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The development of a photoelectrical hydrogen sensor without sensor element heating is presented. For the sensitive element of the hydrogen sensor the Pd/n-InP (Schottkie diode) and Pd/oxide/InP (met-alinsulator-semiconductor) structures were developed and investigations of the photovoltage and the photocurrent of the structures depending on the hydrogen concentration in the range 0.1–100 vol.% in a nitrogen-hydrogen gas mixture were carried out. It is shown that the photovoltage and photocurrent decay rate and the hydrogen concentration are exponentially related to each other. The laboratory samples of sensor for hydrogen determination in the range 100–30000 ppm which able to operate at room temperature with response rate of 1–2 s are developed.

A combined approach has been developed for the identification and determination of quinolone antibiotics in pharmaceuticals using solid-phase fluorescence digital colorimetry and chemometric analysis. The eigen fluorescence of quinolones and quinolone-sensitized fluorescence of europium(III) have been studied on various matrices. The paper proposes a test-system consisting of four indicator zones. Under irradiation with ultraviolet light (365 nm) of quinolone solutions applied to the indicator zones of test systems, there are observed blue fluorescence on cellulose paper (CP) and plates for high performance thin layer chromatography (HPTLC) and pink (CP–Eu, HPTLC–Eu) fluorescence. The measurement of the fluorescence intensity on the surface of the matrices has been carried out using a smartphone. The possibility of using chemometric analysis, which makes it possible to reduce the analysis time and visualize research data, has been shown. The data array was processed by principal component methods, hierarchical cluster analysis, and the kmean method using the XLSTAT software. The identification and assessment of the quantitative content of quinolone antibiotics in tablet forms have been carried out using chemometric analysis. The calibration dependences in the РСА and k-mean methods have a logarithmic form in the ranges of the determined concentrations of 0.5–250 μg/ml (R2 ≥ 0.98). A technique for the determination of fluoroquinolones in pharmaceuticals has been proposed. The relative standard deviation does not exceed 0.09.

The lidar equation for Raman scattering of light by hydrogen fluoride molecules is solved in order to select the laser wavelength and lidar parameters and to obtain a minimum time for measuring the Raman scattering signal corresponding to the minimum concentration of the molecules at the TLV (threshold limit value) level. It is shown that the time for measuring a concentration of 1014 cm–3 HF molecules by this lidar at a laser wavelength of 405 nm and altitude in the 100–1500 m range lies within an interval of 0.04–14.4 s.

An ellipsometric method is used to study the optical properties of unoxidized surfaces of polycrystalline ytterbium film in the spectral range of 0.4–2.6 mm. The measured refractive indices and absorption coeffi cient of the film are used to calculate the dispersion dependences of the optical conductivity σ reflectivity R, the imaginary and real parts of the dielectric constant e1 and e2, and the characteristic electron energy loss functions Im(e–1). The infrared measurements are used in a two-band model for the conductivity to calculate the electronic characteristics of ytterbium in the solid and liquid states.

The formation mechanisms of the zero-phonon line optical center at 580 nm (H19 center) in photoluminescence spectra of irradiated natural diamonds and those deposited from the vapor phase were studied after their hightemperature vacuum annealing. The photoluminescence band intensity of the H19 center was shown to increase exponentially as the annealing temperature increased. Temperature dependences of photoluminescence spectra and local mechanical stress effects on the position and full width at half-height of the 580-nm zero-phonon line optical peak led to the conclusion that the H19 optical center was a complex intrinsic vacancy defect. The work was financially supported by the Russian Science Foundation (Project 18-72-00076). Изучены механизмы формирования оптического центра с бесфононной линией (БФЛ) на 580 нм (центр Н19), проявляющегося в спектрах фотолюминесценции (ФЛ) радиационно-модифицированных природных и осажденных из газовой фазы алмазов после их высокотемпературного отжига в вакууме. Показано, что амплитуда полосы ФЛ центра Н19 экспоненциально возрастает по мере повышения температуры отжига. Из исследований температурной зависимости спектров ФЛ и влияния локальных механических напряжений на положение и ширину на полувысоте пика БФЛ 580 нм сделан вывод, что оптический центр H19 является сложным собственным вакансионным дефектом.

We have studied the EPR of Mn2+ ions in three samples of cubic nano-ZnS made by different technologies and having different nanoparticle sizes. Manganese occurs in the samples as an uncontrolled impurity. The EPR spectra can be described by two components: the spectrum of the Mn2+ in a cubic environment (Mn2+(C)) with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, 0 b4 ≥ 3.5·10–4 cm–1; and the spectrum of the Mn2+ ion associated with a planar lattice stacking fault (Mn2+ (F)), with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, $$ {b}_2^0 $$ = (–36 ± 1)·10–4 cm–1. The ratio of the number of centers Mn2+(C)/Mn2+(F) is 2.1:1 for sample 1 and 1.7:1 for samples 2 and 3. Planar stacking faults are typical lattice faults for cubic nano-ZnS. EPR of the Mn2+ ions lets us monitor the presence of these ions.