Doubly-charged Ions Research Articles

Overall Concept Design of 2.45 GHz ECR Ion Source with Tunable Magnetic Field

The design of the ECR ion source was made for an operating frequency of 2.45 GHz. The ion source is considered to be used for producing protons and double charged helium ions. The source construction as well as the separate components design are presented in the study. The operating modes include both ECR and microwave operating regimes. The extraction system with the beamforming was developed. The beam adjustment is implemented by the longitudinal shifting of the electrodes against the plasma electrode position. The performance of the 2.45 GHz waveguide line to provide the stable power injection into the plasma chamber is considered. The numerical simulation of the waveguide line components was made and optimised.

Double layer acceleration of ions with differently charged states in a laser induced plasma

The electric field driven acceleration of plasma ions is an intrinsic effect in laser-induced plasma plumes and is responsible for the generation of high-energy ions. At high laser fluences (≥ 2 J/cm2), multiply charged ions are formed and affect the plume expansion dynamics. In this paper, we used kinetic energy-resolved mass spectrometry to investigate the relative abundance and kinetic energy distributions of singly- and doubly-charged ions produced by KrF-laser ablation of nine different oxide targets. The doubly charged metal ions with a lower mass-to-charge (m/z) ratio show narrow energy distributions at high average kinetic energies coinciding with the cutoff energies for the singly-charged ion distributions. The observation suggests that the recombination of higher charged ions plays a prominent role in the formation of the high-energy tail for singly-charged ions. The results are discussed in terms of component volatility and a dynamic double layer, where ions with different m/z values experience different accelerations.

STUDY OF VACUUM HIGH-GRADIENT BREAKDOWNS FROM THE ION-MODIFIED SURFACE OF COPPER ELECTRODES

The influence on the resistance to high-voltage breakdown of samples irradiated with double-charged copper ions Cu2+ with an energy of 300 keV and different irradiation doses was studied. It is experimentally shown that when irradiating a copper electrode with Cu2+ ions, the values of breakdown characteristics improve by 17…28% with increasing irradiation dose. A theoretical study of the effect of material defects such as pores on the emission current was carried out. It is shown that the field emission current from the metal surface near nano-objects has a vibrational resonance feature. The resonance condition is determined by the depth of the nanoscale void from the metal surface. If the resonance conditions are not met or if the size of the defects increases, the emission current decreases rapidly.

SORPTION OF IONS OF SOME METAL ON CLINOPTILOLITE IN THE PRESENCE OF GALLIC ACID

The Gibbs energy changes for the reaction between the copper, cadmium, and lead ions complexes with gallic acid and clinoptilolite containing single-charged (Na, K) and double-charged (Ca, Mg) exchange ions were calculated. The software PRIRODA with the PBE/3ζ theoretical method has been used for these calculations:
 (GalAn)2X×2H2O + Clin-Me + 2H3O+ → X(H2O)n-Clin + 2GalAn– + (6-n)H2O + 2Me+(Me2+).
 The thermodynamic possibility of spontaneous ion exchange between complexes of heavy metal ions (Cu2+, Cd2+, Pb2+) with gallic acid and exchange ions of clinoptilolite was shown. This indicates the possibility of removal of these ions from the soil, with their coordination by polyphenols. The possibility of a significant decrease in the content of Cu2+, Cd2+, and Pb2+ ions was investigated both in the absence of gallic acid and in its presence in solution (initial concentration of metal ions of 2 mmol/l, the ratio of Me2+: gallic acid is 1:0, 1:1, and 1:2). It has been found that the sodium form of clinoptilolite influences the growth of sorption properties of clinoptilolite, allowing to exclude 22% more copper ions, compared to the natural clinoptilolite of Sokyrnytsya deposit. Two mechanisms for reducing the concentration of heavy metals in soil have been proposed.
 Keywords: clinoptilolite; sorption; heavy metal; quantum-chemical calculations; gallic acid.

P284 POTENTIAL PROARRHYTHMIC SIDE EFFECT OF HIGH DOSE AND PROLONGED SODIUM NITROPRUSSIDE INFUSION THROUGH CALCIUM ION REDUCTION

Abstract Patient presentation. A fifty y/o male patient with a history of congenital aortic stenosis surgically corrected previously and with chronic heart failure due to severe left ventricular dysfunction presented to our emergency department complaining dyspnea. Due to acute decompensated heart failure with ongoing cardiogenic shock, he was admitted to our intensive cardiology unit. Initial work up. The blood exams showed a normal renal and liver function, normal total and free calcium, 9.4 mg/dL and 1.16 mmol/L respectively, lactates were mildly increased. The chest x–ray showed pulmonary congestion. At the echocardiography we found severe biventricular dysfunction, moderate mitral regurgitation, severe pulmonary hypertension. Since the patient was unstable, adrenaline, high–dose sodium nitroprusside (SNP), and intra–aortic balloon pump were started. The right heart catheterization revealed combined pulmonary hypertension reversible with SNP and, therefore, the patient was inserted in the heart transplant list. Diagnosis and Management. One of the side effects of SNP is the thiocyanate toxicity. A high dose of SNP was necessary for this patient (2.2 mcg/kg/min). Thus, thiocyanate levels increased up to 10 mg/100 mL (NV<3). Importantly, the patient was asymptomatic despite these levels. However, the free calcium ion progressively decreased up to 0.94 mmol/L, despite normal total calcium and calcium supplementation iv and orally. Since arrhythmic burden markedly increased, we started lidocaine which was not effective. Follow–up. Since we suspected a possible causative role of thiocyanate, which might bond the double positive charged free calcium ion with its two negatively charged sulfur atoms, explaining the normal total calcium level and the low calcium ion, we carefully reduced SNP dose within days. This allowed us to reduce thiocyanate to 6 mg/100 mL, without compromising patient hemodynamics. Concomitantly, the free calcium ion tended to normalize, lowering the arrhythmic burden. Conclusions We describe for the first time a proarrhythmic side effect of prolonged SNP infusion, likely related to thiocyanate accumulation and free calcium ion binding, which, despite aggressive calcium supplementation, was normalized only after SNP down titration.

Confined water transport and desalination mechanism through lamellar Boron-Nitride Channels: A molecular dynamics simulation study

The lamellar channels created by hexagonal boron nitride sheets (hBNSs) offer great promise as membranes for RO desalination plants. However, boron nitride nanochannels (BNNCs) have not yet been extensively explored for their desalination mechanisms. Therefore, to address this gap of knowledge, in this study, molecular dynamics simulations (MDs) are used to investigate the performance of BNNCs in water desalination applications. For this purpose, the effect of various parameters, including channel height in the range of 6.14 Å to 12.38 Å, applied pressure, ion concentration, and membrane flexibility are evaluated. Results show that for channel height ranging 6.14 Å to 8.77 Å, the rejection percentage of double-charged ions is more than single-charged ions. In contrast, this trend is reversed for larger channel heights. Another important point is that 7.675 Å can be selected as an optimum channel height for a design of BNNC membranes. Moreover, the water permeation and ion rejection of flexible membrane decrease and increase, respectively, compared to the rigid membrane. In addition, the Boron Nitride-Nanoflake nanochannel membranes (BNFNC) are investigated as a realistic model of nanosheet-based membranes. Finally, the results of the present study propose that BNNCs can be an appropriate membrane for RO desalination plants.

Investigation of the spatial distribution characteristics of multiple species in a vacuum arc

The spatial distribution of multiple species in a vacuum arc is an essential microscopic feature. Ionization, recombination, and species diffusion are the main factors affecting the distribution of arc particles. The purpose of this paper is to investigate the spatial distribution characteristics of multiple species in a vacuum arc using a high-speed camera and interference filters. CuCr50 and pure copper plate electrodes were used to conduct arc-burning experiments in a demountable vacuum chamber. The distribution of different species was obtained by arranging interference filters outside the quartz glass window. The experimental results show that most neutral atoms originated from the evaporation of the electrode material and were distributed on the electrode surface. Strong ionization of ions and atoms near the cathode caused the number of single-charged ions to increase, and their ion density gradually decreased along the axial direction with increasing distance from the cathode. Double-charged ions were mainly distributed near the anode where the electron temperature was higher, and their density increased along the axial direction with increasing distance to the cathode. The above conclusions provide a basis for further research on the characteristics of microscopic particles in vacuum arcs.

Drone Delivery of Dehydro-Sulfurization Utilizing Doubly-Charged Negative Ions of Nanoscale Catalysts Inspired by the Biomimicry of Bee Species’ Bio-Catalysis of Pollen Conversion to Organic Honey

The sulfur dioxide (SO2) compound is a primary environmental pollutant worldwide, whereas elemental sulfur (S) is a global commodity possessing a variety of industrial as well as commercial functions. The chemical relationship between poisonous SO2 and commercially viable elemental S has motivated this investigation using the Density Functional Theory calculation of the relative transition state barriers for the two-step dehydro-sulfurization oxidation–reduction reaction. Additionally, doubly-charged nanoscale platelet molybdenum disulfide (MoS2), armchair (6,6) carbon nanotube, 28-atom graphene nanoflake (GR-28), and fullerene C-60 are utilized as catalysts. The optimal heterogeneous and homogeneous catalysis pathways of the two-step oxidation–reduction from SO2 to elemental S are further inspired by the biomimicry of the honeybee species’ multi-step bio-catalysis of pollen conversion to organic honey. Potential applications include environmental depollution, the mining of elemental sulfur, and the functionalization of novel technologies such as the recently patented aerial and amphibious LynchpinTM drones.

Use of group IIB metal ions as charge carriers for collision-induced dissociation of glycopeptide and glycan.

Dissociation of biomolecules by tandem mass spectrometry (MS/MS) generates a variety of fragment ions which provide useful information for the structural characterization of biomolecules. Different fragmentation strategies result in different mass spectra for the same molecule and thus provide distinct features. Charge carriers play important roles in determining the dissociation pathways of the target precursor ions. The use of various transition metals ions as charge carriers of glycopeptide and glycan might provide additional structural information and needs to be investigated. A 9.4T SolariX FTICR mass spectrometer was used for collision-induced dissociation (CID) of glycopeptide and glycan. Group IIB metal ions, including Zn2+ , Cd2+ and Hg2+ , were used as charge carriers. Glycopeptide NLTK-M5 G2 and glycan G1F were used as the model systems. For Zn2+ - and Cd2+ -adducted species, cross-ring cleavages, glycosidic cleavages and cleavages along the peptide backbone could be obtained. There is a high degree of similarity in their CID spectra with that of Mg2+ ion-adducted glycopeptide species. For Hg2+ -adducted species, only glycosidic cleavages were observed in high abundance. The formation of doubly-charged ions (M2+ ) and a series of [f-H]+ fragments indicated unique dissociation pathways for Hg2+ -adducted glycopeptide. Zn2+ and Cd2+ -adducted glycopeptide species produced similar dissociation CID spectra, whereas Hg2+ -adducted species produced significantly different CID spectra. Similar CID dissociation features were also observed for Group IIB metal ions adducted glycan species. These results demonstrated that different metal ions might be used to tune the dissociation behaviors of glycopeptides and glycans.

Continuum Modelling As Tool for Optimizing the Cell Design of Magnesium Batteries

Magnesium-based next-generation batteries are of great interest since magnesium is not only very abundant, which allows economic and sustainable applications, but also less prone to dendrite formation than many other metals. Together with the bivalency of the magnesium cations the resulting possibility to safely use a metal anode enables batteries with high specific capacities.However, for a successful commercialization of magnesium batteries there are still some challenges to overcome. The high charge density of the bivalent cation causes strong coulomb interactions with anions and solvent molecules. Therefore, magnesium salts are prone to form ion pairs and bigger clusters – especially at high concentrations, which may adversely affect the transport in the electrolyte and the electrochemical reaction at the electrode.[1] Moreover, energetic barriers for desolvation and solid-state diffusion of the double-charged magnesium ion are usually very high, which can have a crucial impact on the battery performance. Former can significantly hinder the electron-transfer reaction,[2] whereas latter makes the choice of suitable cathode materials very challenging.Consequently, a good understanding of the limiting processes in rechargeable magnesium batteries is key to develop novel high-capacity / high-voltage cathode materials. For instance, it is well-known that the morphology of an intercalation material can strongly influence the battery performance and smaller particles as well as thinner electrodes are common strategies for avoiding adverse effects of transport limitations. However, high mass loadings as well as suitable separators are still essential bottlenecks for commercialization of magnesium-ion batteries.Up to date Chevrel phase (CP) Mo6S8 is considered as benchmark intercalation cathode and Mg[B(hfip)4]2 / DME is seen as most promising chloride-free magnesium electrolyte.[3,4] In our contribution we carefully study this model system of a magnesium-ion battery to get a better understanding of how to overcome undesired limitations. Therefore, we present a newly-developed continuum model, which is able to describe the complex intercalation process of magnesium cations into a CP cathode. The model considers not only the different thermodynamics and kinetics of the two intercalation sites of Mo6S8 and their interplay but also the impact of the desolvation on the electrochemical reactions and possible ion agglomeration. The parameterization and validation of the model is based on DFT calculations and experimental data. Different kind of (transport) limitations and their impact on the battery performance are studied in detail. All in all, the combination of different modelling techniques with experimental measurements provides important insights into the operation of magnesium ion batteries and enables an optimization of the cell design. Acknowledgements This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 824066 (E-MAGIC). Furthermore, this work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm-Karlsruhe) and was funded by the German Research Foundation (DFG) under Project ID 390874152 (POLiS Cluster of Excellence). The simulations were carried out at JUSTUS 2 cluster supported by the state of Baden-Württemberg through bwHPC and the German Research Foundation (DFG) through grant No INST 40/575-1 FUGG. References Drews, T. Danner, P. Jankowski et al., ChemSusChem, 3 (2020), 3599-3604.Drews, P. Jankowski, J. Häcker et al., ChemSusChem, 14 (2021), 4820-4835.Aurbach, Z. Lu, A. Schlechter et al., Nature, 407 (2000), 724-727.Zhao-Karger, R. Liu, W. Dai et al., ACS Energy Lett. 3 (2018), 2005-2013.

The Current State-of-the-Art Identification of Unknown Proteins Using Mass Spectrometry Exemplified on De Novo Sequencing of a Venom Protease from Bothrops moojeni.

(1) Background: The amino acid sequence elucidation of peptides from the gas phase fragmentation mass spectra, de novo sequencing, is a valuable method for the identification of unknown proteins complementary to Edman sequencing. It is increasingly used in shot-gun mass spectrometry (MS)-based proteomics experiments. We review the current state-of-the-art and use the identification of an unknown snake venom protein targeting the human tissue factor (TF) as an example to describe the analysis process based on manual spectrum interrogation. (2) Methods: The immobilized TF was incubated with a crude B. moojeni venom solution. The potential binding partners were eluted and further purified by gel electrophoresis. Edman degradation was performed to elucidate the N-terminus of the 31 kDa protein of interest. High-resolution MS with collision-induced dissociation was employed to generate peptide fragmentation spectra. Sequence tags were deduced and used for searches in the NCBI and Uniprot databases. Protein matches from the snake species were further validated by target MS/MS. (3) Results: Sequence tag D [K/Q] D [I/L] VDD [K/Q] led to a snake venom serine protease (SVSP) from lancehead B. jararaca (P81824). With target MS/MS, 24% of the SVSP sequence were confirmed; an additional 41% were tentatively assigned by data-independent MS. Edman sequencing provided information for 10 N-terminal amino acid residues, also confirming the match to SVSP. (4) Conclusions: The identification of unknown proteins continues to be a challenge despite major advances in MS instrumentation and bioinformatic tools. The main requirement is the generation of meaningful, high-quality MS peptide fragmentation spectra. These are used to elucidate sufficiently long sequence tags, which can subsequently be submitted to searches in protein databases. This basic method does not require extensive bioinformatics because peptide MS/MS spectra, especially of doubly-charged ions, can be analysed manually. We demonstrated the procedure with the elucidation of SVSP. While de novo sequencing quickly indicates the correct protein group, the validation of the entire protein sequence of amino acid-by-amino acid will take time. Reasons are the need to properly assign isobaric amino acid residues and modifications. With the ongoing efforts in genomics and transcriptomics and the availability of ever more data in public databases, the need for de novo MS sequencing will decrease. Still, not every animal and plant species will be sequenced, so the combination of MS and Edman sequencing will continue to be of importance for the identification of unknown proteins.

Application of Design of Experiments to the Analysis of Fruit Juice Deacidification Using Electrodialysis with Monopolar Membranes.

Despite the beneficial health effects of fruit juices, the high content of organic acids and low pH of some of them limit their consumption. The aim of this work was to study the deacidification of fruit juices using electrodialysis (ED) with monopolar membranes. Aqueous solutions of citric acid were used in ED deacidification experiments following a factorial design with citric acid concentration and electric current varying in the ranges of 5–25 g/L and 0.5–1 A, respectively. The design runs were characterized by a constant Faraday efficiency of 0.37 ± 0.03, suggesting that the triple-charged citrate ion (Cit3−) carried the electric charge through the anionic membranes. During deacidification, the pH increased in agreement with the decreasing concentration of the acid. Deacidification of pineapple juice or pineapple juice enriched with 20 g/L of citric acid using ED led to similar values of the Faraday efficiency, confirming that Cit3− is the main ion migrating through the anionic membrane. However, the decrease in titratable acidity during ED treatment was accompanied by a decrease in pH. Such behavior, already reported, was explained by considering proton generation during the transformation of the single (H2Cit−) and double-charged (HCit2−) citrate ions into the triple-charged ion (Cit3−) when entering the anionic membrane.

Carbon Quantum Dots' Synthesis with a Strong Chemical Claw for Five Transition Metal Sensing in the Irving-Williams Series.

Carbon quantum dots (CQDs) are an excellent eco-friendly fluorescence material, ideal for various ecological testing systems. Herein, we establish uniform microwave synthesis of the group of carbon quantum dots with specific functionalization of ethylenediamine, diethylenetriamine, and three types of Trilon (A, B and C) with chelate claws -C-NH3. CQDs’ properties were studied and applied in order to sense metal cations in an aquatic environment. The results provide the determination of the fluorescence quench in dots by pollutant salts, which dissociate into double-charged ions. In particular, the chemical interactions with CQDs’ surface in the Irving–Williams series (IWs) via functionalization of the negatively charged surface were ascribed. CQD-En and CQD-Dien demonstrated linear fluorescence quenching in high metal cation concentrations. Further, the formation of claws from Trilon A, Trilon B, and C effectively caught the copper and nickel cations from the solution due to the complexation on CQDs’ surface. Moreover, CQD-Trilon C presented chelating properties of the surface and detected five cations (Cu2+, Ni2+, Ca2+, Mg2+, Zn2+) from 0.5 mg/mL to 1 × 10−7 mg/mL in the Irving–William’s series. Dependence was mathematically attributed as an equation (ML regression model) based on the constant of complex formation. The reliability of the data was 0.993 for the training database.

Aromaticity of Heterocirculenes

This review summarizes the results on the aromaticity of a series of synthesized and hypothetical neutral heterocirculene molecules and their double charged ions. The aromaticity of heterocirculenes is a direct reflection of their electronic structure responsible for the specific optoelectronic and photophysical properties. We show how the presence of a heteroatom in the outer macrocycle affects the aromaticity of hetero[8]circulenes. In addition, we also describe the change in aromaticity and strain energy for a series of the “lower” (n < 8) and “higher” (n > 8) hetero[n]circulenes. It was demonstrated that the loss of planarity with increased strain leads to an increased antiaromaticity of the lower hetero[n]circulenes, whereas higher hetero[n]circulenes demonstrate a more pronounced aromatic nature because of the small departure from planarity of each heteroarene ring in hetero[n]circulene molecule. Finally, we discuss the aromatic nature of the first examples of π-extended hetero[8]circulenes.

Numerical Simulation of Multispecies Vacuum Arc Subjected to Actual Spatial Magnetic Fields

A three-dimensional (3-D) model for multispecies vacuum arc considering ionization and recombination process has been built in this article. With the model, the arc behaviors and species characteristics subjected to actual spatial magnetic fields of cup-shaped axial magnetic field (AMF) contact and transverse magnetic field-axial magnetic field (TMF-AMF) contact are investigated and compared. Furthermore, the validity of the model is verified by comparing with the experiments. Simulation results show that contact structures affect the species distributions of the arc by changing magnetic field and current density distributions. More triple charged ions are generated through ionization under higher electron temperature so that the triple charged ions gather where current constricts. The heat flux density is large in the current contraction region, where the contribution from triple charged ions is large as well. Spatial magnetic field distribution affects the Lorentz force acting on ion components. The force distribution is relatively uniform and the species are subject to inward force on the arc edge under cup-shaped AMF contact. For TMF-AMF contact, the double charged ions are subject to the force pointing to the TMF contact arms, whereas the triple charged ions are subject to the force pointing to the arc center. In addition, the consideration of arc species can improve the accuracy of the simulation results of the heat flux distribution, leading to a good agreement of the erosion condition between experiments and simulation.

Novel high throughput green UPLC-MS/MS methods for determination of desmopressin with special sample handling

Objectives of present investigation were to develop novel high throughput green UPLC-MS/MS methods for quality control of desmopressin formulations. Two liquid chromatographic methods: Method-I based on isocratic elution and method-II based on gradient elution were developed and validated. Methods were green, since less amount of organic solvent (≤75 ​μL, per sample run time) was utilized in mobile phase. Mobile phase (0.1% formic acid in ACN, and in water), flow rate was 300 ​μL/min. Desmopressin retention time and sample run time for Method-I were 0.59 and 1.0 ​min, respectively. Retention time and sample run time for method-II were 2.03 and 2.5 ​min, respectively. Double charged ions [M ​+ ​2H]2+ of desmopressin (m/z 535.33 ​> ​120) were monitored in multi-reaction monitoring mode. Desmopressin was directly analyzed in water samples. Calibration curves were prepared between 50 and 600 ​ng/mL. The values of r2 were 0.999. Assay and dissolution study of desmopressin formulation was successfully performed using these methods. Desmopressin was found to adsorb or react with different type of materials while handling. The specific filters (Chromafil® Xtra PTFE-45/25 0.45 ​μm, syringe filter) and tubes (glass tubes or Neutral graduated micro test tubes) were used for handling desmopressin samples.

Glycoform analysis of intact erythropoietin by MALDI FT-ICR mass spectrometry

Recombinant human erythropoietin (EPO) is a complex therapeutic glycoprotein with three N- and one O-glycosylation sites. Glycosylation of EPO influences its safety and efficacy and is defined as a critical quality attribute. Thus, analytical methods for profiling EPO glycosylation are highly demanded. Owing to the complexity of the intact protein, information about EPO glycosylation is commonly derived from released glycan and glycopeptide analysis using mass spectrometry (MS). Alternatively, comprehensive insights into the glycoform heterogeneity of intact EPO are obtained using ESI MS-based methods with or without upfront separation of EPO glycoforms. MALDI MS, typically performed with TOF mass analyzers, has been also used for the analysis of intact EPO but, due to the poor glycoform resolution, has only provided limited glycoform information. Here, we present a MALDI FT-ICR MS method for the glycosylation profiling of intact EPO with improved glycoform resolution and without loss of sialic acid residues commonly observed in MALDI analysis. Three EPO variants were characterized in-depth and up to 199 glycoform compositions were assigned from the evaluation of doubly-charged ions, without any deconvolution of the mass spectra. Key glycosylation features such as sialylation, acetylation, and N-acetyllactosamine repeats were determined and found to agree with previously reported data obtained from orthogonal analyses. The developed method allowed for a fast and straightforward data acquisition and evaluation and can be potentially used for the high-throughput comparison of EPO samples throughout its manufacturing process.

X-ray induced ion desorption from transition metal oxalates

Mass-spectrometric analysis of a number of atomic, molecular and double-charged ions desorbed from the surface of Mn, Co, Ni and Cu oxalate hydrates under Mg Kα X-ray irradiation was performed. The yield of desorbed ion species was found to steadily increase across the series of oxalates from MnC2O4·2H2O to CuC2O4·xH2O, exhibiting an inverse dependence on the –OCO–Me–OCO– bonds strength. Analysis of X-ray induced ion desorption from the surface of CoC2O4·2H2O annealed at different temperatures was demonstrated to be useful in studying compositional and structural alterations occurring in the topmost surface layer of the oxalate during the process of its thermal decomposition. The temperature dependences of the yield of characteristic ions were shown to be capable of discerning the dehydration and decomposition stages in this process. The probability of desorption and survival of different ions exhibited different dependence on the bonding and structural characteristics of the oxalates. The obtained results are compared with data provided by TG/DTA coupled with mass spectrometry and XPS techniques. Possible mechanisms of X-ray induced ion desorption from oxalates are discussed.

Small lithium-chloride clusters: Superalkalis, superhalogens, supersalts and nanocrystals.

In the present paper, the results of the theoretical investigation of the small lithium-chloride clusters are reported. The geometrical structures, electronic and thermodynamic stability of superalkalis, superhalogens, and their single and double charged ions are obtained using efficient and accurate quantum chemistry methods. Further, low-lying isomers of the Lin Cln ( ) clusters and their stability parameters are calculated. Two ways of formation of the Lin Cln clusters, polymerization of LiCl fragments and combination of superalkalis and superhalogen clusters, are compared. By examination the lattice energy and the average Li-Cl bond length in rectangular Lin Cln ( ) clusters, it was concluded that already 50 LiCl are enough to mostly resembles the structure and stability of the bulk LiCl.

Application of ICP-MS Method in Environmental Field

ICP-MS is a new technology for environmental monitoring and analysis. This article summarizes the characteristics of ICP-MS and its application in the analysis of environmental samples such as soil and water, and summarizes mass spectrometry interference factors such as isobaric, oxide, double charge, and polyatomic ions, with a view to future ICP-MS.