Diatomic Interaction Research Articles

Approximate resolutions of the Schrodinger theory applying the WKB approximation for certain diatomic molecular interactions.

The Analyzing of energetic bond spectra of diatomic compounds is crucial to understanding theirqualities because it allows one to evaluate their attributes. Diatoms compounds' spectral properties andbound energies are presented in this study. These energies are found by solving the Schrodinger equationwhile making consideration of the employing of the Kratzer Feus potential. This study focuses on the calculation of bound states for diatomic molecules using the WKBapproximation. The final energy spectrum equation is utilized to compute the bound states of specificdiatomic molecules for varying quantum numbers n and l through the utilization of the Mathematicasoftware. The method produced the desired and anticipated results, as shown by a comparison of theeigenvalue results with earlier studies.

Enhanced conversion of CO2 into C2H4 on single atom Cu-anchored graphitic carbon nitride: Synergistic diatomic active sites interaction

Single atom metal–nitrogen–carbon materials have emerged as remarkably potent catalysts, demonstrating unprecedented potential for the photo-driven reduction of CO2. Herein, a unique Cu@g-C3N5 catalyst obtained by cooperation of single atom Cu and nitrogen-rich g-C3N5 is proposed. The particular CuN diatomic active sites (DAS) in Cu@g-C3N5 contribute to the formation of highly stable CuOCN adsorption, a key configuration for CO2 activation and CC coupling. The synergistic diatomic active sites interaction is found responsible for the efficient photoreduction of CO2 to C2H4 which has been demonstrated in our Gibbs free energy calculation and COHP analysis. The CO2 activation mechanism was studied, the charge density difference and DOS analysis show that the low oxidation state Cu atom significantly affects the electronic structure of g-C3N5 and then enhance the catalytic activity of CO2 hydrogenation.

Potential Energy Surfaces and Arrangement Effects of RbNa2 Complex.

Ab initio calculations of alkaline diatomic molecule interactions with alkaline atoms provide detailed information about their electronic structure, vibrational frequencies, and spectroscopic properties, which are difficult to measure experimentally. This knowledge can aid in designing and interpreting experiments and guide the development of computational models and advanced dynamical calculation. Using the quantum chemistry ab initio methods based on multi-reference configuration interaction with Davidson correction (MCSCF/MRCI + Q), atomic effective core potentials, core-polarization potentials, and the interactions between the sodium atom and the NaRb diatomic molecule are investigated. To describe the potential energy surfaces of the RbNa2 system, we introduce two geometries described in the Z-matrix coordinates (Re, R, θ). Potential energy surfaces of the ground state 12A' and the first excited state 22A' were calculated for different approach directions of the sodium atom to the NaRb molecule and two geometries were considered. The first geometry is where the Na atom approaches the Rb atom of the RbNa dimer, and the second one is when it approaches the Na atom of the RbNa dimer. Global minima of the ground and first excited states and conical intersections between these states are determined for both geometries. The RbNa dimer in interaction with the sodium atom is found to be strongly attractive in its first excited state, which may be important for the experimenters particularly in the field of cold alkali polar dimers. Thereafter, the potential energy curves correlated to the lowest-lying dissociation limits are calculated in the linear form for the two geometrical cases (angle θ at 180°) and the atomic arrangement effect is observed.

Simulation of Internal Defects in TKX-50 Crystals.

1,1'-Dihydroxy-5,5'-bi-tetrazolium dihydroxylamine salt (TKX-50) is a new type of high-energy low-sense explosive with great application value, but TKX-50 made directly from the reaction has problems such as irregular crystal morphology and relatively large length-diameter, and these factors seriously affect the sensitivity of TKX-50 and limit its large-scale application. The internal defects of TKX-50 crystals have a great influence on their weakness, and studying its related properties is of great theoretical significance and application value. To further investigate the microscopic properties of TKX-50 crystals and to explore the connection between microscopic parameters and macroscopic susceptibility, this paper reports the use of molecular dynamics simulations to construct TKX-50 crystal scaling models with three types of defects-vacancy, dislocation and doping-and conducts molecular dynamics simulations. The influence of TKX-50 crystal defects on the initiation bond length, density, bonding diatomic interaction energy, and cohesive energy density of the crystal was obtained. The simulation results show that the models with a higher bond length of the initiator bond and higher percentage activated the initiator's N-N bond and lowered the bond-linked diatomic energy, cohesive energy density, and density corresponding to higher crystal sensitivities. This led to a preliminary connection between TKX-50 microscopic model parameters and macroscopic susceptibility. The results of the study can provide a reference for the design of subsequent experiments, and the research method can be extended to the research work on other energy-containing materials.

Investigation of the role of cell hydrophobicity and EPS production in the aggregation of the marine diatom Cylindrotheca closterium under hypo-saline conditions

Aggregation of diatoms is of global importance to understand settling of particulate organic carbon in aquatic systems. In this study, we investigate the aggregation of the marine diatom Cylindrotheca closterium during the exponential growth phase under hypo-saline conditions. The results of the flocculation/flotation experiments show that the aggregation of the diatom depends on the salinity. In favorable growth conditions for marine diatoms (salinity of 35), the highest aggregation is achieved. To explain these observations, we used a surface approach combining atomic force microscopy (AFM) and electrochemical methods to characterize both the cell surface properties and the structure of the extracellular polymeric substances (EPS) cell produce, and to quantify the amount of surface-active organic matter released. At a salinity of 35, the results showed that diatoms are soft, hydrophobic and release only small amounts of EPS organized into individual short fibrils. In contrast, diatoms adapt to a salinity of 5 by becoming much stiffer and more hydrophilic, producing larger amounts of EPS that structurally form an EPS network. Both adaptation responses of diatoms, the hydrophobic properties of diatoms and the release of EPS, appear to play an important role in diatom aggregation and explain the behavior observed at different salinities. This biophysical study provides important evidence allowing to get a deep insight into diatom interactions at the nanoscale, which may contribute to a better understanding of large-scale aggregation phenomena in aquatic systems.

Exogenous ligand binding kinetics of globin X.

Intrinsically hexa-coordinate vertebrate globins have been shown to carry various cellular functions including neuroprotective and antitumor properties but the precise mechanism of their action remains unclear. Here we focus on the molecular mechanism of diatomic ligand interactions with globin X (GbX) which is a hexa-coordinate globin expressed in lower vertebrate such as fish, amphibians, and reptiles. GbX was proposed to have a variety of enzymatic activities including nitrite reductase, and nitric oxide dioxygenase along with the ability to bind several exogeneous ligands such as O2, CO, and CN-. The wide array of enzymatic functions present in GbX along with its low intracellular concentration in vivo and its hexa-coordination has led to the theory that GbX may serve to scavenge reactive oxygen and nitrogen species. Another interesting feature of GbX is the presence of an internal disulfide bond between residues Cys63 and Cys141 and myristoylation of its N-terminus with an as of yet unknown role in the functional properties of GbX. In this study interactions of exogenous ligands, CO and CN- with GbXWT and GbXH90V and GbXC60A mutants were investigated by combining in vitro and in silica approaches. The results of flash photolysis and stop flow experiments demonstrate multiphasic ligand rebinding to all three constructs with the slowest ligand binding to GbXWT. Time-resolved UV-Vis measurements also revealed multiphasic binding of CN- to GbX. The structures of GbX constructs were determined using homology modeling and subsequent MD simulations and the possible ligand migration pathways were probed using Implicit Ligand Sampling.

Toxic Effect of Metal Doping on Diatoms as Probed by Broadband Terahertz Time-Domain Spectroscopy.

The global marine environment is increasingly affected by human activities causing climate change, eutrophication, and pollution. These factors influence the metabolic mechanisms of phytoplankton species, such as diatoms. Among other pollutant agents, heavy metals can have dramatic effects on diatom viability. Detailed knowledge of the interaction of diatoms with metals is essential from both a fundamental and applicative point of view. To this aim, we assess terahertz time-domain spectroscopy as a tool for sensing the diatoms in aqueous systems which mimic their natural environment. Despite the strong absorption of terahertz radiation in water, we show that diatoms can be sensed by probing the water absorption enhancement in the terahertz range caused by the water–diatom interaction. We reveal that the addition of metal dopants affects this absorption enhancement, thus enabling the monitoring of the toxic effects of metals on diatoms using terahertz spectroscopy. We demonstrate that this technique can detect the detrimental effects of heavy metals earlier than conventional methods such as microscopy, enzymatic assays, and molecular analyses aimed at assessing the overexpression of genes involved in the heavy metal-stress response.

Bi-Mn diatomic interaction on SOD zeolite substrate promotes electrochemical methanol oxidation

The strategy of diatomic synergy is applied to the in-situ synthesis of electrode catalyst material for methanol fuel cells. During the one-pot synthesis in hydrothermal conditions, the doped Bi and Mn atoms are highly dispersed on and immobilized into the SOD zeolite cage structure as nanocrystals with trace amounts to form the novel Bi/Mn/SOD composite catalyst. The as-synthesized Bi and Mn NPs were confined in a rigid SOD nano-cage to maintain the stability and catalytic activity of the monodisperse state. Several key problems to be solved in methanol fuel cell applications are its energy density, catalytic efficiency, stability, and cost. Through the combined action of Mn and Bi, the composite electrode performed high activity in the methanol oxidation reaction (MOR) with a high current density of 45.9 mA cm−2 without precious metal and with high stability in 10 M methanol without any catalyst poisoning.

Spin-Mediated Electron Pairing

IJPSR emphasizes on various innovative, experimental and hypothetical studies related to all aspects of physics. The scope of the journal covers a large range from difficult atoms and diatomic interactions to modelling of atoms and molecules using electromagnetic waves.

Laser Challenge of China

IJPSR emphasizes on various innovative, experimental and hypothetical studies related to all aspects of physics. The scope of the journal covers a large range from difficult atoms and diatomic interactions to modelling of atoms and molecules using electromagnetic waves.

Analytical angular solutions for the atom\u2013diatom interaction potential in a\xa0basis set of products of two spherical harmonics: two approaches

We present general analytical expressions for the matrix elements of the atom–diatom interaction potential, expanded in terms of Legendre polynomials, in a basis set of products of two spherical harmonics, especially significant to the recently developed adiabatic variational theory for cold molecular collision experiments [J. Chem. Phys. 143, 074114 (2015); J. Phys. Chem. A 121, 2194 (2017)]. We used two approaches in our studies. The first involves the evaluation of the integral containing trigonometric functions with arbitrary powers. The second approach is based on the theorem of addition of spherical harmonics.

Accuracy of Morse and Morse-like oscillators for diatomic molecular interaction: A comparative study

This study aims at comprehensively evaluating and comparing the goodness-of-fit of several potential energy curves (PECs), which are Morse, Manning-Rosen, Rosen-Morse and Modified-Rosen-Morse oscillators, to the corresponding experimental Rydberg-Klein-Rees (RKR) or RKR-style data of diatomic molecules. In this work, we also determined vibrational energies of the diatomics based on Bohr-Sommerfeld quantization rule. The goodness-of-fit to RKR data of 34 electronic states of 17 diatomics and the accuracy of the calculated vibrational energies were compared for the four oscillators and reported simultaneously for the first time in this study. These results showed that some oscillators demonstrated better goodness-of-fit than the others. Overall, the (Modified)-Rosen-Morse oscillators generated more accurate vibrational levels for most molecules studied, while Manning-Rosen oscillator was generally better for molecules in their excited electronic states. Although all oscillators performed well for more classical molecules, the Morse oscillator was superior to the other three in describing the ground states of 12C16O and 28Si32S. Particularly, it reproduced all 38 observed experimental ground state vibrational levels of 12C16O with error below 0.79% and even accurately predicted four states unobserved experimentally.

Evidence of Interdomain Ammonium Cross-Feeding From Methylamine- and Glycine Betaine-Degrading Rhodobacteraceae to Diatoms as a Widespread Interaction in the Marine Phycosphere.

Dissolved organic nitrogen (DON) compounds such as methylamines (MAs) and glycine betaine (GBT) occur at detectable concentrations in marine habitats and are also produced and released by microalgae. For many marine bacteria, these DON compounds can serve as carbon, energy, and nitrogen sources, but microalgae usually cannot metabolize them. Interestingly though, it was previously shown that Donghicola sp. strain KarMa—a member of the marine Rhodobacteraceae—can cross-feed ammonium such that the ammonium it produces upon degrading monomethylamine (MMA) then serves as nitrogen source for the diatom Phaeodactylum tricornutum; thus, these organisms form a mutual metabolic interaction under photoautotrophic conditions. In the present study, we investigated whether this interaction plays a broader role in bacteria–diatom interactions in general. Results showed that cross-feeding between strain KarMa and P. tricornutum was also possible with di- and trimethylamine as well as with GBT. Further, cross-feeding of strain KarMa was also observed in cocultures with the diatoms Amphora coffeaeformis and Thalassiosira pseudonana with MMA as the sole nitrogen source. Regarding cross-feeding involving other Rhodobacteraceae strains, the in silico analysis of MA and GBT degradation pathways indicated that algae-associated Rhodobacteraceae-type strains likely interact with P. tricornutum in a similar manner as the strain KarMa does. For these types of strains (such as Celeribacter halophilus, Roseobacter denitrificans, Roseovarius indicus, Ruegeria pomeroyi, and Sulfitobacter noctilucicola), ammonium cross-feeding after methylamine degradation showed species-specific patterns, whereas bacterial GBT degradation always led to diatom growth. Overall, the degradation of DON compounds by the Rhodobacteraceae family and the subsequent cross-feeding of ammonium may represent a widespread, organism-specific, and regulated metabolic interaction for establishing and stabilizing associations with photoautotrophic diatoms in the oceans.

Diatoms Are Selective Segregators in Global Ocean Planktonic Communities.

Diatoms are a major component of phytoplankton, believed to be responsible for around 20% of the annual primary production on Earth. As abundant and ubiquitous organisms, they are known to establish biotic interactions with many other members of plankton. Through analyses of cooccurrence networks derived from the Tara Oceans expedition that take into account both biotic and abiotic factors in shaping the spatial distributions of species, we show that only 13% of diatom pairwise associations are driven by environmental conditions; the vast majority are independent of abiotic factors. In contrast to most other plankton groups, on a global scale, diatoms display a much higher proportion of negative correlations with other organisms, particularly toward potential predators and parasites, suggesting that their biogeography is constrained by top-down pressure. Genus-level analyses indicate that abundant diatoms are not necessarily the most connected and that species-specific abundance distribution patterns lead to negative associations with other organisms. In order to move forward in the biological interpretation of cooccurrence networks, an open-access extensive literature survey of diatom biotic interactions was compiled, of which 18.5% were recovered in the computed network. This result reveals the extent of what likely remains to be discovered in the field of planktonic biotic interactions, even for one of the best-known organismal groups.IMPORTANCE Diatoms are key phytoplankton in the modern ocean that are involved in numerous biotic interactions, ranging from symbiosis to predation and viral infection, which have considerable effects on global biogeochemical cycles. However, despite recent large-scale studies of plankton, we are still lacking a comprehensive picture of the diversity of diatom biotic interactions in the marine microbial community. Through the ecological interpretation of both inferred microbial association networks and available knowledge on diatom interactions compiled in an open-access database, we propose an ecosystems approach for exploring diatom interactions in the ocean.

Confinement effects on the diatomic interaction potential

Confinement effects on the interaction potential between two ground-state hydrogen atoms located inside a hard spheroidal box and with varying internuclear separations R are presented. The results of this work point to a redefinition of the calculation of binary interactions when two atomic systems are initially submitted to spatial limitation by physical or geometric boundaries. This unique characteristic of spatial confinement points to a necessary revision of the calculation of vibrational and rotational properties of diatomic molecules inside nanometric cages.

The Impact of Magnetic Dipole Radiation and Decay on the Variation of Period and Inclination Angle of Pulsars

IJPSR emphasizes on various innovative, experimental and hypothetical studies related to all aspects of physics. The scope of the journal covers a large range from difficult atoms and diatomic interactions to modelling of atoms and molecules using electromagnetic waves.

A bulk adjusted linear combination of atomic orbitals (BA-LCAO) approach for nanoparticles.

We describe a bulk adjusted linear combination of atomic orbitals (BA-LCAO) approach for nanoparticles. In this method, we apply a many-body scaling function (in similar manner as in the environment-modified total energy based tight-binding method) to the DFT-derived diatomic AO interaction potentials (like in the conventional orbital-based density-functional tight binding approach) strictly according to atomic valences acquired naturally in a bulk structure. This modification, (a) facilitates all atom orbital-based electronic structure calculations of charge carrier dynamics in nanoscale structures with a molecular acceptor, and (b) allows to closely match high-level density functional calculation data (previously adjusted to the available experimental findings) for bulk structures. To advance practical application of the BA-LCAO approach we parameterize the Hamiltonian of wurtzite CdSe by fitting its band structure to a high-level DFT reference, corrected for experimentally measured band edges. Here, unlike in conventional DFTB approach, we: (1) use hydrogen-like AOs for the basis as exact atomic eigenfunctions, while orbital energies of which are taken from experimentally measured ionization potentials, and (2) parameterize the many-body scaling functions rather than the atomic wavefunctions. Development of this approach and parameters is guided by our goals to devise a method capable of simultaneously treating the problems of (i) interfacial electron/hole transfer between finite, variable size nanoparticles and electron scavenging molecules, and (ii) high-energy electronic transitions (Auger transitions) that mediate multi-exciton decay in quantum dots. Electronic structure results are described for CdSe quantum dots of various sizes. © 2018 Wiley Periodicals, Inc.

Calculations with experimental validations of cross-sections and transport coefficients of Xe+ colliding with Xe

Mobility and diffusion coefficients of ions in xenon gas and related momentum transfer cross-sections (MTCSs) for /Xe collisions are calculated using two different sets of diatomic interaction potentials and various theoretical approaches. MTCSs are obtained using four different methods: quantum method where both electrons and atomic nuclei are treated quantum mechanically, semi-classical method taking advantage of the Jeffreys–Wentzel–Kramers–Brillouin approximation applied to atomic nuclei, hybrid method where electrons are treated quantum mechanically while classical treatment is used for atomic nuclei, and a semi-empirical inverse method within which the cross-sections are extracted from available measurements on the mobility in xenon gas. Mobility and diffusion coefficients are calculated at ambient pressure and temperature for a broad range of the reduced electric field ( Td) using a Monte Carlo approach. A thorough comparison with available experimental data is provided.

Quantum and semi-classical collision cross-sections and transport data for a Kr+/Kr system

Krypton ion transport properties in krypton carrier gas have been calculated using various methods and two state-of-the-art sets of diatomic interaction potentials and compared to available experimental data. First, momentum transfer effective cross-sections have been calculated for Kr+/Kr collisions for the ion in either of two fine-structure states ( and ). A full quantum approach, semi-classical approximation, and a hybrid method (classical treatment of nuclei and quantum description of electrons) have been used. Then, an optimized Monte Carlo code has been employed to calculate the basic transport parameters (mobility and diffusion coefficients) of the Kr+ ion in the carrier krypton gas. A thorough comparison of the calculated data with available experiments allowed the assessment of the reliability of the interaction models and methodologies to be used in further calculations. In addition, theoretical predictions are provided for these coefficients where they are not available from measurements.

On the Unusual Synclinal Conformations of Hexafluorobutadiene and Structurally Similar Molecules.

An explanation is presented for the unusual conformations of some molecules that contain the C═C-C═C core, namely, butadienes, biphenyls, and styrenes. Small substituents often induce a synclinal conformation, which brings the substituents into close proximity, and sometimes, there is no anticlinal minimum at all. This would not be predicted from steric repulsion arguments nor would it be expected that atoms that are nonbonded in a Lewis structure would approach closer than the sum of their van der Waals radii. Atomic energies calculated according to the quantum theory of atoms in molecules (QTAIM) do not show a consistent pattern for these structurally similar molecules, nor are intersubstituent bond paths consistently found, nor favorable diatomic interaction energies calculated using the interacting quantum atoms (IQA) scheme. Instead, the synclinal conformations are found to be driven by the attraction energy of the electron distribution of the carbon atoms and the nuclei of the molecule.