Dissociation Process Research Articles

Insights into the Dissociation Process and Binding Pattern of the BRCT7/8-PHF8 Complex.

DNA topoisomerase 2-binding protein 1 (Topbp1) plays a crucial role in activating the ataxia-telangiectasia mutated and rad3-related (ATR) complex to initiate DNA damage repair responses. For this process to occur, it is necessary for PHF8 to dissociate from Topbp1. Topbp1 binds to the acidic patch sequence (APS) of PHF8 through its C-terminal BRCT7/8 domain, and disrupting this interaction could be a promising strategy for cancer treatment. To investigate the dissociation process and binding pattern of BRCT7/8-PHF8, we employed enhanced sampling techniques, such as steered molecular dynamics (SMD) simulations and accelerated molecular dynamics (aMD) simulations, along with self-organizing maps (SOM) and time-resolved force distribution analysis (TRFDA) methodologies. Our results demonstrate that the dissociation of PHF8 from BRCT7/8 starts from the N-terminus, leading to the unfolding of the N-terminal helix. Additionally, we identified critical residues that play a pivotal role in this dissociation process. These findings provide valuable insights into the disassociation of PHF8 from BRCT7/8, which could potentially guide the development of novel drugs targeting Topbp1 for cancer therapy.

Calcium Chemistry in Carbon-rich Circumstellar Environments: The Laboratory and Astronomical Discovery of Calcium Dicarbide, CaC2 * * This work is based on observations done using the 100 m Green Bank Telescope (GBT), the Yebes 40 m telescope (projects 19A010, 20A017, 20B014, and 21A019), and the IRAM 30 m telescope. The 100 m GBT is an instrument of the Green Bank

Calcium dicarbide, CaC2, has been characterized at high resolution in the laboratory, and its main isotopologue, 40CaC2, has been assigned to 14 rotational emission lines between 14 and 115 GHz, including 12 previously unassigned lines, in the expanding molecular envelope of the evolved carbon star IRC+10216. Aided by high-level quantum calculations and measurements of multiple isotopologues, CaC2 is determined to be a T-shaped molecule with a highly ionic bond linking the metal atom to the C2 unit, very similar in structure to isovalent magnesium dicarbide (MgC2). The excitation of CaC2 is characterized by a very low rotational temperature of 5.8 ± 0.6 K and a kinetic temperature of 36 ± 16 K, similar to values derived for MgC2. On the assumption that the emission originates from a 30″ shell in IRC+10216, the column density of CaC2 is (5.6 ± 1.7) × 1011 cm−2. CaC2 is only the second Ca-bearing molecule besides CaNC and only the second metal dicarbide besides MgC2 identified in space. Owing to the similarity between the predicted ion–molecule chemistry of Ca and Mg, a comparison of the CaC2 abundance with that of MgC2 and related species permits empirical inferences about the radiative association–dissociative recombination processes postulated to yield metal-bearing molecules in IRC+10216 and similar objects.

»Denn Ich ist ein Anderer«

Rimbaud’s formulation in his Lettre du voyant to Paul Demeny, »Car Je est un autre,« which has become famous in German as »Denn Ich ist ein Anderer« [For I is an Other/For I is someone else] (Rimbaud 1997, 20–21) can, in its formulaic nature, be read as a motto for various practices which effect a dissociation between the addressee and the author of lyric texts. In this text, these dissociation processes are referred to as practices of dereferentialization. The first thesis of this article is that an ambiguization of the addressee reference – not only by means of epitextual authorial poetological statements according to the abovementioned reasoning, but indeed from within the texts themselves – can manifest itself as a strategy in poetry production which leads to a poem becoming ambiguous, that is, allowing for more possible interpretations and as a consequence acquiring a positive quality. That dereferentialization has also proved to be a strategy of literary reception (and more specifically within the practice of interpretation) whose goal is to secure a property that is considered constitutive of poetry forms the second thesis presented here. Both theses are based on the assumption that ambiguity is an axiological value within the social practice of ›lyric poetry‹. The article concludes with a discussion of whether the reception-side dereferentialization is sometimes performed too uncritically, with a view towards Till Lindemann’s Undank und Wenn du schläfst.

Social class and moral judgment: a process dissociation perspective.

Do social classes differ in moral judgment? Previous research showed that upper-class actors have a greater inclination toward utilitarian judgments than lower-class actors and that this relationship is mediated by empathic concern. In this paper, we take a closer look at class-based differences in moral judgment and use the psychometric technique of process dissociation to measure utilitarian and deontological decision inclinations as independent and orthogonal concepts. We find that upper-class actors do indeed have a greater inclination toward decisions consistent with utilitarian principles, albeit only to a quite small extent. Class-related differences are more pronounced with respect to deontological judgments, in so far as upper-class actors are less inclined to judgments consistent with deontological principles than lower-class actors. In addition, it is shown that class-based differences in utilitarian judgments are mediated by cognitive styles and not so much by empathic concern or moral identity. None of these potential mediators explains class-based differences in the inclination toward deontological judgments.

Hydroxyl-assisted globally spontaneous dynamic oxygen migration on biphenylene

Dynamic covalent interfaces (DCIs) can autonomously adjust their internal structures and dynamically respond to changes in the external environment, thus holding broad application prospects in drug delivery, molecular detection, and interface catalysis. However, the dynamic properties of such DCIs greatly rely on the localized exchanges or formations of chemical bonds, seriously constraining the adaptive response efficiency. To transcend the limitations of the dynamic two-dimensional (2D) scales, employing the experimentally synthesized biphenylene monolayer as a prototype, we systematically study the hydroxyl-assisted globally spontaneous dynamic oxygen migration on biphenylene interface based on the first-principles calculations and machine-learning-based molecular dynamics (MLMD) simulations. The calculated results indicate that the stable dangling oxygen atoms on the biphenylene monolayer can attract the proton in the interfacial water, which in turn undergoes a water dissociation process and produces hydroxyl groups on the biphenylene interface. Assisted by the hydroxyl groups, the dangling oxygen atoms can achieve long-range migration, exhibiting notably low energy barriers (0.09 eV, 0.04 eV) due to the reversible proton transfer reactions. Therefore, the local dynamic covalent behaviors of oxygen atoms on the biphenylene interface are broken with the oxygen atoms migrating between the adjacent C4 rings. More importantly, the charge density difference and Bader charge analysis demonstrate that the presence of hydroxyl groups significantly enhance the stability of the dangling oxygen, effectively reducing energy barriers of oxygen migration compared to epoxy on the biphenylene interface. Furthermore, the MLMD trajectories visually show the process of realizing large-area DCIs on the biphenylene monolayer. Our work not only clarifies the oxygen-related dynamic behavior of the biphenylene interface, but also provides new ideas for the realization of large-area dynamic covalent materials (DCMs) on other carbon-based or 2D materials.

Assessment of Production Performance and Uncertainty in the UBGH2-6 Gas Hydrate Reservoir, Ulleung Basin

This study delineates the intricate dynamics of gas hydrate production in the UBGH2-6 reservoir, located in the Ulleung Basin, by deploying a comprehensive simulation model. By integrating a sensitivity analysis with Latin hypercube sampling-based Monte Carlo simulations, we evaluated the influences on gas and water production and explored the underlying uncertainties within this gas hydrate reservoir. The simulation model revealed significant findings, including the production of approximately 440 t of gas and 34,240 t of water, facilitated by a depressurization strategy at 9 MPa for a year. This highlights the pivotal roles of porosity, permeability, and thermal properties in enhancing production rates and influencing hydrate dissociation processes. Sensitivity analysis of 19 parameters provides insights into their impact on production, identifying the key drivers of increased production rates. Furthermore, uncertainty analysis examined 300 reservoir models, utilizing statistical percentiles to quantify uncertainties, projecting a median gas production of approximately 455 t. This study identifies critical factors affecting gas hydrate production and offers valuable insights for future exploration and exploitation strategies, making a significant contribution to the field of gas hydrate research.

Oxygen vacancy-enriched kaolinite/WO3-x nanocomposites exhibiting enhanced photo-synergetic H2O2 activation for tetracycline degradation boosted by hydroxyl groups and exciton

The efficient activation of H2O2 into hydroxyl and superoxide radicals with strong oxidizing power is an often overlooked but challenging issue. In this study, oxygen vacancy-enriched kaolinite/WO3-x composites (KW7) were prepared by a three-step method. Benefiting from abundant oxygen vacancies and surface hydroxyl groups, KW7 composite exhibited excellent photocatalytic H2O2 activation performance. The TC degradation experiments revealed that the KW7/H2O2/hv system exhibited the highest rate constant (k) of approximately 0.1561 min−1, which was 9.4, 5.3, and 5.1-fold greater than those of Kaol/H2O2/hv, WO3/H2O2/hv, and WO3-x/H2O2/hv, respectively. Furthermore, the k value was found to be 5.6 and 4.1 times higher than those observed in the KW7/hv and KW7/H2O2 systems, respectively. The investigation into the underling mechanism of reactive oxygen species generation reveals that, the presence of a high concentration of oxygen vacancies in KW7 results in the increased number of defect energy levels, which leads to the predominance of excitonic effects-mediated O2 activation for the production of 1O2 within the photocatalytic system. On the contrast, in the photo-synergetic H2O2 activation system, due to the strong adsorption of H2O2 on the atoms around Ov, the exciton dissociation process is accelerated and the enhanced charge transfer process is dominant, which effectively activates H2O2 to generate a large amount of •OH and O2•−. The present study provides valuable insights into the photocatalytic activation of H2O2 based on clay composites.

Constructing Interfacial Charge Transfer Channels and Electric Field in Violet Phosphorus-Based van der Waals Heterojunction for Phototherapy of Periodontitis.

Periodontitis, a chronic oral disease instigated by bacteria, severely compromises human oral health. The prevailing clinical treatment for periodontitis involves mechanical scraping in conjunction with antibiotics. Phototherapy is employed to rapidly remove the bacteria and achieve periodontitis treatment, effectively circumventing the adverse effects associated with traditional therapies. Constructing 2D/2D van der Waals (VDW) heterojunctions is a key strategy for obtaining excellent photocatalytic activity. Herein, a 2D/2D violet phosphorus (VP)/Ti3C2 VDW heterojunction is designed using an interfacial engineering strategy. By constructing an electron transport "bridge" (P-Ti bond) at the heterogeneous interface as an effective transfer channel for photogenerated carriers, a compact monolithic structure between the VP and Ti3C2 phases is formed, and the spatial barrier for electron transfer at the interface is eliminated. Meanwhile, the strong directional built-in electric field induced by the intensive electron-coupling effect at the heterogeneous interface served as an internal driving force, which greatly accelerates the exciton dissociation and charge transfer in the photocatalytic process. These excited photogenerated electrons and holes are trapped by O2 and H2O on the surfaces of Ti3C2 and VP, respectively, and are subsequently catalytically converted to antibacterial reactive oxygen species (ROS). The VP/Ti3C2 VDW heterojunction eradicated 97.5% and 98.48% of Staphylococcus aureus and Escherichia coli, respectively, by photocatalytic and photothermal effects under visible light for 10 min. The VP/Ti3C2 nanoperiodontal dressing ointment effectively attenuated inflammatory response, reduced alveolar bone resorption, and promoted periodontal soft and hard tissue repair. Its periodontitis therapeutic effect outperforms the clinically used Periocline.

Methane Hydrate Structure I Dissociation Process and Free Surface Analysis.

Methane hydrates are crystalline solids of water that contain methane molecules trapped inside their molecular cavities. Gas hydrates with methane as a guest molecule form structure I hydrates with two small dodecahedral cages and six tetra decahedral large cages. This study assesses the influence of occupation and the behavior of methane release from the molecular perspective during the dissociation process, particularly for the purpose of testing a series of molecular dynamics simulations. The dissociation cases conducted include an ideal 4 × 4 × 4 and 2 × 2 × 2 supercell methane hydrate system while inducing dissociation with two different types of temperature-rising functions for understanding the limitation and capability. These temperature-rising functions are temperature ramping and a single temperature step simulating in 5-7 various conditions. Temperature step results showed the earliest dissociation starting 50 ps into the simulation at an ΔT of 100 K, while at an ΔT of 80 K, dissociation was not observed. There was not a distinct dissociation preference observed between large and small cages, so it appears that the dissociation affects the entire structure uniformly when temperature increases are applied throughout the system rather than transport from a boundary. Temperature ramping simulations showed that the dissociation temperature increased with a higher heating rate. The mean-squared displacement results for the oxygen atoms in the water molecules at a high heating rate of 400 TK/s showed behavior similar to that for methane gas. As in the temperature step simulation, there were no clear differences in dissociation between large and small cages, which suggested homogeneous dissociation in all cases. Finally, a coordination analysis was performed on a 3 × 4 × 4 structure I methane hydrate with two free surfaces to demonstrate clear free surface boundaries and its location.

One Precursor, Two Different Outcomes: SnO-Graphite Composite and Anion-Doped SnO2 with Ester Surface Functionality.

The technological importance of SnO2 and SnO has invited scientists to explore various aspects, including their synthesis in the nanosize regime, surface functionalization, and composite formation. In the present work, a binuclear Sn2-EDTA complex has been demonstrated to produce a SnO-graphite composite and C, N-codoped SnO2 nanocrystals with ester functionality in quantitative yields by thermal and solvothermal dissociation processes. The products were characterized extensively. While SnO in the SnO-graphite composite exhibited tetragonal symmetry, graphitic carbon had defects. The composite had 12 wt % of graphitic carbon. The role of the SnO-graphite composite as an anode in lithium-ion batteries (LIB) has been evaluated. Solvothermal dissociation of the Sn2-EDTA complex in a propylene glycol medium yielded nanocrystalline SnO2 with yellow color. Agglomerated crystallites had ester functionality on their surfaces. The surface functionality was thermally stable up to 200 °C, and its complete removal yielded tetragonal white-colored SnO2. Co-doping of carbon and nitrogen in yellow SnO2 reduced its optical band gap (2.9 eV). Despite the negative surface charge of the functionalized SnO2, its affinity to rapidly adsorb anionic azo dyes (Congo red and Eriochrome black T) from aqueous solutions has been validated. Following pseudo-second-order kinetics, adsorption data analysis revealed chemisorption as the primary driving force in this process.

Rational Design of Dynamic Interface Water Evolution on Turing Electrocatalyst toward the Industrial Hydrogen Production.

Manipulating the structural and kinetic dissociation processes of water at the catalyst-electrolyte interface is vital for alkaline hydrogen evolution reactions (HER) at industrial current density. This is seldom actualized due to the intricacies of the electrochemical reaction interface. Herein, this work introduces a rapid, nonequilibrium cooling technique for synthesizing ternary Turing catalysts with short-range ordered structures (denoted as FeNiRu/C). These advanced structures empower the FeNiRu/C to exhibit excellent HER performance in 1 m KOH with an ultralow overpotential of 6.5 and 166.2 mV at 10 and 1000 mA cm-2, respectively, and a specific activity 7.3 times higher than that of Pt/C. Comprehensive mechanistic analyses reveal that abundant atomic species form asymmetric atomic electric fields on the catalyst surface inducing a directed evolution and the dissociation process of interfacial H2O molecules. In addition, the locally topologized structure effectively mitigates the high hydrogen coverage of the active site induced by the high current density. The establishment of the relationship between free water population and HER activity provides a new paradigm for the design of industrially relevant high performance alkaline HER catalysts.

Dissociable Neural Mechanisms for Human Inference Processing Predicted by Static and Contextual Language Models.

Language models (LMs) continue to reveal non-trivial relations to human language performance and the underlying neurophysiology. Recent research has characterized how word embeddings from an LM can be used to generate integrated discourse representations in order to perform inference on events. The current research investigates how such event knowledge may be coded in distinct manners in different classes of LMs and how this maps onto different forms of human inference processing. To do so, we investigate inference on events using two well-documented human experimental protocols from Metusalem et al. (2012) and McKoon and Ratcliff (1986), compared with two protocols for simpler semantic processing. Interestingly, this reveals a dissociation in the relation between local semantics versus event-inference depending on the LM. In a series of experiments, we observed that for the static LMs (word2vec/GloVe), there was a clear dissociation in the relation between semantics and inference for the two inference tasks. In contrast, for the contextual LMs (BERT/RoBERTa), we observed a correlation between semantic and inference processing for both inference tasks. The experimental results suggest that inference as measured by Metusalem and McKoon rely on dissociable processes. While the static models are able to perform Metusalem inference, only the contextual models succeed in McKoon inference. Interestingly, these dissociable processes may be linked to well-characterized automatic versus strategic inference processes in the psychological literature. This allows us to make predictions about dissociable neurophysiological markers that should be found during human inference processing with these tasks.

Revealing the Interaction Mechanism between Mycobacterium tuberculosis GyrB and Novobiocin, SPR719 through Binding Thermodynamics and Dissociation Kinetics Analysis.

With the rapid emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb), various levels of resistance against existing anti-tuberculosis (TB) drugs have developed. Consequently, the identification of new anti-TB targets and drugs is critically urgent. DNA gyrase subunit B (GyrB) has been identified as a potential anti-TB target, with novobiocin and SPR719 proposed as inhibitors targeting GyrB. Therefore, elucidating the molecular interactions between GyrB and its inhibitors is crucial for the discovery and design of efficient GyrB inhibitors for combating multidrug-resistant TB. In this study, we revealed the detailed binding mechanisms and dissociation processes of the representative inhibitors, novobiocin and SPR719, with GyrB using classical molecular dynamics (MD) simulations, tau-random acceleration molecular dynamics (τ-RAMD) simulations, and steered molecular dynamics (SMD) simulations. Our simulation results demonstrate that both electrostatic and van der Waals interactions contribute favorably to the inhibitors' binding to GyrB, with Asn52, Asp79, Arg82, Lys108, Tyr114, and Arg141 being key residues for the inhibitors' attachment to GyrB. The τ-RAMD simulations indicate that the inhibitors primarily dissociate from the ATP channel. The SMD simulation results reveal that both inhibitors follow a similar dissociation mechanism, requiring the overcoming of hydrophobic interactions and hydrogen bonding interactions formed with the ATP active site. The binding and dissociation mechanisms of GyrB with inhibitors novobiocin and SPR719 obtained in our work will provide new insights for the development of promising GyrB inhibitors.

Complex formation of ML324, the histone demethylase inhibitor, with essential metal ions: Relationship between solution chemistry and anticancer activity

N-(3-(dimethylamino)propyl-4-(8-hydroxyquinolin-6-yl)benzamide (ML324, HL) is a potent inhibitor of the iron-containing histone demethylase KDM4, a recognized potential target of cancer therapeutics. Herein, we report the proton dissociation and complex formation processes of ML324 with essential metal ions such as Fe(II), Fe(III), Cu(II) and Zn(II) using UV–visible, fluorescence, electron paramagnetic resonance and 1H NMR spectroscopic methods. The electrochemical behaviour of the copper and iron complexes was characterized by cyclic voltammetry and spectroelectrochemistry. The solid phase structure of ML324 analysed by X-ray crystallography is also provided. Based on the solution equilibrium data, ML324 is present in solution in H2L+ form with a protonated dimethylammonium moiety at pH 7.4, and this (N,O) donor bearing ligand forms mono and bis complexes with all the studied metal ions and the tris-ligand species is also observed with Fe(III). At pH 7.4 the metal binding ability of ML324 follows the order: Fe(II) < Zn(II) < Cu(II) < Fe(III). Complexation with iron resulted in a negative redox potential (E'1/2 = −145 mV vs. NHE), further suggesting that the ligand has a preference for Fe(III) over Fe(II). ML324 was tested for its anticancer activity in chemosensitive and resistant human cancer cells overexpressing the efflux pump P-glycoprotein. ML324 exerted similar activity in all tested cells (IC50 = 1.9–3.6 μM). Co-incubation and complexation of the compound with Cu(II) and Zn(II) had no impact on the cytotoxicity of ML324, whereas Fe(III) decreased the toxicity in a concentration-dependent manner, and this effect was more pronounced in the multidrug resistant cells.

Photocatalytic adsorption/degradation of tetracycline by S-scheme BiOI/BiOIO3 p-n heterojunction from dissociation of BiOIO3in-situ solvothermal process

The pollution of tetracycline (TC) had attracted more and more attention due to its unprecedented use and potential hazards. The S-scheme BiOI/BiOIO3 p-n heterojunction was successfully fabricated by in-situ solvothermal treatment of BiOIO3, and was used for the removal of TC from aqueous solutions. The results demonstrated that the construction of S-scheme p-n heterojunction could significantly improve the removal of TC by photocatalytic adsorption/degradation synergism. The removal rate of TC was significantly enhanced after solvothermal modification. The three main reasons for the enhanced removal efficiency were as follows: first, the light absorption range of the BiOIO3 was enhanced by solvothermal treatment; secondly, the construction of the heterojunction was beneficial to the valid separation and migration of the photo-generated carriers; finally, the adsorption of TC enhanced the speed of TC reaching the semiconductor interface and reacting with active species. Trapping tests were conducted to reveal that •O2− and 1O2 are the main reactive species for TC degradation. The nine degradation products were identified by the high performance liquid chromatography-mass spectrometry (HPLC-MS), and the three reaction pathways were deduced. A possible S-scheme p-n heterojunction photocatalytic mechanism was presented on the basis of band structures and active species capturing experiment.

Abstract 4258: An innovative PDX and patient-derived 3D platform for improved translatability of new medical entities

Abstract The preclinical platform landscape in oncology has radically changed in the last 15 years, mainly due to an increased ability to generate patient-derived models. Multiple 3D tumor cell cultures methods, either from established cell lines or from primary cultures, have been developed to assess the activity of therapeutic agents in vitro. These methods are strongly influenced by the experimental conditions, such as cell culture conditions, the presence of 3D supports like Matrigel, and the experimental design of the assay, such as the choice of the dose and the duration of the assay. The ability of these methods to predict drug efficacy in the patient relies not only in the optimization of the experimental settings, but also on the representativeness of the patient population, and on the prevention of model drifts due to clonal selection and/or tumor cell adaptation to culture conditions with passages. In this project, we aimed to develop an innovative 3D cell model platform that addresses all these experimental challenges. To do so, we took advantage of our low passage Tumorgraft platform, a bank of more than 1500 patient-derived xenografts (PDXs) well characterized at molecular and pharmacological level and highly representative of the patient population, to generate the Tumorgraft3D platform. We derived TumorGraft3D models from low passage PDXs, by using proprietary, indication-specific culture conditions. By keeping these models at low passage, we were able to avoid clonal drifts. Moreover, the use of indication specific media allowed the preservation of patient’s and PDX’s tumor histology, molecular traits at genetic, gene expression and proteomic level, and displayed proliferation rates that recapitulate those observed in the parental PDXs. So far, we have successfully developed over 100 models from breast, ovarian, prostate, NSCLC, colorectal and gastric indications, with success rates up to 90%. Ex-vivo testing of standard of care highlighted different response profiles in accordance with the molecular feature of these models. The tumor dissociation process and culture conditions optimized with PDXs were also used for the development of 3D cultures derived from patients’ samples. These data demonstrated that our 3D platform can integrate the complementarity of our PDX and patient-derived 3D platform, which lies in the possibility of evaluating test agent activity in the repeatable and reproducible setting provided by the patient-derived 3D models, as well as in models directly derived from patients with more heterogeneous and indication-specific establishment success rate, and throughput dependent on the amount of primary tumor material. Citation Format: Samaneh Kamali, Stefano Cairo, Fu-Ju Chou, Taylor Light, Mara Gilardi, Brandon Walling, Christine Baer, Hsiu-Wen Tsai, Abhay Andar, Karin Abarca-Heidemann, Maria Mancini. An innovative PDX and patient-derived 3D platform for improved translatability of new medical entities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4258.

Observation of Renner-Teller and predissociation coupled vibronic intensity borrowing in dissociative electron attachment to OCS.

We use a time-of-flight-based velocity map imaging method to look into the dissociative electron attachment to a linear OCS molecule at electron beam energies ranging from 4.5 to 8.5eV. The conical time-gated wedge slice imaging method is utilized to extract fragments' slice images, kinetic energy (KE), and angular distributions, which provide a complete kinematic understanding of this experiment on the dissociative electron attachment process. We observe that the formation of S- is relatively higher than the O- product. Three distinct dissociative KE bands of S-/OCS have been observed for the 5.0 and 6.5eV resonance positions. We notice a prominent rovibrationally coupled bimodality for each KE band in the variation of the most probable KE values. When the electron energy is changed from 5.5 to 6.0eV, we observed vibronic intensity borrowing in the highest momentum band of S- via the Σ → Π symmetric dipole-forbidden transitions within the 1.5eV energy gap. Multiple peaks in the angular distributions of S- and their modeling indicate the presence of Renner-Teller vibronic splitting. Using Q-Chem's implemented complex absorbing potential-equation of motion-electron affinity coupled cluster singles and doubles aug-cc-pVDZ+4s3p level of multireference-based electronic structure theory, we confirm the presence of OCS temporary negative ion bending vibrations and Renner-Teller vibronic splittings for the Π symmetric states. Additionally, we notice the presence of a non-radiative predissociation continuum (bringing down the rotational spectrum) and speed-dependent angular anisotropy in the S- fragmentation. Our findings at the resonance of OCS at 6.5eV closely align with the prediction of vibronic intensity borrowing by Orlandi and Siebrand [J. Chem. Phys. 58, 4513 (1973)].

Metal-organic framework-derived nitrogen-coordinated cobalt single-atom catalysts for triiodide reduction reaction in solar cells

The counter electrode (CE) is a critical component of a dye-sensitized solar cell (DSSC), and developing Pt-free CEs with high catalytic activities and superior stabilities is urgent. Herein, N-doped carbon-supported Cobalt (Co-NC) single-atom catalysts (SACs) were prepared via in-situ pyrolysis. The DSSCs assembled using the Co-NC SACs CEs exhibited superior power conversion efficiencies (9.25%) compared with those of the DSSCs with the N-doped carbon substrate (6.32%), related Cobalt nanoparticles (7.01%), and Pt (8.05%) CEs. This was attributed to the synergistic effects of the N-doped C matrix and single dispersed Co species, which could provide high active Co–Nx as well as a porous structure that offered unobstructed access to the electroactive sites. The catalytic mechanism was elucidated from I3- and I adsorption, I2 and I- dissociation and charge transfer process by DFT calculations. This study expands the range of non-noble metal CE materials for the commercialization of DSSCs.

Dissociation of Hydrofluorocarbon Molecules after Electron Impact in Plasma.

The process of dissociation for two hydrofluorocarbon molecules in low triplet states excited by electron impact in plasma is investigated by ab initio molecular dynamics (AIMD). The interest in the dissociation of hydrofluorocarbons in plasma is motivated by their role in plasma etching in microelectronic technologies. Dissociation of triplet states is very fast, and the reaction products can be predicted. In this work, it was found that higher triplet states relax into the lowest triplet state within a few femtoseconds due to nonadiabatic dynamics, such that the simplest ab initio MD on the lowest triplet state seems to give a reasonable estimate of the reaction channels branching ratios. We provide evidence of the existence of simple rules for the dissociation of hydrofluorocarbon molecules in triplet states. For molecules with a double bond, the bonds adjacent to the double bond dissociate faster than the other bonds.

Dynamics of electron-hole pairs in interface exciplex OLEDs investigated by magnetic field effects

Interface exciplex organic light-emitting diodes (OLEDs) have attracted intense attention due to the advantages including well-confined recombination regions, barrier-free charge transport and thermally activated delayed fluorescence (TADF) characteristics. To investigate the spin evolutions and dynamics of electron-hole (e-h) pairs, such as polaron pairs (PPs) and charge transfer (CT) excitons, in interface exciplex OLEDs is crucial for a better understanding on their energy gain and loss mechanisms. In this work, microscopic dynamics of e-h pairs in interface exciplex OLEDs were investigated by magneto-electroluminescence (MEL) and magneto-conductivity (MC) responses. The interface exciplex OLEDs were fabricated using 4,4,4-tris(N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) as the donor and 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine (T2T) as the acceptor. Hyperfine interaction (HFI)- and different g-factors between electrons and holes (Δg mechanism)-dominated spin flip processes, and recombination and dissociation processes such as triplet-triplet annihilation (TTA) and triplet-charge annihilation (TQA) were identified, and their changes with temperature and current were explored. Our results may provide valuable insights into the evolution of carriers and facilitate the development of interface exciplex-based OLEDs.