Vacuum Phase Research Articles

Synergizing Machine Learning, Conceptual Density Functional Theory, and Biochemistry: No-Code Explainable Predictive Models for Mutagenicity in Aromatic Amines.

This study synergizes machine learning (ML) with conceptual density functional theory (CDFT) to develop OECD-compliant predictive models for the mutagenic activity of aromatic amines (AAs) with a fully No-Code methodology using a comprehensive data set of 251 AAs, Leave-One-Out-Cross-Validation (LOOCV), and three distinct data splits. Our research employs the GFN2-xTB method, known for its robustness and speed, to compute descriptors for procarcinogens and their activated metabolites in vacuum and aqueous phases. We evaluate the effectiveness of different theoretical definitions of electrophilicity within CDFT, namely, PSL, GCV, and CDP schemes, and the newly introduced Log QP descriptor to approximate Log P information. SPAARC, RandomTree, and JCHAID* ML methods were used to build explainable predictive models with highly robust internal validation (Avg. Correct Classifications = 76% and Avg. Kappa = 0.29) and external validation (Avg. Correct Classifications = 79% and Avg. Kappa = 0.33) metrics, and the results were compared to those of a two hidden layer Multilayer Perceptron. The results indicate that the second CDP definition for the electrophilicity in both vacuum and aqueous phases and also the newly presented Log QP descriptors are the most important ones for predicting the mutagenic activity of AA (namely ω+VacCDP2+, ω+AqCDP2+, and LogQP1+Vac, respectively). The results indicate that metabolic activation, aqueous solvent properties, and the CDP electrophilicity schemes and Log QP should be considered when building predictive models for the mutagenic activity of AA. This study offers a replicable, No-Code approach to QSAR research, making high-level ML and CDFT applications accessible to a broader audience. Future work will expand these methods to other compound families, enhancing predictive capabilities in the study of mutagenic activities and other biological phenomena.

Numerical and experimental investigation of the steam penetration in narrow channels during a dynamic steam sterilization cycle

The most challenging aspect of steam sterilization is the removal of all non-condensable gases (NCGs) from the autoclave. These gases prevent the effective killing of microorganisms, impairing the sterility of medical devices. Special cycles are performed to ensure the penetration of steam, even into the deepest passages. To better understand this process, numerical models were developed to determine the spatial distribution of steam within the chamber, including its penetration into narrow channels. These are the first models that can be used to accurately determine the flow within three-dimensional cavities during a dynamic sterilization cycle. To validate the model, an experiment was designed using direct tunable diode laser absorption spectroscopy at a wavelength of 1364 nm to measure the mole fraction of steam present at the end of an aluminum pipe at a temporal resolution of 1 s. This represents a pioneering application of this technique in the field of steam sterilization. This setup was designed for installation on any autoclave. Both simulation and experimental data exhibit good agreement over the entire pressure range (0.18–3.15 bar). The most interesting observation made during the study was the increase in the steam content at the end of the tube while a vacuum was generated. The numerical results show that the mole fraction of H2O increased from 0.53 to 0.63 over the course of a single vacuum phase. This phenomenon was attributed to a stronger diffusion effect combined with small pressure gradients during low pressures. This finding inspired the idea of taking the diffusion effect more into account when designing sterilization cycles in the future to make them more sustainable and effective. The presented methodologies and models represent an excellent basis for conducting more complex investigations in the future, such as those investigating the influence of condensation effects on steam penetration in cavities.

A test of strangeness quantum number conservation in proton-proton collisions

The study delves into the production of (multi-) strange hadrons in proton-proton collisions at LHC. Novel observables are proposed to distinguish between Epos4, based on core-corona separation between a thermalised QGP phase and a vacuum phase with global strangeness conservation, and Pythia 8.3, based on microscopic interactions between Lund strings that conserve strangeness locally. Correlations between a ϕ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\phi $$\\end{document} meson and (multi-)strange hadrons are shown to be an excellent discriminator between the two types of models.

Flow Structure and Periodic Processes in a Disc-Shaped Vortex Chamber of a Hydrodynamic Cavitator

Introduction. The essence of the acoustic – cavitation processes is that the liquid is passed through sound with a pressure at the wave surface of more than 3 bar that causes local breaks of the liquid in the vacuum phase of the wave and the collapse in the manometric phase. The opposite walls of each cavern in the collapse approach at a speed exceeding two speed of sound, due to which a high energy density is achieved at the meeting point, and what is especially valuable is the mutual transitions of energies from one form to another, unattainable under normal conditions, and, moreover, as inside cavitation area and near it. The novelty of the work is confirmed by the results of a periodic information and patent analysis, and by four patents received for inventions on the topic under consideration.Aim of the Study. The study is aimed at improving the acoustic-cavitation qualities of a disk-shaped vortex chamber used as a liquid whistle.Materials and Methods. In the study, there were used numerical modeling of flows in the FlowVision program, experimental determination of flow rates using a pitot tube, film method, removal of frequency response using SpectraPLUS 5.0, and visualization of flows and processes on optically transparent devices by the method of color indicators in stroboscopic lighting high-speed video shooting.Results. The mechanism of sound generation and noise in the flow transiting through the device has been found. The corrective effect of pump pulsations f = 300 Hz on the sound generation mechanism was revealed. The disc-shaped character of the device, which encloses the input flow in cross section from three directions, contributes to creating a more expressive acoustic signal, forming two conjugate torus vortices along the shell that ensures uniformity of the circumferential flow, attenuation of longitudinal high-frequency oscillations f = 200 kHz, and the creation of periodic zones of increased pressure along the shell. The concentrated tangential entrance to the device determines the central asymmetry of the flows in it and a number of processes that create acoustic noise.Discussion and Conclusion. The frequency of the useful acoustic signal in the vortex chamber is proportional to the speed of the transit flow, and the amplitude is proportional to the dimensions of the device. Along with the useful signal created by the interaction of the peripheral and input parts of the transit flow, noise of similar frequencies is created in the device. Other sources of noise generation are due to the presence of a concentrated tangential input. The formation of two conjugate torus vortices along the shell can be used as a means of controlling the process of interaction between parts of the transit flow. The disc-shaped vortex chamber combines the functions of sound generation and the ability to create a centrifugal field, which expands its technological capabilities.

Cosmological first-order vacuum phase transitions in an expanding anisotropic universe

We examine the anisotropy originated from a first-order vacuum phase transitions through three-dimensional numerical simulations. We apply Bianchi Type-I metric to our model that has one scalar field minimally coupled to the gravity. We calculate the time evolution of the energy density for the shear scalar and the directional Hubble parameters as well as the power spectra for the scalar field and the gravitational radiation although there are a number of caveats for the tensor perturbations in Bianchi Type-I universe. We run simulations with different mass scales of the scalar field, therefore, in addition to investigation of anisotropy via the shear scalar, we also determine at which mass scale the phase transition completes successfully, hence, neglecting the expansion of the Universe does not significantly affect the results. Finally, we showed that such an event may contribute to the total anisotropy depending on the mass scale of the scalar field and the initial population of nucleated bubbles.

Solvent effects and Raman enhancement during the adsorption of atrazine on pristine Ag, Au, Cu and mixed clusters

Investigation of the adsorption properties of a herbicide, atrazine (6-chloro-4-N-ethyl-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine) (CPD) with Ag, Au, Cu and their mixed clusters are presented using density functional theory (DFT) analysis. With metal clusters, it is found that CPD forms stable clusters, the drug-cluster complexation energy is maximum in CPD-Au2Cu (−38.69 and −45.79 kcal/mol) in vacuum and aqueous phase in comparison with other clusters. Dipole moment of the CPD-metal systems is higher than that of CPD. Clustering of CPD with metal cages enhances the Raman signals due to surface enhanced Raman scattering (SERS) activity. The exothermic processes and fluctuations in entropy during the processes were altered for all clusters as a result of CPD adsorption to the cages, indicating a change to a more ordered structure. Wavefunction based analysis indicated that there are significant non-covalent interactions (NCIs) between the system and the metal clusters.

Work function of the caesiated converter surface at the BATMAN Upgrade H− ion source at different operational scenarios

Since negative hydrogen ion sources for neutral beam injection (NBI) systems rely on the surface production of negative hydrogen ions, Cs is injected to lower the work function of the extraction electrode surface. The adsorbed Cs layers are affected by residual gases from the given non-UHV conditions as well as by reactive hydrogen species during plasma phases, which leads to a complex surface chemistry and the occurrence of temporal changes of the work function. To control the work function and get insight into its temporal dynamics, an absolute work function diagnostic has been developed for ion sources with which measurements can be performed in vacuum phases between pulses. The diagnostic is applied at the BATMAN Upgrade test facility, which is equipped with the prototype RF ion source for the ITER NBI. It is shown that the Cs conditioning of the ion source leads to a dramatic decrease in the work function to ultra-low values < 1.5 eV. First measurements after the application of 1000 s pulses indicate that the ultra-low work function layer is not stable upon long-term plasma exposure and it is revealed that high dynamics of the Cs surface properties are given right after the pulse.

Techno-Economic Evaluation on Solar-Assisted Post-Combustion CO2 Capture in Hollow Fiber Membrane Contactors

In this study, a novel system which integrates solar thermal energy with membrane gas absorption technology is proposed to capture CO2 from a 580 MWe pulverized coal power plant. Technical feasibility and economic evaluation are carried out on the proposed system in three cities with different solar resources in China. Research results show that the output capacity and net efficiency of the SOL-HFMC power plant are significantly higher than those of the reference power plant regardless of whether a TES system is applied or not. In addition, the CEI of the SOL-HFMC power plant with the TES system is 4.36 kg CO2/MWh, 4.45 kg CO2/MWh and 4.66 kg CO2/MWh lower than that of the reference power plant. The prices of the membrane, vacuum tube collector and phase change material should be reduced to achieve lower LCOE and COR values. Specifically for the SOL-HFMC power plant with the TES system, the corresponding vacuum tube collector price shall be lower than 25.70 $/m2 for Jinan, 95.20 $/m2 for Xining, and 128.70 $/m2 for Lhasa, respectively. To be more competitive than a solar-assisted ammonia-based post-combustion CO2 capture power plant, the membrane price in Jinan, Xining and Lhasa shall be reduced to 0.012 $/m, 0.015 $/m and 0.016 $/m for the sake of LCOE, and 0.03 $/m, 0.033 $/m and 0.034 $/m for the sake of COR, respectively.

Research on establishment of digital-twin system for intelligent control of cutting tools sintering process driven by data-model combination

In the manufacturing process of tungsten cemented carbide cutting tools, the changes in temperature, pressure and vacuum during the sintering process of the cutting tools can have a significant impact on the quality of the cutting tools. This effect is particularly significant in the vacuum sintering stage, so this paper focuses on cutting tools sintering in the vacuum stage. The cutting tools sintering process is carried out in a closed space in a sintering furnace with a complex internal structure. Therefore, it is extremely difficult to accurately predict the heating condition of the cutting tools in the furnace and monitor the sintering quality of the cutting tools. In this study, a digital twin system for the sintering process of cemented carbide cutting tools is proposed, which combines monitoring rolling data analysis and sintering quality prediction model. Firstly, the radiative thermodynamic model of cutting tools sintering temperature was established in this system. The model predicts the time-varying state of the heat distribution at any location in the furnace during the vacuum phase. Subsequently, based on the convolutional neural network, the mapping relationship between the sintering parameters and the grain size in the vacuum stage is constructed, and a dynamic evaluation model of cutting tools sintering quality is proposed. The model enables real-time prediction of sintering quality in the vacuum stage. The system realizes the prediction of the time-varying state of the sintering quality of the cutting tools. The digital twin system realizes the adaptive temperature control of the vacuum stage of cutting tools sintering based on the fuzzy control algorithm. The application of this system has increased the yield rate of cemented carbide cutting tools manufacturing to 98.9%. This breaks through the problem of timing modulation of cutting tools sintering quality in the vacuum stage of cutting tools sintering.

Modulation of lanthanide luminescence by carbamoylmethylphosphine oxide ligand: A theoretical study

The antenna capacity of Phenacyldiphenylphosphine oxide (Phenac), combining C=O and P=O donor groups was established by theoretical examination of its chromophore properties, binding ability to encapsulate and stabilize lanthanide complexes and potential to sensitize the EuIII and TbIII luminescence in Eu(Phenac)2(NO3)3(H2O) (1), Eu(Phenac)2(NO3)3 (2), Eu(Phenac)3(NO3)3 (3) and Tb(Phenac)2(NO3)3(H2O) (4) complexes in vacuum, solution and solid phase. The ligand-centered singlet and triplet excited state energies, the rates and lifetimes for the rival nonradiative (S1→T1,2 intersystem crossing (ISC)) and radiative and nonradiative S1→S0 and T1→S0 relaxation were predicted by means of DFT/TDDFT/ωB97XD calculations. Similar relaxation paths were found for all complexes. The absorbed energy by Sn > 1(π-π*) states relaxed to T1min by major ISC mechanism S1→T2→T1. The long radiative lifetime of S1→S0 due to n(p(C)(O))π-π*,p(P) character facilitated the forward ISC process. The environment, Phenac's number and LnIII size affect the T1 energy ∼0.1 eV. The calculated (Phenac→EuIII) energy transfer rates suggested the most likely T1 → 5D1/5D0 channels for a population of emitting metal-centered states. The small Φ of EuIII and larger luminescence of TbIII were discussed and explained. The importance of the P=O and C=O groups for the coordination ability and absorption properties of Phenac has been elucidated.

Vacuum-assisted and multi-cumulative trapping in headspace solid-phase microextraction combined with comprehensive multidimensional chromatography-mass spectrometry for profiling virgin olive oil aroma

In the present work vacuum (Vac) and multiple cumulative trapping (MCT) headspace solid phase microextraction (HS-SPME) were evaluated as alternative or combined techniques for the volatile profiling. A higher extraction performance for semi-volatiles was shown by all three techniques. Synergic combination of Vac and MCT showed up to 5-times extraction power for less volatile compounds. The hyphenation of said techniques with comprehensive two-dimensional gas chromatography (GC × GC) enabled a comprehensive analysis of the volatilome. Firstly, 18 targeted quality markers, previously defined by means of classical HS-SPME, were explored for their ability to classify commercial categories. The applicability of such markers proved to be limited with the alternative sampling techniques. An untargeted approach enables the selection of specific features for each technique showing a better classification capacity of the commercial categories. No misclassifications were observed, except for one extra virgin olive oil classified as virgin olive oil in 3 × 10 min Vac-MCT-HS-SPME.

Work function of titanium thin layers

The dependence of electron work function, Φ, on the thickness of Ti layers was investigated by making use of the Kelvin method under ambient conditions. Layers were produced by vacuum phase deposition and were analyzed by x-ray photoelectron spectroscopy and transmission electron microscopy. A quantum size effect was revealed finding work function to increase as the layer thickness, z, decreased below 4 nm. The extent of increase, ΔΦ, was understood in terms of a simple particle-in-a-box model arriving at the function ΔΦ=ℏ2π2/2mez2. This equation being free of any adjustable parameter, consisting only of the Planck constant and electron mass, seems to be a reasonable first approximation.

(Invited) Ionic Liquid Electrospray Ion Sources for Space Propulsion

The number of microspacecraft launched has significantly increased since 2013, and more than 300 nano/microsatellites (< 50 kg) were launched in 2017. Although some microspacecraft already have a propulsion system, a commonly used propulsion system is a cold-gas thruster, which has a low delta-v (a few 10s of m/s), and thus, high delta-v (> 1 km/s) thrusters are required for more advanced missions. One of the candidates for such thrusters is ion thrusters, which were already mounted on two 50 kg-class microsatellites and successfully operated in space. However, it is not easy to miniaturize ion thrusters so that they can be mounted on even 10 kg-class nanosatellites unless high-pressure gas-feeding systems are removed. Moreover, ion thrusters require electron sources to neutralize ion beams, which consume additional propellants and power. Since most recently launched microspacecraft are less than 10 kg, more compact thrusters are required. Ionic liquid electrospray ion sources are attractive devices for such electric propulsion, especially for microspacecraft. Electrospray thrusters typically consist of many emitters, an extractor electrode, and an accelerator electrode optionally. When a high voltage between the emitter and the extractor is applied, the ionic liquid is transported to the emitter tips, and a strong electric field deforms the ionic liquid into a conical shape known as a Taylor cone. When the force of the electric field is stronger than the surface tension pressure of the ionic liquid, ions evaporate directly from the liquid surface. The extracted ions are then accelerated by the potential difference between the emitter and extractor to produce the thrust. Since the ionic liquid is composed of only cations and anions without solvent, its vapor pressure is negligible; therefore, it can exist in the liquid phase in vacuum, simplifying the propellant feed system and reducing the size of the entire propulsion system. Moreover, the direct acceleration of ions without discharges can be possible, and no neutralizers are required, which also contributes to the power and size reduction together with high efficiency. The key component of electrospray thrusters is the emitter, where there are typically three types of structures: externally-wetted (or needle-shaped), internally-wetted (or capillary), and porous ones. Each has ion emission characteristics depending on the structure. Here, we have fabricated these three types of emitter structures with a wide range of scale: 1 to 100 micrometers. Using these emitters, we have conducted ion emission experiments and beam diagnostics. We obtained a high current density over a few 10 mA/cm2 with 1-micrometer scale emitters, a high current of approximately 1 mA with porous emitters, and a high efficiency with externally-wetted emitters. The emitter structures as mentioned earlier and experimental results will be presented at the conference site.

Surface evolution of Pt/MoO3/4H-SiC(0001) investigated by in situ near-ambient pressure X-ray photoelectron spectroscopy

Achieving effective Ohmic contact between SiC and metal electrodes remains a challenge due to the high Schottky barrier resulting from the large mismatch between the deep-lying valence band of SiC and Fermi level of metals. One promising approach to address this issue is to introduce a high-work-function interfacial layer between the metal and semiconductor. However, the interaction mechanisms of the inserted high-work-function interfacial layer between metal electrodes and the SiC substrate have been rarely studied systematically. In this work, layers of high-work-function molybdenum trioxide (MoO3) and platinum (Pt) were successively grown on the 4H-SiC(0001) surface via conventional physical vapour deposition (PVD). We investigated the chemical and electronic structure evolutions upon Pt deposition on MoO3/4H-SiC(0001) using in situ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and ultraviolet photoelectron spectroscopy (UPS). Subsequently, the evolutions of Pt/MoO3/4H-SiC(0001) system during annealing under ultra-high vacuum (UHV) or various gas phase environments (H2 and O2) were studied via in situ NAP-XPS and UPS. Our results reveal that Pt showed its thermal stability during the annealing process, while Mo presented its versatile chemical characteristics. These results depict a detailed chemical feature of the Pt/MoO3/4H-SiC(0001) system and help gain a better understanding about the impact of different environments on Pt/MoO3 interface.

Tunable Spatial Resolution of a Scanning Probe Microscopy (SPM) by an Efficient Cryosorption Pump

Scanning Probe Microscopy (SPM) is a useful instrument to study the surface topography of the sample at an atomic resolution. SPM system is sensitive to vibration and contamination on the surface, and therefore a vibration-free and clean environment are required to improve spatial resolution in Z-height. In this paper, a detailed new design of stand alone cost effective, vibration free activated carbon based cryosorption pump integrated and its detailed integration with SPM system is discussed. The efficiency of cryosorption pump depends on the radial temperature distribution, which was analysed using transient thermal analysis in Ansys software. The temperature profile obtained from the thermal simulation results reveals that a spiral wound copper mesh based partition surrounding the activated carbon in cryosorption pump improves the temperature distribution in the radial direction. The pump can operate with a maximum of 25 litres of Liquid nitrogen consumption and 4.5 hrs of continuous operation. The activated carbon was used as an adsorbent showed a hexagonal crystal structure from the X-Ray Diffraction (XRD) studies and its average pore size was obtained from by Brunauer-Emmett-Teller (BET) analysis was 0.34 nm. These tests were conducted to determine the effect on the pump-down characteristics of developed cryosorption pump. The improvement in spatial resolution was studied through detailed experimental analysis in Conductive Atomic Force Mode (CAFM) by Piezo Force Microscopy (PFM) which showed a 50 percent decrease of the current when imaged in a vacuum environment, phase and magnitude images showed the less distorted and clear visibility of the piezo domains. The magnetic interaction by Magnetic Force Microscopy (MFM) Q-factor was studied at the resonance frequency of 61.5 kHz. MFM showed that the Q-factor improved from 20 to 500 at 1E-3 mbar operating pressure. The drift of the MFM tip with respect to holding time showed a saturated Q-factor at 500. Non-contact mode by Atomic Force Microscopy (AFM) showed a spatial resolution enhancement of 0.89 nm.

BRST characterization of the broken phase observables of a confining complex theory

Some time ago we have introduced a route to provide confinement in the sense that particle excitations would appear from condensates of fields that do not have physical asymptotic states. We envisaged this mechanism in an asymmetric vacuum phase of a complex gauge field theory. More recently, we showed how to define a BRST operator to the broken phase of a generic spontaneous broken field theory. Our intention here is to apply these late concepts to the previous complex field theory in order to give a cohomological characterization of those condensed states as actual physical observables of this theory in its broken phase.

Thin and thick bubble walls. Part I. Vacuum phase transitions

This is the first in a series of papers where we study the dynamicsof a bubble wall beyond usual approximations, such as the assumptionsof spherical bubbles and infinitely thin walls. In this paper, weconsider a vacuum phase transition. Thus, we describe a bubble asa configuration of a scalar field whose equation of motion depends onlyon the effective potential.The thin-wall approximation allows obtaining bothan effective equation of motion for the wall position anda simplified equation for the field profile inside the wall.Several different assumptions are involved in this approximation.We discuss the conditions for the validity of each of them.In particular, the minima of the effective potential musthave approximately the same energy, and we discuss the correct implementation of this approximation.We consider different improvements to the basic thin-wall approximation,such as an iterative method for finding the wall profileand a perturbative calculation in powers of the wall width.We calculate the leading-order corrections.Besides, we derive an equation of motion for the wall without any assumptions about its shape.We present a suitable method to describe arbitrarily deformed walls from the spherical shape.We consider concrete examples and compare our approximations with numericalsolutions. In subsequent papers, we shall consider higher-order finite-width corrections,and we shall take into account the presence of the fluid.

Magnesium oxide nanotube as novel strategies to enhance the anticancer activity of 5-Fluorouracil

We evaluated the adsorption process and anti-cancer activity of functionalized magnesium oxide nanotube (MgONT) adsorbed with 5-Fluorouracil (5-FU) in vacuum and solution (water and toluene) phases via density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. 5-FU is chemisorbed preferentially by oxygen and hydrogen atoms to Mg and O atoms at the end tube (state III) with adsorption energies of approximately −2.01 eV (vacuum), −1.72 eV (water), and −1.84 eV (toluene) by the Perdew-Burke-Ernzerhof (PBE) functional and 6-311+G** standard basis set. TDDFT methods illustrated that the maximum optical absorption by the CAM-B3LYP method is in the UV region with an energy of 4.57 eV and a maximum absorption at 271.36 nm. Analysis of molecular docking illustrated that the interaction of 5-FU, as antineoplastic agent, with Mg and O atoms of the nanotube via its O- and H-atoms can enhanced inhibitory effects against Human Epidermal growth factor Receptor 2 (HER2) and Epidermal growth factor receptor (EGFR). The results illustrated that 5-FU/MgO complex could be useful for the development of novel anti-cancer agents to treat breast cancer patients.

Cost Estimates of Roll-to-Roll Production of Organic Light Emitting Devices for Lighting

White organic light emitting devices (WOLEDs) offer distinct advantages as solid state lighting sources, including high energy efficiency, superior color quality, and a flexible, thin profile that can accommodate a vast array of possible fixture designs. Recent advances in device lifetime and high speed deposition suggest that mass production of WOLED panels is approaching an inflection point. To understand the tradeoffs in the volume manufacturing of WOLED lighting panels, in this work, we estimate the cost of white WOLED panel production based on vacuum and vapor phase deposition in a roll-to-roll production line envisioned to yield an annual capacity of at least 6 × 106 m2. Assuming a WOLED operating luminance at 10 klm/m2, we anticipate a $12.5/klm cost of a WOLED light engine that includes the cost of the current driver and packaging. With incremental reduction in material and driver costs and improved luminance, the cost of WOLED lighting can be reduced to $6.3/klm in the near term, potentially positioning WOLEDs for use in numerous premium lighting applications.

Computational insights into E/Z isomerism of fluoxastrobin, an antifungal agent: A DFT/TD-DFT study

Herein, inspired by the success of strobilurins in fungicidal activity bioassays, DFT (Density Functional Theory)-based quantum chemical computations were performed on fluoxastrobin, a fluorinated strobilurin fungicide. Its formulation has E/Z isomerism around the C=N bond. It is highly advantageous to utilize quantum chemical methods to acquire more insights into E/Z isomerism and to gain supplemental confirmations in terms of experimental results. In this respect, the geometries of the E and Z isomers of fluoxastrobin were optimized both in the vacuum and in 1-octanol, acetonitrile, DMSO, and water phases using the DFT/B3LYP/6-311++G (d, p) methodology. Both experimental and theoretical FTIR and UV-vis evaluations were performed for the isomers. TD-DFT/B3LYP/6-311++G (d, p) theory level computations were determined that the observed peaks were mostly caused from the π→π∗ and n→π∗ transitions. Also, quantum chemical reactivity descriptors and physicochemical parameters were calculated for both vacuum and solvent phases. Accordingly, computations in all studied phases estimate the E isomer to be preferred with energy values in the range of 2.51-3.77 kcal/mol. Natural bond orbital (NBO) analysis was also carried out to determine the intermolecular interactions and their corresponding stabilization energies. Last, with the help of Gibbs solvation free energy values, 1-octanol/water partition coefficients were calculated and lipophilicity evaluations of both isomers were performed.