Исследование диэлектрических функций слоя наночастиц Ag на кремнии с помощью спектроэллипсометрии и спектрофотометрии

An investigation of the optical characteristics of a layer of Ag nanoparticles deposited from an AgNO3 solution on the surface of single-crystal Si is presented. The measurements were carried out using spectroscopic ellipsometry and spectrophotometry at the same tilt angle and sample probe location in a wide spectral range from 200 to 1700 nm. From the obtained experimental data, the parameters of the Drude-Lorentz model and the complex dielectric function were determined, which was compared with the pseudo-dielectric function. Both dependences revealed resonances of a bulk plasmon near the energy E = 3.8 eV, while a localized plasmon was detected in the pseudo-dielectric function at E = 1.65 eV, and in the dielectric function at E = 1.84 eV.

Drude–Lorentz Model for Optical Properties of Photoexcited Transition Metals under Electron–Phonon Nonequilibrium

Evaluating the optical properties of matter under the action of ultrafast light is crucial in modeling laser–surface interaction and interpreting laser processing experiments. We report optimized coefficients for the Drude–Lorentz model describing the permittivity of several transition metals (Cr, W, Ti, Fe, Au, and Ni) under electron–phonon nonequilibrium, with electrons heated up to 30,000 K and the lattice staying cold at 300 K. A Basin-hopping algorithm is used to fit the Drude–Lorentz model to the nonequilibrium permittivity calculated using ab initio methods. The fitting coefficients are provided and can be easily inserted into any calculation requiring the optical response of the metals during ultrafast irradiation. Moreover, our results shed light on the electronic structure modifications and the relative contributions of intraband and interband optical transitions at high electron temperatures corresponding to the laser excitation fluence used for surface nanostructuring.

Rhodium (III) Oxide or Rhodium Sesquioxide (Rh2O3) and Rhodium (IV) Oxide (RhO2) Effect on the Stop Growth of Cancer Cells, Tissues and Tumors under Synchrotron and Synchrocyclotron Radiations

In the current research, Rhodium (III) Oxide or Rhodium Sesquioxide (Rh2O3) and Rhodium (IV) Oxide (RhO2) effect on the stop growth of cancer cells, tissues and tumors under synchrotron and synchrocyclotron radiations. Is investigated. The calculation of thickness and optical constants of Rhodium (III) Oxide or Rhodium Sesquioxide (Rh2O3) and Rhodium (IV) Oxide (RhO2) Rhodium (III) Oxide or Rhodium Sesquioxide (Rh2O3) and Rhodium (IV) Oxide (RhO2) effect on the stop growth of cancer cells, tissues and tumors under synchrotron and synchrocyclotron radiations produced using sol–gel method over glassy medium through a single reflection spectrum is presented. To obtain an appropriate fit for reflection spectrum, the classic Drude–Lorentz model for parametric di–electric function is used. The best fitting parameters are determined to simulate the reflection spectrum using Lovenberg–Marquardt optimization method. The simulated reflectivity from the derived optical constants and thickness are in good agreement with experimental results. Keywords: Rhodium (III) Oxide or Rhodium Sesquioxide (Rh2O3) and Rhodium (IV) Oxide (RhO2); Stop Growth; Cancer Cells; Tissues and Tumors; Synchrotron and Synchrocyclotron Radiations

Catalytic Effectiveness of Synchrotron and Synchrocyclotron Radiations on Osmium Dioxide (OsO2) and Osmium Tetroxide (OsO4) Nano Capsules Delivery in DNA/RNA of Cancer Cells

In the current research, catalytic effectiveness of synchrotron and synchrocyclotron radiations on Osmium Dioxide (OsO2) and Osmium Tetroxide (OsO4) nano capsules delivery in DNA/RNA of cancer cells is investigated. The calculation of thickness and optical constants of Osmium Dioxide (OsO2) and Osmium Tetroxide (OsO4) catalytic effectiveness of synchrotron and synchrocyclotron radiations on Osmium Dioxide (OsO2) and Osmium Tetroxide (OsO4) nano capsules delivery in DNA/RNA of cancer cells produced using sol-gel method over glassy medium through a single reflection spectrum is presented. To obtain an appropriate fit for reflection spectrum, the classic Drudge-Lorentz model for parametric di–electric function is used. The best fitting parameters are determined to simulate the reflection spectrum using Levenberg-Marquardt optimization method. The simulated reflectivity from the derived optical constants and thickness are in good agreement with experimental results. Keywords: Catalytic Effectiveness; Synchrotron and Synchrocyclotron Radiations; Osmium Dioxide (OsO2) and Osmium Tetroxide (OsO4) Nano Capsules; Delivery; DNA/RNA; Cancer Cells

Unusually Large Exciton Binding Energy In Multilayered 2H-MoTe2

Although large exciton binding energies of typically 0.6–1.0 eV are observed for monolayer transition metal dichalcogenides (TMDs) owing to strong Coulomb interaction, multilayered TMDs yield relatively low exciton binding energies owing to increased dielectric screening. Recently, the ideal carrier-multiplication threshold energy of twice the bandgap has been realized in multilayered semiconducting 2H-MoTe2 with a conversion efficiency of 99%, which suggests strong Coulomb interaction. However, the origin of strong Coulomb interaction in multilayered 2H-MoTe2, including the exciton binding energy, has not been elucidated to date. In this study, unusually large exciton binding energy is observed through optical spectroscopy conducted on CVD-grown 2H-MoTe2. To extract exciton binding energy, the optical conductivity is fitted using the Lorentz model to describe the exciton peaks and the Tauc–Lorentz model to describe the indirect and direct bandgaps. The exciton binding energy of 4 nm thick multilayered 2H-MoTe2 is approximately 300 meV, which is unusually large by one order of magnitude when compared with other multilayered TMD semiconductors such as 2H-MoS2 or 2H-MoSe2. This finding is interpreted in terms of small exciton radius based on the 2D Rydberg model. The exciton radius of multilayered 2H-MoTe2 resembles that of monolayer 2H-MoTe2, whereas those of multilayered 2H-MoS2 and 2H-MoSe2 are large when compared with monolayer 2H-MoS2 and 2H-MoSe2. From the large exciton binding energy in multilayered 2H-MoTe2, it is expected to realize the future applications such as room-temperature and high-temperature polariton lasing.

Correlations obtained from optical spectra of Fe-pnictides using an extended Drude-Lorentz model

We introduce an analysis model, an extended Drude–Lorentz model, and apply it to Fe-pnictide systems to extract their electron–boson spectral density functions (or correlation spectra). The extended Drude–Lorentz model consists of an extended Drude mode for describing correlated charge carriers and Lorentz modes for interband transitions. The extended Drude mode can be obtained by a reverse process starting from the electron–boson spectral density function and extending to the optical self-energy, and eventually, to the optical conductivity. Using the extended Drude–Lorentz model, we obtained the electron–boson spectral density functions of K-doped BaFe 2 As 2 (Ba-122) at four different doping levels. We discuss the doping-dependent properties of the electron–boson spectral density function of K-doped Ba-122. We also can include pseudogap effects in the model using this new approach. Therefore, this new approach is very helpful for understanding and analyzing measured optical spectra of strongly correlation electron systems, including high-temperature superconductors (cuprates and Fe-pnictides).

STUDYING THE INTERCONNECTION OF FOOD, ENERGY AND WATER RESOURCES USING THE THREE-SECTORAL LORENTZ MODEL

The work is devoted to the problem of creating new methods for complex modeling and risk management, which will allow to study synergistic interactions between sources of risks of various origins under conditions of uncertainty. The paper proposes an approach to the study of the relationship between food, water and energy resources using the three-sectoral Lorenz model, combining in a single structure similarly described sectors of the economy, each of which is considered in terms of the productivity level, the workplaces number and the structural disturbances level. As a mathematical modeling result, the conditions of the deterministic chaos origin in the minimum economic development model were determined and possible reasons of the global economy growing vulnerability to small changes in management parameters were identified. The problem of determining effective controls for minimizing the total structural violations on selected time interval is considered. As a result of model experiments, the trajectories of control parameters changes were determined, which make it possible to reduce the structural violations number. This is achieved through changes in the ratio of supply and demand levels for products, demand and supply for workplaces creation. The influence of random perturbations on the deterministic attractors stochastic deformation of the Lorentz model is considered. It is shown that, under random perturbations, the trajectories of the stochastic system leave a deterministic attractor and form around it a certain bundle with the corresponding probabilistic distribution. The further model complicating possibility by taking into account other sectors of the economy using the Lorenz model in a complex form is considered. In this case the task of studying n sectors of economy is reduced to considering the behavior of an ensemble of n coupled oscillators that generate oscillations with frequencies ωn, respectively. Collective synchronization of oscillator data can be investigated using Kuramoto’s model. The problem of managing socio-economic development under the chaotic modes origin conditions is reduced for a complex model to controlling the frequency of a nonzero mean field generated by coupled oscillators.

Application of the dynamic Lorentz model to modeling the motion of a rigid body

A qualitative research of the field of phase trajectories of the system of dynamic equations of an absolutely rigid body was carried out, moving around the selected pole under the influence of gyroscopic, dissipative forces and Coriolis inertia forces. The equations of body motion are reduced to a dynamical system generating a Lorentz attractor. Under parametric constraints imposed on the equations of a dynamical system, the structure of its phase trajectories is described depending on the values of the system parameters.