Appearance Of Spectral Bands Research Articles

Formation of Cluster Systems in Chaotic Condensed Media

Purpose. The study of cluster formation in a system of chaotically moving and interacting particles taking into account the Efimov effect and the "golden" section.Methods. Methods of mathematical modeling, quantum mechanics, a model of solid spheres, and a cluster model were used.Results. Within the framework of the proposed work, it is noted that in a three-particle system of particles, it is possible to form their spatial configuration in the form of a "golden" triangle, and in the case of an excited state of two particles, the third particle is far enough away from the other two, it is this configuration that corresponds to the conditions for the occurrence of the Efimov effect in a three-particle system.Based on the mathematical formalism of the description of self-organization processes in the work, it is shown that in chaotic environments within the framework of the Efimov model, with the involvement of the "golden" section in the mutual arrangement of three interacting particles, it is possible to form disk-shaped clusters containing a "magic" number of particles. In the structure of these clusters, the formation of quantum-dimensional regions in the form of a torus is possible. The parameters of such areas are defined.Conclusion. The described model of the formation and decay of disk-shaped clusters, taking into account the Efimov effect and the "golden" section rule, allows us, without resorting to a complex solution of equations in the three-body problem, to obtain important relations following from strict theories. The proposed approach implies the possibility of self-organization of clusters and the formation of quantum-dimensional regions in their structure, for example, in the form of a torus with a potential well, capable of capturing charged particles and determining their energy spectrum, as well as explaining the appearance of spectral bands in the IR spectra of substances.The proposed approach may be of practical importance, for example, for predicting the IR spectra of liquids, the presence of quantum dots in liquids with a wide spectrum of excitation from UV to IR radiation.

Характерные особенности низкочастотной области инфракрасных спектров и кластерная модель строения жидкостей

The results of experimental and theoretical studies of the low-frequency region of infrared spectra and Raman scattering spectra in liquid cyclic hydrocarbons (arenes) and their halogen-substituted ones are analyzed. The results of experimental studies of 13 liquids in the range 20–700 cm–1 using a high-resolution all-wavelength vacuum Fourier spectrometer (Bruker IFS 125 HR) are presented. It is shown that the appearance of spectral bands in the low-frequency region (the region of the “boson” peak) of the infrared spectra of liquids is due to the formation and decay of cluster formations in the structure of the liquid.

Antibacterial and Energy Gap Correlation of PVA/SA Biofilms Doped With Selenium Nanoparticles

Polymeric thin biofilms of polyvinyl alcohol (PVA)/sodium alginate (SA) doped with a different mass fraction of synthesized selenium nanoparticles were successfully synthesized using traditional solution casting routine. Obtained samples were studied for their structural variations using Fourier transform infrared (FT-IR), and ultravilot/visible (UV/Vis.) spectroscopy. FT-IR spectral data reveals the appearance of spectral bands characterized the functional groups of both PVA and SA structural units in their positions. UV/vis. spectral data was employed to calculate the optical energy gap of prepared samples. Antibacterial tests against pathogenic bacteria were performed and correlated to the optical energy gap.

Formation of cluster systems in condensed matters and IR spectra of liquids

Modern approaches to the interpretation of IR spectra of polyatomic liquids are based on cluster models of the structure of matter. First of all it concerns the far infrared region of the spectrum (20-300 cm-1) where rotationally libration motions in the structure of clusters are found. This work is a continuation of research conducted by the authors earlier [G. Melnikov at al. 2015 IOP Conf. Ser Mater. Sci. Eng. 81 p 012032]. The authors have adopted a model in which the appearance of spectral bands is explained by to libration oscillations vibrations of dimers with different configurations in the structure of clusters.

A time-resolved Fourier transformed infrared difference spectroscopy study of the sarcoplasmic reticulum Ca(2+)-ATPase: kinetics of the high-affinity calcium binding at low temperature

We have used time-resolved Fourier transformed infrared difference spectroscopy to characterize the amplitude, frequency, and kinetics of the absorbance changes induced in the infrared (IR) spectrum of sarcoplasmic reticulum Ca(2+)-ATPase by calcium binding at the high-affinity transport sites. 1-(2-Nitro-4,5-dimethoxyphenyl)-N,N,N',N'-tetrakis [(oxycarbonyl)methyl]-1,2-ethanediamine (DM-nitrophen) was used as a caged-calcium compound to trigger the release of calcium in the IR samples. Calcium binding to Ca(2+)-ATPase induces the appearance of spectral bands in difference spectra that are all absent in the presence of the inhibitor thapsigargin. Spectral bands above 1700 cm-1 indicate that glutamic and/or aspartic acid side chains are deprotonated upon calcium binding, whereas other bands may be induced by reactions of asparagine, glutamine, and tyrosine residues. Some of the bands appearing in the 1690-1610 cm-1 region arise from modifications of peptide backbone carbonyl groups. The band at 1653 cm-1 is a candidate for a change in an alpha-helix, whereas other bands could arise from modifications of random, turn, or beta-sheet structures or from main-chain carbonyl groups playing the role of calcium ligands. Only a few residues are involved in secondary structure changes. The kinetic evolution of these bands was recorded at low temperature (-9 degrees C). All bands exhibited a monophasic kinetics of rate constant 0.026 s-1, which is compatible with that measured in previous study at the same temperature in a suspension of sarcoplasmic reticulum vesicles by intrinsic fluorescence of Ca(2+)-ATPase.