Measurement Error of Interferometers with Diffraction Reference Wave

Technical Physics - An experimental setup and results on aberration of sources of a reference spherical wave (SRSW) based on a single-mode optical fiber with a subwavelength output aperture...     

High-Power Microwave Photodiodes Based on MBE-Grown InAlAs/InGaAs Heterostructures

Technical Physics - The design and fabrication technology of high-power Schottky-barrier microwave mesa photodiodes from 10 to 40 μm in diameter back-illuminated through the substrate are...     

Complexing of tellurium-doped gallium arsenide in gas-phase epitaxy

The effect of the conditions of gas-phase epitaxy on complexing in tellurium-doped layers of gallium arsenide is studied. Measurements of the intensities of the corresponding photoluminescence lines were used to estimate the concentration of optically-active complexes. A correlation was found between the processes involved in complexing, the growth velocity, and impurity trapping in the layers. The determining role of the surface structure in the formation of complexes, including impurity atoms, is demonstrated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 96–100, February, 1985.     

QSPR Modeling of Complex Stability by Correlation Weighing of the Topological and Chemical Invariants of Molecular Graphs

The concept of modeling of the complex stability based on optimization of the correlation weights of the nearest neighborhood codes (NNC), the hydrogen bond index (HBI), and the cyclicity code (CC) is described. The NNC is a local topochemical invariant of a vertex of the molecular graph whose numerical value is a function of the total number and the composition of vertices adjacent to the given vertex. The HBI is a global chemical invariant of the molecular graph calculated from the number of oxygen and nitrogen atoms. The CC is a global topological invariant of the graph equal to the number of rings present in the ligand structure. The statistical characteristics of the best model of the stability constants of the complexes are as follows: n = 75, r = 0.9738, s = 0.457, F = 1337 (training sample); n = 75, r = 0.9795, s = 0.461, F = 1724 (test sample).     

Structure and Absorption Spectra of Polyhydroquinones

Radical polymerization of hydroquinone was studied in an aqueous medium. Black polymers of low molecular weight (up to 1500 Da), poorly soluble in water and alcohols, are formed. Ab initio calculations of the steric and electronic structure and vibrational and electronic spectra of molecules containing 1 to 5 hydroquinone units were performed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 662–668.Original Russian Text Copyright © 2005 by Zagorskii, Kalnin’sh, Toropov.     

Excitonic Emission in van der Waals Nanotubes of Transition Metal Dichalcogenides

Nanotubes (NTs) of transition metal dichalcogenides (TMDs), were first synthesized more than a quarter of a century ago; nevertheless, many of their optical properties have so far remained basically unknown. Herein, the state of the art in the knowledge of the optical properties of TMD NTs is presented. First, general properties of multilayered crystals are evaluated, and available data on related NTs are analyzed. Then, the technology for the formation and the structural characteristics of NTs are represented, focusing on the structures synthesized by chemical transport reaction. The core of this work is the presentation of the ability of synthesized TMD NTs to emit bright photoluminescence (PL), which has been discovered recently. By means of micro‐PL spectroscopy of individual tubes, we show that excitonic transitions relevant to both direct and indirect band gaps contribute to the emission spectra of the NTs despite having the dozens of monolayers in their walls. The performance of the tubes as efficient optical resonators is highlighted, where confined optical modes strongly affect the emission. Finally, a brief conclusion is presented, along with an outlook of the future studies of this novel radiative member of the NTs family, which have unique potential for different nanophotonics applications.     

Fourier Transform Limited Linewidth of Optical Transitions in Single SiV Centers in “Adamantane” Nanodiamonds

JETP Letters - Silicon-vacancy (SiV) color centers in diamond offer a promising system for quantum information applications owing to their intense narrowband emission and optically detectable spin...     

The system of self-consistent QSPR-models for refractive index of polymers

Structural Chemistry - Quantitative structure–property/activity relationships (QSPRs/QSARs) are a component of modern natural science. The system of self-consistent models is a specific...