Ionization Electron Research Articles

Electron transfer efficiency in liquid xenon across THGEM holes

Dual-phase liquid-xenon time projection chambers (LXe TPCs) deploying a few tonnes of liquid are presently leading the search for WIMP dark matter. Scaling these detectors to 10-fold larger fiducial masses, while improving their sensitivity to low-mass WIMPs presents difficult challenges in detector design. Several groups are considering a departure from current schemes, towards either single-phase liquid-only TPCs, or dual-phase detectors where the electroluminescence region consists of patterned electrodes. Here, we discuss the possible use of Thick Gaseous Electron Multipliers (THGEMs) coated with a VUV photocathode and immersed in LXe as a building block in such designs. We focus on the transfer efficiencies of ionization electrons and photoelectrons emitted from the photocathode through the electrode holes and show experimentally that efficiencies approaching 100% can be achieved with realistic voltage settings. The observed voltage dependence of the transfer efficiencies is consistent with electron transport simulations once diffusion and charging-up effects are included.

Theoretical study of physisorption of tosylate on AU10, AU15 and AU18 surfaces utilizing DFT approach

Charge transfer from organic nanomaterial to the coinage metal surfaces occur as a result to the physisorption physisorption phenomena. Physisorption plays a major role in many applications. A set of properties such as, molecular geometries, contour density maps, electrostatic potentials (ESPs), infrared spectra (IR), electronic states, HOMO and LUMO energies, Energy gaps (Eg), ionization potential (I.P), electron affinity (E.A),dipole moment, polarizabilities , average polarizability , symmetry and density of states by using Gaussian 09 software package algorithms were investigated at LANL2DZ, B3LYP and the ground state energy of (Au10-OTS) , (Au15) , (Au15-OTS), (Au18) and (Au18-OTS) , but the structure of (Au10) has been submitted at LANL2MB,B3LYP basis sets. The research study physisorption phenomena from the organic nanomaterial to sylate (OTS) to the coinage metal surface (gold surfaces), also the research concentrate if charge transfer procedure gets at the surface. Physisorption phenomena and charge transfer procedure that happen at the surface can be known throughout some properties such as the closed energy contour maps, electrostatic potentials, symmetry and density of states. Electronic states and energy gap property have been studied in this research to recognize importance of the geometrical structures in the electronic devices and the different electronic applications in different branch of knowledges. The research had the ionization potential and electron affinity credits to demonstrate if the geometrical structure will behave as a donor or an acceptor because the ionization energy demonstrate ability of the geometrical structure to donate the electrons in an interaction, but the electron affinity describes the capacity of the geometrical structure to accept electrons in an interaction.

Effects of substitution and conjugation on photophysical properties of ESIPT-based fluorophores with the core of 4-aminophthalimide

4-Aminophthalimide is a highly fluorescent signaling unit with excellent photophysical properties and wide application foregrounds. Based on this, a range of theoretical investigations are conducted on the fluorescent probe (E)-5-((2-hydroxybenzylidene) amino) isoindoline-1, 3-dione (HID) with the core of 4-aminophthalimide using density functional theory (DFT) and time-containing density functional theory (TD-DFT) methods in this paper. The optimized configurations, vertical excitation and emission energies, electronic characteristics and excited-state intramolecular proton transfer (ESIPT) behaviors of the probe HID are discussed in detail. Furthermore, to enhance the luminescent properties of HID, five novel compounds have been designed based on the structure of HID by introducing amino, methoxy and naphthalene groups (–NH2, –OMe and C10H8). Our work thoroughly explores how the property and position of substituents and conjugation affect photophysical characteristics and ESIPT processes. We find that the ESIPT dynamics can be modulated by the substitution and conjugation effects. Specifically, the introduction of amino and methoxy groups at the ortho-position and the introduction of the naphthalene group promote the ESIPT behavior of HID1, whereas the introduction of amino and methoxy groups at the meta-position exhibits the contrary impact. Therefore, we boldly infer that the introduction of electron-donating groups in the ortho-position and the introduction of the conjugated group make the ESIPT process more effortless to occur, whereas the introduction of substituents with opposing natures in the meta-position makes the ESIPT process more difficult to occur. In addition, the ionization potentials (IP), electron affinities (EA) and reorganization energies (λh and λe) of molecules are calculated to assess their potential as luminescent materials. Our work not only reveals the luminescence and ESIPT mechanism of the probe HID1, but also proposes to modulate the ESIPT process through the substitution and conjugation effects. In particular, the designed molecules have better photoelectric properties as a result of their red-shifted absorption and fluorescence spectra, smaller energy gaps, larger transferred charges and greater charge transferred distances, which offers some valuable ideas for the experimental development of more efficient organic luminescent materials with ESIPT properties.

Theoretical study of electronic structure and ionization spectrum of γ-pyrone

The electronic structure and ionization spectrum of γ-pyrone (4 H -pyran-4-one) were studied using the third-order algebraic-diagrammatic construction method for a one-particle Green’s function [IP-ADC(3)] and a number of other high-level quantum chemical methods. The results of the calculations are used to interpret the recently obtained photoelectron spectra. A number of new assignments are proposed concerning the nature of the photoelectron maxima of γ-pyrone above 12 eV, where, according to our calculations, there is a significant violation of the single-electron ionization picture due to electron correlation effects. The results obtained significantly change the interpretation of the spectrum available in the literature.

An overview of conceptual-DFT based insights into global chemical reactivity of volatile sulfur compounds (VSCs)

Volatile sulfur compounds (VSCs) are highly volatile and most frequently associated with oral malodor. The odor quality is associated with the size and shape of the molecule along with stability, hydrogen bonding, extended d-shell electronic behavior, and complicity of d-shell bonding. Chemical reactivity descriptors of VSCs, such as chemical hardness (η), softness (σ), chemical potential (μ), electrophilic index (ω), and electronegativity (χ) are computed at B3LYP/Aug-cc-PVTZ level of theory from the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the light of Koopmans’ approximation. Furthermore, the global reactivity parameters are evaluated from the vertical ionization potential (IP) and electron affinity (EA) to support the results of Koopmans’ theorem. These reactivity parameters offer a quantitative measure of the electronic structure and chemical properties of VSCs, offering insights into their stability, reactivity, and interaction with other molecules. A Python-based application is provided for the rapid calculation of these parameters (GitHub: Link).

Self-assembly of macrocyclic oligofurans to create novel organic nanotubes through π–π stacking: a computational study

ABSTRACT In this manuscript, the potential utility of 6CF macrocyclic oligofuran is theoretically investigated to create novel nanotubes. The energetic, electronic, structural and topological properties of π-stacked systems are examined at B3LYP/6-31 + G(d), wB97XD/6-31 + G(d) and M06-2X/6-31 + G(d) levels of theory. The findings indicate that the self-assembly of 6CF macrocyclic oligofurans can be considered to create organic nanotubes through π–π stacking. The strength and nature of π-π interactions are examined using the atoms in molecules (AIM) approach. Meaningful relationships are obtained between stability, electronic properties and the number of stacked π-conjugated macrocyclic oligofurans. The stability and polarisability of π-stacked systems are amplified by increasing number of macrocycles. Reverse behaviours are found for the values of band gap, electronic chemical potential and first ionisation energy.

Investigating the Performance of Newly Designed Benzothiophene‐4,8‐Dione‐Based Dyes for Dye‐Sensitized Solar Cells

This research analyzes newly designed benzo1,2‐b:4,5‐b'dithiophene‐4,8‐dione‐based electron–hole transport dyes (BDD1‐BDD5), focusing mainly on their electronic and photovoltaic parameters. The calculations are performed using density functional theory with the M‐06X/6‐31G+(d,p) level of theory. Their highest occupied molecular orbital energies (EHOMO) range from −5.46 to −2.58 eV, while their lowest occupied molecular orbital energies (ELUMO) to range from −0.32 to −1.31 eV, with energy gaps (Egaps) of 2.67 to −5.88 eV. Their photovoltaic parameters show light harvesting efficiency (LHE) ranging from 0.84 to 0.93 eV, open‐circuit voltage (Voc) ranging from 0.88 to 1.45 eV, fill factor (FF) ranging from 0.883 to 0.9117, short‐circuit current (Jsc) ranging from 29.22 to 37.71 mA cm−2, and maximum incident power (Pmax) ranging from 24.01 to 39.92 W with maximum absorbance (λmax) ranging from 390 to 557 nm. Their range of global chemical reactivity parameters, such as ionization potential (IP, 2.58–5.46 eV), electron affinity (EA, −0.25–0.32 eV), electronegativity (x, 1.25–2.61 eV), global hardness (η, 1.33–2.94 eV), electrophilicity index (0.17–0.38 eV), and softness (σ, 0.18–0.45 eV), provides insights into the stability, reactivity, electron transfer capabilities, and planarity of molecules. Their natural bond orbital analysis reveals transitions with perturbation energies ranging from 0.34 to 30.85 K cal mol−1. These findings provide valuable insights into their properties and potential applications, particularly in photovoltaics as organic dyes.

Sulfur Oxidation State and Substituents Influenced Multifunctional Organic Luminophores in BTP Core for OLEDs: A Computational Study on RTP, TADF Emitter and Sensitizer.

The exploration of triplet excitons in thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) molecules has become a subject of significant attention and interest in recent studies. This study employed density functional theory (DFT) and time-dependent DFT theoretical methods to delve into the intricate relationship between the molecular structure and properties of molecules designed with the oxidation of sulfur atoms (S, SO, and SO2) in benzothiazinophenothiazine (BTP) core units. The calculations revealed that as the oxidation state of the sulfur atom increased, the BTP derivatives exhibited elevated ionization potentials (IPs), electron affinities (EAs), and triplet energies (ET), accompanied by reduced reorganization energies (λ), singlet energies (ES), and a S1-T1 energy gap (ΔEST). Additionally, the decrease in the exchange energy prompts a shift in the excited-state properties of molecules, transitioning them from hybridized local and charge transfer (HLCT) to charge transfer (CT) in the S1 state while maintaining their HLCT character in the T1 state. The sulfur oxidation process systematically decreases spin-orbit coupling magnitudes in the S1-T1 and T1-S0 pathways while increasing the KRISC rate, signifying a reduced propensity for phosphorescence radiative decay in oxidized molecules. Thorough investigations have explored the screening effect and orbital mixing of lone pair electrons in sulfur atoms, satisfying the desired criteria for a multifunctional RTP, TADF emitter and sensitizer.

Theoretical investigation of the vibrational and electronic properties of tetraphenylammonium and its boron, aluminum, gallium, carbon, silicon, germane, phosphorus and arsenic analogues

Tetraphenyl ammonium (Ph4N+ ) has long been considered a phantom ion due to the difficulty in synthesizing aryl ammonium compounds. Following the successful synthesis of Ph4N+ last year (2022), the equilibrium geometries of Ph4X (X = B-, Al-, and Ga- of group 13; C, Si, and Ge of group 14; and P+ and As+ of group 15) have been optimized using the B3LYP/6-31G(d,p) method with no symmetry constraints. According to the optimized structural data, Ph4N+ is considered the most sterically hindered molecule in this series of compounds, which reflects the difficulty of its synthesis. The calculated total energies of the Ph4X compounds reveal that their energies decrease down the group, and the cationic forms (group 15) are less energetic than their neutral (group 14) and anionic (group 13) counterparts. The optimized geometrical parameters were used to compute the UV–vis, IR, 1H NMR, and 13C NMR spectra of the nine terephenyl compounds. The frontier molecular orbital energies were used to determine ionization potentials, electron affinity, and other global reactivity descriptors of the nine Ph4X compounds. An accurate assignment of vibrational bands was made using the potential energy distribution (PED) method. The B3LYP/6-31G(d,p) method yielded good agreement with available experimental data for the molecules. The low HOMO-LUMO gaps suggest potential nonlinear optical properties of these compounds.

High-pressure xenon gas time projection chamber with scalable design and its performance around the Q value of 136Xe double-beta decay

Abstract We have been developing a high-pressure xenon gas time projection chamber (TPC) called AXEL (A Xenon ElectroLuminescence detector) to search for neutrinoless double-beta (0νββ) decay of 136Xe. The unique feature of this TPC is the electroluminescence light collection cell (ELCC), the part designed to detect ionization electrons. The ELCC is composed of multiple units, and one unit covers 48.5 cm2. A 180 L size prototype detector with 12 units, 672 channels, of the ELCC was constructed and operated with 7.6 bar natural xenon gas to evaluate the performance of the detector around a Q value of 136Xe 0νββ. The obtained FWHM energy resolution is $0.73 \pm 0.11\%$ at 1836 keV. This corresponds to $0.60 \pm 0.03\%$ to $0.70 \pm 0.21\%$ of the energy resolution at a Q value of 136Xe 0νββ. This result shows the scalability of the AXEL detector with the ELCC while maintaining a high energy resolution. Factors determining the energy resolution were quantitatively evaluated and the result indicates that further improvement is feasible. Reconstructed track images show distinctive structures at the endpoints of electron tracks, which will be an important feature in distinguishing 0νββ signals from gamma-ray backgrounds.

Dephasingless laser wakefield acceleration in the bubble regime

Laser wakefield accelerators (LWFAs) have electric fields that are orders of magnitude larger than those of conventional accelerators, promising an attractive, small-scale alternative for next-generation light sources and lepton colliders. The maximum energy gain in a single-stage LWFA is limited by dephasing, which occurs when the trapped particles outrun the accelerating phase of the wakefield. Here, we demonstrate that a single space–time structured laser pulse can be used for ionization injection and electron acceleration over many dephasing lengths in the bubble regime. Simulations of a dephasingless laser wakefield accelerator driven by a 6.2-J laser pulse show 25 pC of injected charge accelerated over 20 dephasing lengths (1.3 cm) to a maximum energy of 2.1 GeV. The space–time structured laser pulse features an ultrashort, programmable-trajectory focus. Accelerating the focus, reducing the focused spot-size variation, and mitigating unwanted self-focusing stabilize the electron acceleration, which improves beam quality and leads to projected energy gains of 125 GeV in a single, sub-meter stage driven by a 500-J pulse.

Development and validation of a UPLC-MS/MS method for determination of SYHA1807 in a first-in-human study.

Background: SYHA1807 is a novel lysine specific demethylase 1 inhibitor being developed for the treatment of small-cell lung cancer. Aim: This study aimed to establish a ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)/MS method for measuring SYHA1807 in human plasma, supporting its application in a first-in-human study. Methods: SYHA1807 was separated on an ACQUITY UPLC BEH® C18 Column (2.1×50mm, 1.7μm) after protein precipitation of plasma samples. Mass spectrometry analysis was performed with a Xevo TQS triple quadrupole mass spectrometer utilizing a positive electronic spray ionization source. The established method was fully validated according to bioanalytical guidelines. Results & conclusion: A rapid, specificand robust UPLC-MS/MS method was firstestablished for quantifying SYHA1807 and successfully applied in a first-in-human study.

Exploring the synthesis, structure, spectroscopy and biological activities of novel 4-benzylidene-1-(2-(2,4-dichloro phenyl)acetyl) thiosemicarbazide derivatives: An integrated experimental and theoretical investigation

BackgroundNovel α-amylase inhibitors play a crucial role in managing diabetes and obesity, contributing to improved public health by addressing these challenging and prevalent conditions. Moreover, the synthesis of anti-oxidant agents is essential due to their potential in combating oxidative stress-related diseases and promoting overall health. ObjectiveSynthesis of thoisemicarbazone derivatives of 2,4-dichlorophenyl acetic acid and to screened them for their biological activities. MethodThiosemicarbazone derivatives (4–13) were synthesized by refluxing 2,4-dichlorophenyl acetic acid with sulfuric acid in ethanol to get the ester (2), which was further refluxed with thiosemicarbazide to get compound (3). Finally, different aromatic aldehydes were refluxed with compound (3) in ethanol in catalytic amount of acetic acid to obtained the final products (4–13). Using modern spectroscopic techniques including HR-ESI-MS, 13C-, and 1H NMR, the structures of the created derivatives were confirmed. ResultsThe synthesized derivatives showed excellent to good inhibitory activity in the range of IC50 values of 4.95 ± 0.44 to 69.71 ± 0.05 µM against α-amylase enzyme when compared to standard drug acarbose (IC50 = 21.55 ± 1.31 µM). In case of iron chelating activity, these products showed potent activity better than standard EDTA (IC50 = 66.43 ± 1.07 µM) in the range of IC50 values of 22.43 ± 2.09 to 61.21 ± 2.83 µM. However, the obtained products also show excellent to good activity in the range of IC50 values of 28.30 ± 1.17 to 64.66 ± 2.43 µM against hydroxyl radical scavenging activity when compared with standard vitamin C (IC50 = 60.51 ± 1.02 µM). DFT used to calculate different reactivity factors including ionization potential, electronegativity, electron affinity, chemical softness, and chemical hardness were calculated using frontier molecular orbital (FMO) computations. The molecular docking studies for the synthesized derivatives with α-amylase were carried out using the AutoDock Vina to understand the binding affinities with active sites of the protein.

A Critical Analysis of Target Ionization and Projectile Electron Loss in Neutral– and Ion–Atom Collisions

Electron removal (target ionization and/or projectile electron loss) in neutral–atom collisions is theoretically studied for the impact of H0, He0 and He+ beams on noble gases (He, Ne and Ar). These reactions are investigated theoretically within the Continuum Distorted Wave-Eikonal Initial State model. New features have been included in the theoretical model: (i) a scaled projectile charge depending on its velocity and charge, (ii) a dynamic projectile-effective-charge depending on the momentum transfer, and (iii) a dynamic target-effective-charge depending on the kinematics of the emitted electron. The energy and angular spectra of emitted electrons from the target and from the projectile are calculated and compared with the available experimental data. Also, the influence of each one of the corrections on the resulting spectra will be studied.

Topological analysis and reactivity study of monomeric and dimeric forms of 2-methyl-4(1H)-quinolone: a computational study.

Quinolone derivatives have gathered major attention largely due to their wonderful biological activities. Quinolones are a class of molecules that are derived from quinolines and also extracted from natural sources. Most of these quinolones have significant medicinal properties ranging from antiallergenic and anticancer to antimicrobial activities. Some bacteria produce several 2-alkyl-4(1H)-quinolones. In past years, a variety of methods have been reported for the synthesis of quinolone derivatives. In this present work, structural, wave functional, and electronic properties of monomeric and dimeric forms of 2-methyl-4(1H)-quinolone are investigated. From the calculated binding energies, it was found that the formation of dimers is thermodynamically favorable. The analysis of reactivity parameters confirms that the keto form is more reactive than the enol form and keto-keto dimer is more reactive than compared to all monomeric and dimeric forms of our studied compound. Geometry optimizations of monomers and dimers of studied molecules were carried out using the B3LYP-D3(BJ)/ma-def2-TZVPP level of theory. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were calculated using the B3LYP/def2-TZVP level of theory. All DFT calculations were done with the ORCA 5.0.3 program. The reactivity parameters such as ionization potential, electron affinity, global hardness, global softness, electronegativity, chemical potential, and electrophilicity index were calculated. The nature of intermolecular interactions within the dimers was studied using topological analysis such as atoms in molecule (AIM) and reduced density gradient (RDG) surface analyses. To visualize the electron delocalization in the dimer electron localization function (ELF) and localized orbital locator (LOL) studies were also performed. The analyses such as AIM, RDG, ELF, and LOL were carried out by the multifunctional wavefunction analysis program Multiwfn 3.8.

Molecular Orbital Properties and Insulation Characteristics of Flaxseed Oil

This study aims to analyze the molecular orbital parameters of flaxseed oil (linum usitatissimum) and to measure the AC breakdown voltages at different electrode gaps with various rate of rises. AC breakdown voltages of flaxseed oil are measured at 1.0 and 2.5 mm electrode settings with 0.5 kV/s, 2.0 kV/s and 3.0 kV/s rate of rises, adhering to IEC and IEEE standards. UV-VIS (Ultraviolet–Visible) and FT-IR (Fourier Transform-Infrared) measurement tests carried out after breakdown voltage measurements reveals that the molecular structure of the oil remains stable against electrical discharges. The compounds of flaxseed oil are analyzed using GC-MS and it is determined that the oil mainly consists of seven triglycerides in accordance with the literature. In order to better understand the electrical behavior of these triglycerides, molecular orbital properties such as ionization potential, electron affinity and electron energy gap are analyzed employing Density Functional Theory (DFT) using B3LYP/6-311 + G(d,p) and B3PW91/6-311 + G(d,p) basis sets. The advantages of flaxseed oil such as AC dielectric strength, stability against breakdown mechanism, homogeneous molecular electrical characteristics of its compounds and antioxidant content make this oil as one of the potential natural ester alternatives to mineral oils in the power system industry.

Understanding the Reaction Chemistry of 1,1,3,3-Tetramethyldisilazane as a Precursor Gas in a Catalytic Chemical Vapor Deposition Process.

The reaction chemistry of 1,1,3,3-tetramethyldisilazane (TMDSZ) in catalytic chemical vapor deposition (Cat-CVD), including its primary decomposition on a heated W filament and secondary gas-phase reactions in a Cat-CVD reactor, was studied using 10.5 eV vacuum ultraviolet single-photon ionization and/or laser-induced electron ionization in tandem with time-of-flight mass spectrometry. It has been demonstrated that TMDSZ initially breaks down to form various species, including methyl radical (•CH3), ammonia (NH3), and 1,1-dimethylsilanimine (DMSA). The activation energies (Ea) for the formation of •CH3 and NH3 were determined to be 61.2 ± 1.0 and 42.1 ± 0.9 kJ mol-1, respectively, in the temperature range of 1400-2000 and 900-2400 °C. It was found that the formation of DMSA may have two different contributing routes, i.e., a concerted one (Ea = 33.6 ± 2.3 kJ mol-1) at lower temperatures of 900-1500 °C and a stepwise one (Ea = 155.0 ± 7.8 kJ mol-1) at higher temperatures of 2100-2400 °C. The secondary gas-phase reactions occurring in the Cat-CVD reactor environment were found to stem from two competing processes. The first one, free-radical short-chain reactions initiated by •CH3 formation and propagated by H abstraction reactions, is the dominating chemical process, producing many high-mass stable alkyl-substituted or silyl-substituted disilazane or trisilazane products via radical recombination reactions. Head-to-tail cycloaddition of unstable DMSA is the second contributing chemical process, which forms cyclodisilazane species. In addition, evidence was found for the conversion of NH3 into H2 and N2 in the Cat-CVD reactor.

Review of: "(Field effect nano transistors) Nano transistor electronic quantity and ionization potential)"

Review of: "(Field effect nano transistors) Nano transistor electronic quantity and ionization potential)"

NA62 liquid krypton purity monitor

A system for determining the purity of liquid krypton employed in the NA62 rare kaon decay experiment at CERN was developed based on the use of a time projection chamber. The attenuation of drifting ionization electrons from absorption of 511 keV gamma rays in liquid krypton was measured to estimate the purity. The setup was tested with krypton purified from commercial sources.

Molecular structure, physicochemical properties, impact of solvents ionization potential, electron occupancy, inhibition constant, and stabilization energy investigations of 4-acetamido benzoic acid

A novel heterocyclic organic compound, 4-Acetamido benzoic acid (4AMBA) had a wide range of applications in the field of drug discovery arena. The molecular structural stability conformation had been carried out using the Molecular Potential Energy Surface (MPES) scan with chosen suitable dihedral angle. For both the calculated and experimental procedures, the identifications of the chemical bonds of pertinent functional groups were investigated using spectral measurements (FT-IR and FT-Raman). The DFT/B3LYP/6–311++G(d,p) basis set, which is a highly compatible technique, was implemented to execute the quantum computational studies. Further, to enhance the molecular (inter and intra) interactions, reactivity regions between the atoms were performed using reactivity sites such as MEP, NBO, NLMO, NHO, and Hirshfeld surface analysis. In addition, the topological analysis for the various solvents and the electronic properties of the appropriate wavelength, the energy gap of the UV–Visible spectrum (both theoretical (various solvents) and experimental), FMO theories (HOMO and LUMO) energies and topological analyses were attained. The significant features that explain the biological behavior of the header composite were computed with the least possible binding energy using protein-ligand interactions with appropriate protein receptors, such as 1J1R, 1G1K, and 1J1Q.