded homogeneous absorbing host medium is considered. Based on the statistical approach, the equations are derived to characterize optical response of such a system with taking into account multiple scattering of light. Numerical data are presented for the spectral behavior of coherent transmission and reflection, incoherent scattering, and absorption coefficients of thin dielectric, semiconductor, and metal films containing a monolayer of particles with various spatial organization.

Editorial: Special Issue "Liquid Crystals 2020".

This Special Issue, entitled "Liquid Crystals 2020", is a collection of ten original research papers, including two feature papers, on theoretical and experimental advanced studies of liquid crystal science and technology [...

Resonant absorption of light by a two-dimensional imperfect lattice of spherical particles.

The light absorption and scattering by an infinite two-dimensional array with an imperfect lattice of identical spherical particles is considered based on the statistical approach to a description of electromagnetic wave interaction with particulate media. Absorption resonances due to the coherent component of scattered light (zeroth order of diffraction) and resonances arising from the excitation of a flux of incoherently scattered light (higher diffraction orders) propagating at grazing angles to the array plane are studied. The dependence of absorption on the degree of positional ordering of particles is considered.

Non-Layered Gold-Silicon and All-Silicon Frequency-Selective Metasurfaces for Potential Mid-Infrared Sensing Applications.

We report simulations on the spectral behavior of non-layered gold-silicon and all-silicon frequency-selective metasurfaces in an asymmetric element configuration in the mid-infrared spectral window of 5-5.8 μm. The non-layered layout is experimentally feasible due to recent technological advances such as nano-imprint and nano-stencil lithography, and the spectral window was chosen due to the multitude of applications in sensing and imaging.

Incoherent component of light scattered by a monolayer of spherical particles: analysis of angular distribution and absorption of light.

We have derived an analytical solution for an incoherent component of light scattered by a normally illuminated monolayer of homogeneous spherical particles. It is based on the quasi-crystalline approximation of the theory of multiple scattering of waves as well as on the multipole expansion of electromagnetic fields and tensor Green's function in terms of vector spherical wave functions. We apply the solution to a description of scattering and absorption characteristics of partially ordered monolayers and monolayers with imperfect lattices.

Light scattering by ensemble of nonabsorbing correlated two-layered particles: specific feature for spectral dependence of extinction coefficient.

Scattering of light by an ensemble of nonabsorbing spherical concentric two-layered particles is considered. It has been shown that exponent of the power function describing the wavelength dependence of the extinction coefficient of the medium with subwavelength-sized particles can exceed considerably the value of 4, which takes place for the Rayleigh scattering. Spatial correlation of particles enhances this "anomalous" dependence on the wavelength.

Light scattering and morphology of the lymphocyte as applied to flow cytometry for distinguishing healthy and infected individuals.

A simple optical model of single lymphocytes with smooth and nonsmooth surfaces has been developed for healthy and infected individuals. The model can be used for rapid (in the real-time scale) solution of the inverse light-scattering problem on the basis of optical data measured by label-free flow cytometry. Light scattering patterns have been calculated for the model developed.

Retrieval of size and refractive index of spherical particles by multiangle light scattering: neural network method application.

A method to retrieve the radius and the relative refractive index of spherical homogeneous nonabsorbing particles by multiangle scattering is proposed. It is based on the formation of noise-resistant functionals of the scattered intensity, which are invariant with respect to the linear homogeneous transformations of an intensity-based signal and approximation of the retrieved parameters' dependence on the functionals by a feed-forward neural network. The neural network was trained by minimization of the mean squared relative error in the range of particle radii from 0.

Polarization properties of polymer-dispersed liquid-crystal film with small nematic droplets.

The polarization state of light transmitted through a polymer-dispersed liquid-crystal film with small, spherical, nonabsorbing, partially oriented nematic droplets is theoretically investigated. The model used is based on the effective medium approach. Scattering properties of a single droplet are described by the Rayleigh-Gans approximation.

Investigation of morphometric parameters for granulocytes and lymphocytes as applied to a solution of direct and inverse light-scattering problems.

Quantitative data on cell structure, shape, and size distribution are obtained by optical measurement of normal peripheral blood granulocytes and lymphocytes in a cell suspension. The cell nuclei are measured in situ. The distribution laws of the cell and nuclei sizes are estimated.

Order parameter of elongated liquid crystal droplets: the method of retrieval by the coherent transmittance data.

The inverse light-scattering problem for polymer dispersed liquid crystal film is considered. An optical method to retrieve the tensor order parameter of liquid crystal droplets arranged in a monolayer has been developed. The method is based on the measurement of coherent transmission coefficients of film at normal illumination and comparison with the results of the direct light-scattering problem solution.

Light propagation through a monolayer of discrete scatterers: analysis of coherent transmission and reflection coefficients.

An investigation of the coherent transmission and reflection coefficients of a monolayer of spherical scatterers as a function of their size, optical constants, and concentration is carried out. An analysis is performed of the quasi-crystalline approximation of the multiple-wave scattering theory and on the single-scattering approximation (SSA). The results permit determining the limits of applicability of the SSA to the layers with the partial ordering of spherical scatterers in analyzing the phases of the transmitted and the reflected waves.

Characterization of optically soft spheroidal particles by multiangle light-scattering data by use of the neural-networks method.

A method for evaluating the size of optically soft spheroidal particles by use of the angular structure of scattered light is proposed. It is based on the use of multilevel neural networks with a linear activation function. The retrieval errors of radius R of the equivolume sphere and aspect ratio e are investigated.