Ion Emission Research Articles

Characterization of a single emitter passively fed electrospray ion source: part II-luminescence spectral analysis

Abstract Luminescence spectroscopy was used to examine the dynamics of propellant dissociation near the emitter tip of a single-emitter porous electrospray thruster loaded with the ionic liquid EMI-BF4. Luminescence spectra from CH, C2, CN, NH, BH, Hα, and Hβ were observed and confirmed by comparison with simulated spectra. Analysis of the CH (A 2Δ, v’ = 0) spectra yielded a rotational temperature 3082±30 K while the C2 (d 3Πg – a 3Πu) Swan system yielded rotational temperatures 6252±92 K and 5914±75 K for Δv = 0 and Δv = +1, respectively. Examination of the integrated spectral signals from acquired CH (A 2Δ), BH (A 1Π), and Hα spectra showed a strong correlation with measured extractor current in both positive and negative polarity mode. The evidence suggests the formation of these electronically excited species is due to dissociative excitation induced by high-energy collisions between emitted ions and propellant accumulated on the extractor orifice. A weak broadband signal was also observed and is likely due to dissociative excitation of the anion, BF4 -, leading to the formation of electronically excited BF2. Analysis of the neutral gas within the test chamber with a mass spectrometer confirmed the presence of BF2, providing strong evidence the observed broadband signal is the result of BF2.

Characterization of a single emitter passively fed electrospray ion source: part I - luminescence imaging analysis

Abstract Luminescence at the face of ionic liquid ion sources and nearby facility surfaces is a commonly reported radiative phenomenon that requires thorough examination. In this study, we present magnified images of a single emitter porous-media ionic liquid electrospray in profile, which provides spatial information on the origin of the luminescence. To determine what role facility interactions play in luminescence at the electrospray face, we varied the distance and material of a downstream beam target on which the ion plume terminated. The effect of applied emitter voltage on luminescence was also examined. Analysis of luminescence images and corresponding telemetry data demonstrate that the formation of luminescence near the emitter tip is not only a function of the surrounding test facility, but also dependent on the electrospray device, itself. The data also indicate the majority of luminescence observed within our experimental system is formed primarily from high-energy collisions between emitted propellant ions and propellant accumulated on the orifice of the extractor electrode.

Efficient Emission of Lanthanide Ion in Double Perovskite Nanocrystals Enabled by Synergistic Effect of Energy Level Modulation and Crystal‐Field Engineering

Efficient Emission of Lanthanide Ion in Double Perovskite Nanocrystals Enabled by Synergistic Effect of Energy Level Modulation and Crystal‐Field Engineering

Highly sensitive ratiometric luminescence manometers based on the multisite emission of Cr3+

In this work it has been shown how materials with multisite Cr3+ ion emission can be used for remote pressure sensing.

Ion Emission from Niobium Nanosecond Laser Plasma

Ion Emission from Niobium Nanosecond Laser Plasma

Indoor air concentrations of PM2.5 quartz fiber filter-collected ionic PFAS and emissions to outdoor air: findings from the IPA campaign.

Per- and polyfluoroalkyl substances (PFAS) are prevalent in consumer products used indoors. However, few measurements of ionic PFAS exist for indoor air. We analyzed samples collected on PM2.5 quartz fiber filters (QFFs) in 11 North Carolina homes 1-3 times in living rooms (two QFFs in series), and immediately outside each home (single QFF), for 26 ionic PFAS as part of the 9 months Indoor PFAS Assessment (IPA) Campaign. All targeted PFAS, except for PFDS and 8:2 monoPAP, were detected indoors. PFBA, PFHpA, PFHxA, PFOA, PFOS, and 6:2 diPAP were detected in >50% of indoor samples. PFHxA, PFOA, and PFOS had the highest detection frequency (DF = 80%; medians = 0.5-0.7 pg m-3), while median PFBA concentrations (3.6 pg m-3; DF = 67%) were highest indoors. Residential indoor air concentrations (sum of measured PFAS) were, on average, 3.4 times higher than residential outdoor air concentrations, and an order of magnitude higher than regional background concentrations. Indoor-to-outdoor emission rate estimates suggest that emissions from single unit homes could be a meaningful contributor to PFBA, PFOA, and PFOS emissions in populated areas far from major point sources. Backup QFFs were observed to adsorb some targeted PFAS from the gas-phase, making reported values upper-bounds for particle-phase and lower-bounds for total air (gas plus particle) concentrations. We found that higher concentrations of carbonaceous aerosol were associated with a shift in partitioning of short chain PFCAs and long chain PFSAs toward the particle phase.

Efficient circularly polarized luminescence from zero-dimensional terbium- and europium-based hybrid metal halides.

Zero-dimensional (0D) chiral hybrid metal halides (HMHs) with narrow-band circularly polarized luminescence (CPL) show considerable promise in three-dimensional displays. In this work, 0D (S/R-3MOR)3TbCl6 and (S/R-3MOR)3EuCl6 (abbreviated as S/R-TbCl, S/R-EuCl) enantiomers with characteristic rare-earth ion emissions are synthesized. S/R-TbCl and S/R-EuCl exhibit narrow-band green and red emissions with high photoluminescence quantum yields of (85-91)% and (48-52)%, respectively. These materials present distinct CPL signals with dissymmetry factors up to ±0.006 and ±0.009 for S/R-TbCl and S/R-EuCl, respectively. These chiroptical properties confer the potential for their applications in circularly polarized light-emitting diodes for future displays.

Long-term optical spectroscopy of B[e] star CI Cam in a quiet state

High-resolution optical spectra of the B[e] star CI Cam were obtained on arbitrary dates 2002–2023 using the 6-meter BTA telescope with the echelle spectrograph NES. The variability over time of the powerful emissions of Hα and He I profiles is found. For two-peaked emissions with «rectangular» profiles, the intensity ratio of blue-shifted and red-shifted peaks is V / R ≥ 1 , except one date. A decrease in the intensity of all two-peak emissions with «rectangular» profiles was revealed as they moved away in time from the 1998 outburst. The average radial velocity for emissions of this type for all observation dates varies in the range Vr(emis – d ) = –(50.8 – 55.7) + 0.2 km/s. The half-amplitude of the change (standard deviation) is equal to ∆Vr= 2.5 km/s. The velocity for single-peaked ion emissions (Si III, Al III, Fe III) differs little from the values of Vr(emis – d ) , but the measurement accuracy for these emissions is worse: the average error for different dates ranges from 0.4 to 1.3 km/s. The systemic velocity is assumed to be Vsys = –55.4 + 0.6 km/s according to the stable position of the forbidden emission [N II] 5754 Å. The position of single-peak emissions [O III] 4959 and 5007 Å is also stable: Vr([O III]) = –54.2 + 0.4 km/s. Emissions [O I] 5577, 6300, 6363 Å, [Ca II] 7291 and 7324 Å are absent from the spectra. Appearance of the emission near 4686 Å is an infrequent event, its intensity rarely exceeds the noise level. Only a wide asymmetric emission with an intensity of about 16% above the continuum was registered in the spectrum for 03.09.2015. Questions arise about the use of this emission to estimate the period of variability of the star and about localization of this feature in the CI Cam system. The photospheric absorptions of N II, S II, and Fe III with a variable position are identified.

Constrained Heterogeneous CoFe2O4/ZnO/PMS Fenton-Like System for Industrial Wastewater Remediation with Recyclability and Zero Metal Loss.

Although heterogeneous Fenton-like processes have attracted widespread attention in wastewater treatment, the mass leached active ions lead to secondary pollution and confuse the demarcation of reaction region. By constructing a constrained completely heterogeneous system and highlighting its reaction region concentrated within the slipping plane of particles, this work achieves efficient organic pollutants degradation without leaching of any free active metal components. Based on the Poisson-Boltzmann equation and electric double layer model, the specific existing of the constrained region is confirmed, and this neglected reaction region between solid interface and slipping plane in traditional heterogeneous Fenton-like reaction is clarified firstly. Due to the unique constrained property, this system demonstrates exceptional potentials application to natural water and actual industrial wastewater for its broad resistance to environmental interference. Furthermore, the alkalization aging process enables this system achieve catalyst recycle and zero metal ions emission with maintaining outstanding pollutants removing performance even in high-salt wastewater, exhibiting the superiority of the constrained completely heterogeneous system. This work demonstrated the important reaction region within slipping plane and provided a clearer boundary in heterogeneous Fenton-like system.

Constrained Heterogeneous CoFe2O4/ZnO/PMS Fenton‐Like System for Industrial Wastewater Remediation with Recyclability and Zero Metal Loss

Although heterogeneous Fenton‐like processes have attracted widespread attention in wastewater treatment, the mass leached active ions lead to secondary pollution and confuse the demarcation of reaction region. By constructing a constrained completely heterogeneous system and highlighting its reaction region concentrated within the slipping plane of particles, this work achieves efficient organic pollutants degradation without leaching of any free active metal components. Based on the Poisson‐Boltzmann equation and electric double layer model, the specific existing of the constrained region is confirmed, and this neglected reaction region between solid interface and slipping plane in traditional heterogeneous Fenton‐like reaction is clarified firstly. Due to the unique constrained property, this system demonstrates exceptional potentials application to natural water and actual industrial wastewater for its broad resistance to environmental interference. Furthermore, the alkalization aging process enables this system achieve catalyst recycle and zero metal ions emission with maintaining outstanding pollutants removing performance even in high‐salt wastewater, exhibiting the superiority of the constrained completely heterogeneous system. This work demonstrated the important reaction region within slipping plane and provided a clearer boundary in heterogeneous Fenton‐like system.

Strong field induced ion and electron emission from size-selected metal clusters

Strong field induced ion and electron emission from size-selected metal clusters

Enhanced proton acceleration using spiral-phase plasma mirrors

Abstract We present a method for generating intense vortex laser beams using spiral-phase plasma mirrors. These single-use micro-metric formations imprint a set amount of orbital angular momentum (OAM) to an arbitrary high power focusing beam. Using these beams, we irradiated ultrathin foils and measured the emission of ions from their back side. Utilizing a PW class laser, 5 J@45fs@2w resulting in an Intensity of 2×1020 W cm − 2 at spot focus, we observed an increase in the energy and numbers of these ions, compared to shots taken with reflection off flat plasma mirrors. A 45% increase in the proton numbers and a 35% increase in cutoff energy was observed. This is a major advance since the area of interaction and intensity are reduced due to the planar shape of the generated OAM laser. We review the available data-sets on laser ion acceleration using vortex beams, and conclude with a comparison to our findings.

Effects of terbium concentrations on the characteristics of Ga2O3 films

Abstract This study investigates the incorporation of Tb into Ga2O3 films and its influence on their structural, optical, and luminescent properties. Tb composition in Ga2O3 films was controlled by adjusting the Tb composition in the targets. X-ray diffraction analysis unveiled lattice expansion as Tb composition increased. Atomic force microscopy images depicted consistently smooth film surfaces across varying Tb compositions. Optical transmission spectra demonstrated high transmittance and direct bandgap transitions, with no notable alteration observed in the bandgap concerning Tb composition. Photoluminescence spectra exhibited characteristic Tb ion emission peaks, with intensities initially increasing before reaching a plateau, attributed to a balance between increased luminescent centers and deteriorated crystal quality. This study significantly enhances our understanding of Tb doping effects in Ga2O3 films and offers valuable insights for their application in optoelectronics.

Effect of the cation-to-anion mass ratio of ionic liquid on plume neutralization characteristics for novel electrospray thruster

Abstract The ionic liquid electrospray thruster (ILET), a promising technology for space electric propulsion, has been gaining attention due to its theoretical capability to operate without an external neutralizer, which is a key component for traditional ion thrusters. Some experiments have shown that the cation-to-anion mass ratio significantly affects the self-neutralization of thruster plumes, but further depth research is still needed. Therefore, numerical simulations of ion emission process both in uni-thruster and bi-thruster modes of ILETs are conducted using particle-in-cell method, to investigate the effect of the cation-to-anion mass ratio in ionic liquid on plume neutralization characteristics. In bi-thruster mode, the anions and cations are emitted simultaneously, while in uni-thruster mode, only anions or cations are emitted under the action of electric field force. Plume neutralization characteristics of four ionic liquid propellants, with different cation-to-anion mass ratio, in bi-thruster mode are obtained and compared to the uni-thruster mode. The results show that the plume profile morphology is significantly dependent on operating mode of the thruster and the cation-to-anion mass ratio of ionic liquid. Unlike the circular profile in uni-thruster mode, the plume in bi-thruster mode exhibit distortion with vertical stratification. The contours of the high-potential region in bi-thruster mode also distort, showing stratification and a V-shape, respectively, influenced by the mass ratio. Ion beam neutralization in bi-thruster mode is primarily achieved through the horizontal displacement of anion and cation beams, as well as their interactions. The cation-to-anion mass ratio influences the oscillation effects of the mass center in anion and cation clouds during neutralization, which in turn affects the neutralization effect. Ionic liquids with a significant mass ratio difference between cations and anions necessitate a longer time and greater distance for neutralization under identical conditions. These findings are instrumental for understanding the plume neutralization process and advancing the design of ILETs.

JWST/MIRI Detection of [Ne v], [Ne vi], and [O iv] Wind Emission in the O9 V Star 10 Lacertae

Abstract We report the detection of broad, flat-topped emission in the fine-structure lines of [Ne v], [Ne vi], and [O iv] in mid-infrared spectra of the O9 V star 10 Lacertae obtained with James Webb Space Telescope/Mid-Infrared Instrument. Optically thin emission in these high ions traces a hot, low-density component of the wind. The observed line fluxes imply a mass-loss rate of >3 × 10−8 M ⊙ yr−1, which is 1 order of magnitude larger than previous estimates based on UV and optical diagnostics. The presence of this hot component reconciles measured values of the mass-loss rate with theoretical predictions and appears to solve the “weak wind” problem for the particular case of 10 Lac.

Multi-Modal Luminescence Manometer Based on Cr3+ Ions Luminescence in Doped Li3Sc2(PO4)3

The necessity for precise pressure monitoring, coupled with the capability to monitor pressure values in real-time, is paramount. Consequently, recent years have witnessed a notable surge in research aimed at enhancing the quality of pressure sensors, as well as the exploration of novel technological solutions, owing to the rapid advancement in process automation. Sensors leveraging the luminescence response of luminophores show great promise, as evidenced by numerous studies showcasing the remarkable potential of luminescent thermometers. The luminescence characteristics of phosphors are influenced not only by temperature but also by pressure, presenting an opportunity to exploit this phenomenon in pressure sensing. To date, there have been relatively few studies reporting on luminescence-based pressure sensors, with most of them primarily focused on monitoring the spectral position of lanthanide ions emission bands, and less frequently of transition metal ions. The latter, however, due to their heightened sensitivity to variations in the strength of the crystal field affecting the transition metal ion, offer the prospect of designing highly sensitive luminescent pressure sensors. By exploring alternative approaches beyond those reliant solely on spectral shift of emission band, it becomes feasible to enhance both the precision and accuracy of pressure measurements. This assertion finds validation in the development of luminescent ratiometric pressure sensors, as evidenced by reported so far. [1,2]In line with this, we have proposed an optical pressure sensor based on the luminescence of Cr3+ ions in doped Li3Sc2(PO4)3 [2]. An invaluable advantage of the proposed sensor lies in its ability to operate in three distinct readout modes: (1) ratiometric, based on the LIR parameter, (2) relying on the spectral shift of the emission band, and (3) utilizing the variation in the average lifetime of the excited state. Each approach is grounded on the emission band associated with the 4T2 → 4A2 electronic transition of Cr3+ ions. Owing to the exceptional sensitivity of this transition to pressure-induced changes in the strength of the crystal field affecting Cr3+ ions, the proposed pressure sensor exhibits an exceptionally high sensitivity, e.g. more than 90% GPa-1 in the readout mode based on the average lifetime of the 4T2 state, which is a value surpassing any reported in the literature thus far. Additionally, we have demonstrated the feasibility of obtaining pressure readouts which are independent from temperature variations. Mentioned achievements positions Li3Sc2(PO4)3 as an outstanding candidate for application as a high-sensitivity luminescent pressure sensor in high-pressure environments.Acknowledgements: This work was supported by the National Science Center (NCN) Poland under project no. DEC-UMO - 2020/37/B/ST5/00164.[1] T. Zheng, M. Sójka, P. Woźny, I. R. Martín, V. Lavín, E. Zych, S. Lis, P. Du, L. Luo, M. Runowski, Adv. Optical Mater. 2022, 10, 2201055[2] M. Szymczak, J. Jaśkielewicz, M. Runowski, J. Xue, S. Mahlik, L. Marciniak, Adv. Funct. Mater. 2024, 2314068

Multielemental determination in lubricating oil samples by microwave-induced plasma optical emission spectrometry after extraction induced by emulsion breaking

Extraction induced by emulsion breaking (EIEB) was studied as a strategy for the determination of Al, Cr, Cu, Fe, Mg, Mn, Mo, Ni, and Pb in used lubricating oil via microwave-induced plasma optical emission spectrometry (MIP OES). No significant spectral and nonspectral interferences were observed in the developed method. These were evaluated as a function of the emission intensity of natural molecular species in the N2 plasma and different atomic and ionic emission lines. The time required for extraction was evaluated, and the best sensitivity for all the elements was obtained at 40 min of contact between the sample and the extraction solution in the presence of the surfactant. Doehlert matrix response surface methodology was employed to study the effects and interactions between the nitric acid (extractor) and surfactant (emulsifier) concentrations during sample preparation. The recommended conditions for 3.0 g of sample were as follows: 5.0 mL of extraction mixture consisting of 2.8 mol/L nitric acid and 3.0 % (v v−1) of the surfactant Triton X-114. The limits of quantification obtained were 2.9 (Al), 43 (Cr), 4.0 (Cu), 17 (Fe), 4.0 (Mg), 3.7 (Mn), 7.0 (Mo), 9.2 (Ni) and 45 (Pb) µg kg−1. The method developed was applied in the analyses of lubricating oil samples. The following concentration ranges (mg kg−1) were found: 2.5–106 (Al), 2.8–24.8 (Cr), 3.5–21.4 (Cu), 16.9–199 (Fe), 33.4–64.0 (Mg), 0.57–9.7 (Mn), 4.7–43 (Mo), 1.6–11.1 (Ni) and 2.0–12.6 (Pb).

Ionization chemistry in the inner disc: a combined treatment of ionic and thermionic emission and arbitrary grain size distributions

ABSTRACT In the inner regions of protoplanetary discs, ionization chemistry controls the fluid viscosity, and is thus key to understanding various accretion, outflow and planet formation processes. The ionization is driven by thermal and non-thermal processes in the gas phase, as well as by dust-gas interactions that lead to grain charging and ionic and thermionic emission from grain surfaces. The latter dust–gas interactions are moreover a strong function of the grain size distribution. However, analyses of chemical networks that include ionic/thermionic emission have so far only considered grains of a single size (or only approximately treated the effects of a size distribution), while analyses that include a distribution of grain sizes have ignored ionic/thermionic emission. Here, we (1) investigate a general chemical network, widely applicable in inner disc regions, that includes gas phase reactions, ionic and thermionic emission, and an arbitrary grain size distribution; (2) present a numerical method to solve this network in equilibrium; and (3) elucidate a general method to estimate the chemical time-scale. We show that (a) approximating a grain size distribution by an ‘effective dust-to-gas ratio’ (as done in previous work) can predict significantly inaccurate grain charges; and (b) grain charging significantly alters grain collisional time-scales in the inner disc. For conditions generally found in the inner disc, this work facilitates (i) calculation of fluid resistivities and viscosity; and (ii) inclusion of the effect of grain charging on grain fragmentation and coagulation (a critical effect that is often ignored).

Tailoring polythiophene nanocomposites with MnS/CoS nanoparticles for enhanced SERS detection of mercury ions in water

The excessive emission of heavy metal ions from industrial processes poses a serious threat to both the environment and human health. This study presents a novel approach using PTh-MnS/CoS NPs for the selective and sensitive detection of Hg2+ ions in water. Such detection is crucial for safeguarding human health, protecting the environment, and assessing toxicity. The fabrication method employs a simple and efficient chemical precipitation technique, combining polythiophene, MnS, and CoS NPs to create active substrates for SERS. The MnS@Hg2+ exhibits a distinct Raman shift at 938 cm−1, enabling specific identification and showing the highest responsiveness among the studied semiconductor substrates with a detection limit of only 1 nM. This investigation shows reliable and practical SERS detection for mercury ions. The RSD ranged from 0.49 % to 9.8 %, and recovery rates varied from 96 % to 102 %, showing selective adsorption of Hg2+ ions on the synthesized substrate.

Stochastic Emission in Passively Fed Single-Emitter Porous-Media Ionic Liquid Ion Sources

Ionic liquid ion sources are a promising form of efficient thrust for power- and mass-constrained satellites. Flight performance requirements necessitate large arrays of emitters; however, the fundamental behaviors of the ion emission process are obscured by the simultaneous operation of multiple emitters. One such behavior is the stochastic nature of Taylor cone formation and ion emission from the emitter. To examine these phenomena, a single-emitter electrospray using a conventionally machined porous borosilicate emitter cone was operated using the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate. Repeated performance curves of the same emitter, measuring the emitter and extractor electrode currents as a function of the emitter voltage, vary significantly between tests. Ion current density spatial distribution maps of the plume and time-resolved emitter current and plume current while retarding potential energy analyzer sweeps are also presented. High-speed current measurements on a collector plate downstream of a different single-emitter electrospray were collected to examine the variation in the onset delay time of the Taylor cone. The onset delay time decreased with increasing emitter voltage and was effectively eliminated using bipolar switching. In monopolar mode, the onset delay rate was not sensitive to changes in the emitter voltage switching frequency across the range of tested values.