Charged Ions Research Articles

Complexation of lanthanide ions with citric acid in aqueous solutions

The stability constants of triply charged lanthanide ions complexes with citric acid of 1:2 stoichiometry weremeasured by potentiometric titration in a wide pH range, and the relationship between the constants and the lanthanide type was analyzed. A mathematical model for the equilibrium in studied solutions was proposed.

A Study of the Atomic Processes of Highly Charged Ions Embedded in Dense Plasma

The study of atomic spectroscopy and collision processes in a dense plasma environment has gained a considerable interest in the past few years due to its several applications in various branches of physics. The multiconfiguration Dirac-Fock (MCDF) method and relativistic configuration interaction (RCI) technique incorporating the uniform electron gas model (UEGM) and analytical plasma screening (APS) potentials have been employed for characterizing the interactions among the charged particles in plasma. The bound and continuum state wavefunctions are determined using the aforementioned potentials within a relativistic Dirac-Coulomb atomic structure framework. The present approach is applied for the calculation of electronic structures, radiative properties, electron impact excitation cross sections and photoionization cross sections of many electron systems confined in a plasma environment. The present study not only extends our knowledge of the plasma-screening effect but also opens the door for the modelling and diagnostics of astrophysical and laboratory plasmas.

Understanding Students’ Misconceptions about Chemical Formula Writing and Naming Ionic Compounds

Difficulties in the competency of chemical formula writing and naming ionic compounds are common to General Chemistry 1 learners. Hence, this study is formulated to understand 34 General Chemistry 1 learners' misconceptions about chemical formula writing and naming ionic compounds. This descriptive case study research used a two-tier test and interview questionnaire as the main data-gathering instruments. From the conducted study, analysis shows that in terms of chemical formula writing, the learners misrepresent ionic compounds as charged species, show a lack of understanding of valency and the use of the cross-charge method, and mispresent radicals. In naming ionic compounds, the learners generally misname some of the elements found in binary ionic compounds and misname metal ions with more than 1 charge and polyatomic ions. These misconceptions were validated by the difficulties experienced by the learners in answering the two-tier test, as mentioned in their interviews. Despite the misconceptions and difficulties of the learners in chemical formula writing and naming ionic compounds, they mentioned several ways of addressing them.

Synthesis, Characterization and Potential Antimicrobial Activity of Selenium Nanoparticles Stabilized with Cetyltrimethylammonium Chloride.

Selenium nanoparticles (Se NPs) have a number of unique properties that determine the use of the resulting nanomaterials in various fields. The focus of this paper is the stabilization of Se NPs with cetyltrimethylammonium chloride (CTAC). Se NPs were obtained by chemical reduction in an aqueous medium. The influence of the concentration of precursors and synthesis conditions on the size of Se NPs and the process of micelle formation was established. Transmission electron microscopy was used to study the morphology of Se NPs. The influence of the pH of the medium and the concentration of ions in the sol on the stability of Se micelles was studied. According to the results of this study, the concentration of positively charged ions has a greater effect on the particle size in the positive Se NPs sol than in the negative Se NPs sol. The potential antibacterial and fungicidal properties of the samples were studied on Escherichia coli, Micrococcus luteus and Mucor. Concentrations of Se NPs stabilized with CTAC with potential bactericidal and fungicidal effects were discovered. Considering the revealed potential antimicrobial activity, the synthesized Se NPs-CTAC molecular complex can be further studied and applied in the development of veterinary drugs, pharmaceuticals, and cosmetics.

Improvement of Ionization Efficiency and Application of Structural Analysis for MALDI-TOFMS by Derivatization of Polyacrylic Acid.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is a suitable method for polymer analysis. MALDI is a soft ionization technique that can generate mainly singly charged ions. Therefore, the polymer's molecular weight distribution is easy to analyze, facilitating the calculation of the number average molecular weight and weight average molecular weight and polydispersity. However, there are polymers that are difficult to detect by MALDI-TOFMS. For example, polyacrylic acid includes carboxylic acid in the main chain, which is difficult to measure due to its low ionization efficiency. As a solution, the ionization efficiency was improved by methylation. In this technical report, we introduce a method to utilize derivatization to determine the degree of polymerization by accurate mass spectrometry (MS). Furthermore, the structures of both ends of the polymers were estimated by tandem time-of-flight MS.

Effects of Amino Acid Additives on Protein Stability during Electrothermal Supercharging in ESI-MS.

The surprising formation of highly charged protein ions from aqueous ammonium bicarbonate solution is a fascinating phenomenon referred to as electrothermal supercharging (ETS). Although the precise mechanism involved is not clearly understood, previous studies predominantly suggest that ETS is due to native protein destabilization in the presence of bicarbonate anion inside the electrospray ionization droplets under high temperatures and spray voltages. To evaluate existing hypotheses surrounding the underlying mechanism of ETS, the effects of several additives on protein charging under ETS conditions were investigated. The changes in the protein charge state distributions were compared by measuring the ratios between the intensities of highest intensity charge states of native and unfolded protein envelopes and shifts in the lowest and highest observed charge states. This study demonstrated that source temperature plays a more important role in ETS compared to spray voltage, especially when using a nebulized microelectrospray ionization source. Moreover, the effect of amino acids on ETS were generally in good agreement with the extensive literature available on the stabilization or destabilization of proteins by these additives in bulk solution. Among the natural amino acids, protein supercharging was significantly reduced by proline and glycine; however, imidazole provided the highest degree of noncovalent complex stabilization against ETS, outperforming the amino acids. Overall, our study shows that the simple addition of stabilizing reagents such as proline and imidazole can reduce the extent of apparent protein unfolding and supercharging in ammonium bicarbonate solution and provide evidence against the roles of charge depletion and thermal unfolding during ETS.

Ionic liquid based electroless silver plating bath for Printable circuit boards (PCBs) finishing

Immersion silver-plating technique is typically used for uniform coating on printed circuit boards (PCB) for finishing. Herein, we report an unconventional protocol for preparation of non-toxic immersion silver-plating solution/bath. The solution was prepared through electrolysis using ionic liquid (1, 3-disulfonic acid imidazolium hydrogen sulfate [Dsim] [HSO4]) as electrolyte, metallic silver (Ag) as anode and copper as cathode. As a result of electrolysis, IL-capped aqueous charged silver ion (Ag+) solution [colloidal Ag-IL adduct solution] is obtained. Presence of Ag+ in solution was verified by cyclic voltammetry (CV) experiments. Chemical reduction of Ag+ with Hydrazine Hydrate (NH2-NH2·H2O) yielded AgNPs. The AgNPs analyzed through dynamic light scattering (DLS) exhibiting 269.99 ± 14.2 nm size with Polydispersity Index (PDI) 0.126. The metallic copper strip immersed into the solution and a shiny silver plated surface obtained within 1–5 min at room temperature. Film thickness can be controlled by varying time of immersion. The corrosion rate was found to be 0.0012 mm/a by Tafel fitting. The solution is stable for the months without losing efficiency whereas the recovered IL used five times without significant loss in efficiency.

Collinear laser spectroscopy of highly charged ions produced with an electron-beam ion source

Collinear laser spectroscopy of highly charged ions produced with an electron-beam ion source

Theoretical investigation on the spectra of M1 transition of W53+ ion

The properties and spectrum of the highly charged tungsten ions draw more and more attention, due to its potential application in the next generation fusion reactor. The transition wavelength and rate of the magnetic-dipole transition between the levels of the ground configuration of W53+ ion in the range of 10−20 nm were calculated by Dirac–Fock–Slater (DFS) method with a local central potential and Multi-Configuration Dirac-Hartree-Fock (MCDHF) method, respectively. The results are consistent with the previous EBIT experimental data and other theoretical data. A collisional-radiative model was constructed, and the spectrum of magnetic-dipole transition of W53+ ion observed on EBIT (Y. Ralchenko et al., Phys. Rev. A. 83, 032517, 2011) was reproduced theoretically. Another two new transitions near the wavelength of 16.683 nm and 18.018 nm are also assigned to the M1 transition of W53+ ion.

Dust acoustic inertial Alfvénic nonlinear structures in an electron depleted dusty plasma

In this investigation, the propagation properties of dust inertial Alfvén wave (DIAW) solitons, rogons, and breather structures have been studied in a magnetised electron-depleted two fluids plasma consisting of negatively charged dust and positively charged ions. The Korteweg–de Vries (KdV) equation has been derived by using the reductive perturbation method (RPM) to study the properties of solitons. Further, the nonlinear Schrödinger equation (NLSE) has also been derived by employing a suitable transformation in the KdV equation. The evolution of various kinds of nonlinear structures such as rogons, Akhmediev breathers (AB), and Kuznetsov–Ma breathers (KM) has been elucidated from the different rational solutions of the nonlinear Schrödinger equation. The impact of various physical parameters, such as the dust plasma beta and the angle of propagation of different species, on the salient properties of DIAW solitons, rogons, and breather structures has been studied numerically.

Computational and crystallographic study of hydrogen bonds in the second coordination sphere of chelated amino acids with a free water molecule: Influence of complex charge and metal ion

Hydrogen bonds of glycine complexes were calculated using quantum chemistry calculations at M06L-GD3/def2-TZVPP level and by analyzing the crystal structures from the Cambridge Structural Database (CSD). One hydrogen bond where amino acid plays the role of the H-donor (NH/O), and two where it plays the role of the H-acceptor (O1/HO, O1 is a coordinated oxygen atom, and, O2/HO, O2 is a non-coordinated oxygen atom) were investigated. The calculations were done on octahedral nickel(II), square pyramidal copper(II), square planar copper(II), palladium(II), and platinum(II) glycine complexes with different charges adjusted using water(s) and/or chlorine ion(s) as the remaining ligands. For NH/O hydrogen bond, interaction energies of neutral complexes are the weakest, from −5.2 to −7.2 kcal/mol for neutral, stronger for singly positive, from −8.3 to −12.1 kcal/mol, and the strongest for doubly positive complex, −16.9 kcal/mol. For O1/HO and O2/HO interactions, neutral complexes have weaker interaction energies (from −2.2 to −5.1 kcal/mol for O1/HO, and from −3.7 to −5.0 kcal/mol for O2/HO), than for singly negative complexes (from −6.9 to −8.2 kcal/mol for O1/HO, and from −8.0 to −9.0 kcal/mol for O2/HO). Additionally to the complex charge, metal oxidation number, coordination number, and metal atomic number also influence the hydrogen bond strength, however, the influence is smaller.

Synthesis and characterization of microcrystals cellulose from citronella waste (Cymbopogon nardus L.) as a filler in graphene oxide

One of the energy storage materials that is interesting to research is graphene-based. Electrodes from multiple layers of graphene oxide can produce dense porous materials capable of trapping charged ions of various sizes. Graphene-based materials generally need to be composited to prevent layer buildup, resulting in less than optimal energy storage characteristics. Microcrystal cellulose should be added to reduce the formation of the graphene layer and increase the pore size. Microcrystal cellulose are produced by decomposing and separating the parts of natural cellulose crystals. One type of grass in Bangka Belitung is the citronella (Cymbopogon nardus). The cellulose yield from citronella waste is 22%. Based on FTIR spectroscopy, there are typical functional groups of cellulose such as C=O, C-H, C-O, and C-O-C groups. The size of the cellulose microcrystals obtained is 49.47 µm.

Analysis the Water Quality Parameters of Ground sample with Special Reference to Fluoride in different Locations of Malpura (Tonk District, Rajasthan, India)

Water is essential natural resources for sustaining life and environment that we have always thought to be available in abundance and free gift of nature. The present study was carried out to analysis of various water quality parameters with special reference to Fluoride to examine the major suitability of water for, irrigation, domestic and drinking use. Fluoride concentration in the study area varied from 0.5mg/L to 6.90mg/L with an average of 3.17mg/L. The presence of excessive quantity of fluoride in drinking water is accompanied by a characteristic sequence of changes in teeth and bone. Fluoride is attracted by positively charged calcium ions in teeth and bones and can result in pathological changes in teeth and bones, such as mottling of teeth or dental fluorosis followed by skeletal fluorosis. Groundwater is a major source of human intake of fluoride.

The characteristics and flocculation mechanisms of SMP and B-EPS from a bioflocculant-producing bacterium Pseudomonas sp. XD-3 and the application for sludge dewatering

In this study, a novel bacterium Pseudomonas sp. XD-3 with bioflocculant-producing capability was identified and characterized. Strain XD-3 produced two kinds of flocculating active substances, soluble microbial products (SMP) and bound extracellular polymers substances (B-EPS). The flocculation efficiency of SMP was about 79.3% and that of B-EPS was 79.9%. Charge neutralization, ion bridging and hydrogen bonding played important roles in the flocculation of SMP, while ion bridging and hydrophobic force dominated the flocculation in B-EPS. Spectral analysis revealed that –OH and –COO- in SMP and B-EPS provided abundant binding sites for ion bridging. The presence of CNH3+ in SMP participated in charge neutralization. The hydrophobic groups of C-(C/H) and OC contributed to the hydrophobic force of B-EPS. In addition, both SMP and B-EPS contained proteins secondary structures that were beneficial for bioflocculation, such as α-helix, three-turn helices, β-sheet and aggregated strands. B-EPS exhibited satisfied sludge dewatering effect, with a water content reduction from 93.66% to 83.9% and a specific resistance to filtration (SRF) reduction from 13.48 × 1012 m/kg to 7.74 × 1012 m/kg. The composite flocculant of B-EPS and Al2(SO4)3 further reduced the SRF to 1.54 × 1012 m/kg at pH 4, CaCl2 dosage 23.3 g/kg, B-EPS 0.93 g/kg and Al2(SO4)3 150 g/kg.

Ionization of CH[formula omitted] under fast He-like Si-ion impact

We have studied the absolute double differential cross section (DDCS) of electrons ejected from the methane molecule (CH4) under the impact of highly charged fast projectile ions. The energy and angular distributions of electrons have been measured in interactions with 70 MeV Si12+ ions. These DDCS data together with the derived single differential cross sections and the total cross section (TCS) have been compared with predictions of the continuum distorted wave-eikonal initial state model using different approaches for the molecular orbitals. It has been found that the theories overestimate the measured DDCS values at low ejection energies, which may indicate shortcomings of the model in the case of strong perturbation. At the same time, applying the model to a previous measurement using fast C ions having a lower perturbation strength, excellent agreements have been obtained with the experimental data. Considering the scaling properties, the available TCS data have been plotted with a scaled parameter, namely the perturbation strength, q/v (where q= charge state, v=velocity of the projectile). The KLL Auger e-emission as well as the KLL hyper-satellite peaks are analyzed for different emission angles. The double K-vacancy production shows a considerable enhancement i.e. 37% of the single production cross section which is consistent with some of the recent experiments on K-ionization using x-ray techniques.

Redox-active 9,10-phenanthrenequinone non-covalently modify reduced graphene oxide for high-performance asymmetric supercapacitor and zinc-ion hybrid capacitors

Redox-active organic molecules show great potential in novel renewable energy storage devices by modifying carbon-based materials in covalent or non-covalent forms due to their light-weight, rich structural diversity, good designability and abundance. Herein, we synthesized redox-active 9,10-phenanthrenequinone (PQ) molecules non-covalently modified reduced graphene oxide (RGO) nanocomposites by an improved simple one-step solvothermal method and explored their application as advanced electrode in aqueous energy storage devices. Benefiting from the rich redox-active sites brought by the anchored PQ molecules and the formation of the hierarchical porous network nanostructures with the RGO substrates that facilitates the charge transport and ion diffusion kinetics, the synthesized RGO/PQs nanocomposites exhibit significantly enhanced electrochemical energy storage performance. The optimal RGO/PQ-1.5 electrode has a high specific capacitance of 383.3 F g−1 at 0.5 A g−1 and good rate capability. And the asymmetric supercapacitor (ASC) assembled with the N-RGO negative electrode exhibits significantly better energy density than pure carbon electrode ASCs. More surprisingly, the assembled RGO/PQ-1.5//Zn zinc-ion hybrid capacitor exhibits an attractive specific capacity of 139.4 mAh g−1, a high energy density of 134.6 Wh kg−1, and an ultra-long cycling stability with 95.3 % capacity retention after 14,000 cycles, demonstrating excellent zinc-ion energy storage performance.

A retarding field thermal probe for combined plasma diagnostics

The wide variety and ever-growing applications of plasma processes in research and industry require an equally growing diversity and accessibility of suitable plasma diagnostics. The plasma parameters and the tailoring thereof strongly influence the outcome of thin film deposition, plasma etching, or surface treatments, to name only a few. To further enhance the determination of different fluxes of species, their energies, and behaviour influencing a surface process, a custom-built combination of two commonly used diagnostics was developed. With a retarding field energy analyzer, one can obtain the ion energy distribution in a plasma by measuring the current at the collector depending on the applied voltage at the scan grid. A passive thermal probe determines the energy flux density coming from a process plasma by measuring the temperature change of a dummy substrate. In this study, we present a retarding field energy analyzer where a passive thermal probe substitutes the collector. By doing so, we can determine the energy distribution of the charged ions, their energy flux density at a certain potential, and the power deposited onto a substrate. Another advantage is that the thermal probe can even measure the power deposited by incoming (fast) neutrals and of the background gas when the grids keep away the ions. Hence, combining these two powerful diagnostics yields information neither can deliver on their own. The probe has been tested in three different plasma environments: ion beam source, magnetron sputtering and radio frequency discharge plasma.

Numerical model of a gaseous inductive discharge in oxygen, taking into account the complete scheme of the vibrational kinetics of O2 molecules

In this work, the two-dimensional model of inductively coupled plasma discharge in oxygen was developed. The model includes hydrodynamic equations in drift-diffusion approximation for describing the kinetics of charged (electrons and ions) and neutral plasma particles, Maxwell’s equations for electromagnetic fields, and equations for the temperature and neutral gas flow as well as a detailed scheme of plasma-chemical reactions. The model was tested against theoretical and experimental data in a simple cylindrical chamber. The electron density and temperature distributions were obtained over a wide range of powers deposited in the plasma (100–500 W) and compared with literature data. Also, the complete scheme of the vibrational kinetics of O2 molecules was included in the model. The vibrational distribution function was calculated in low-pressure inductive discharge as well as spatial distributions of plasma parameters (density and temperature of electrons, excited components, neutral gas temperature, etc.) and flows of charged and active neutral particles at the reactor walls.

The Role of Collision Ionization of K-Shell Ions in Nonequilibrium Plasmas Produced by the Action of Super Strong, Ultrashort PW-Class Laser Pulses on Micron-Scale Argon Clusters with Intensity up to 5 × 1021 W/cm2

The generation of highly charged ions in laser plasmas is usually associated with collisional ionization processes that occur in electron–ion collisions. An alternative ionization channel caused by tunnel ionization in an optical field is also capable of effectively producing highly charged ions with ionization potentials of several kiloelectronvolts when the laser intensity q > 1020 W/cm2. It is challenging to clearly distinguish the impacts of the optical field and collisional ionizations on the evolution of the charge state of a nonequilibrium plasma produced by the interaction of high-intensity, ultrashort PW-class laser pulses with dense matter. In the present work, it is shown that the answer to this question can be obtained in some cases by observing the X-ray spectral lines caused by the transition of an electron into the K-shell of highly charged ions. The time-dependent calculations of plasma kinetics show that this is possible, for example, if sufficiently small clusters targets with low-density background gas are irradiated. In the case of Ar plasma, the limit of the cluster radius was estimated to be R0 = 0.1 μm. The calculation results for argon ions were compared with the results of the experiment at the J-KAREN-P laser facility at QST-KPSI.

Correction to: Calculated Stark widths of the triply charged argon ion Ar iv

Correction to: Calculated Stark widths of the triply charged argon ion Ar <scp>iv</scp>