The application of lithium-sulfur (Li-S) batteries as efficient energy storage systems is hindered by the polysulfide shuttle and expansion effects. To overcome these obstacles, we employed density functional theory (DFT) to explore the 1T-NbS monolayer as a cathode material for Li-S batteries, particularly focusing on the effects of uniaxial tensile strain. Our results indicate that the pristine 1T-NbS monolayer presents a balanced adsorption affinity for LiPSs, thereby mitigating the shuttle effect. The bond formation information is investigated through comprehensive analysis of charge transfer, physical/chemical adsorption, and projected crystal orbital Hamiltonian population (pCOHP). The projected density of states (PDOS) analysis reveals the role of sulfur atoms near the Fermi surface in the lithiation process. Notably, the system keeps superior metallic characteristics, alongside a diminished decomposition energy barrier (0.45 eV), lowered lithium-ion migration energy barrier (0.16 eV), and a diminished positive Gibbs free energy change (0.41 eV) during the sulfur reduction reaction (SSR). The imposition of uniaxial tensile strain on the 1T-NbS monolayer improves its adsorptive capacity for LiPSs and bolsters the retention of lithium-sulfur aggregates. These insights underscore the role of tensile strain in amplifying the efficiency of two-dimensional transition metal dichalcogenides as cathode materials of Li-S batteries.

Energy flow in biomolecules is a dynamic process vital for understanding health, disease, and applications in biotechnology and medicine. In crowded environments, where biomolecular functions are modulated, comprehending energy flow becomes crucial for accurately understanding cellular processes like signaling and subsequent functions. This study employs ultrafast transient absorption spectroscopy to demonstrate energy funneling from the photoexcited heme of bovine heart cytochrome to the protein exterior, in the presence of common synthetic (Dextran 40, Ficoll 70, PEG 8 and Dextran 70) and protein-based (BSA and β-LG) crowders. The through-space energy transfer mode for ferric and the methionine rebinding mode for ferrous cytochrome show the strongest solvent coupling. The heterogeneous behaviour of crowders, influenced by crowder-protein interactions and caging effects at certain higher concentrations, reveal diverse trends. Notably, protein crowders perturb all transport routes of vibrational energy transfer, causing delays in energy transfer processes. These findings provide significant insights into the basic tenets of energy flow, one of the most fundamental processes, in crowded cellular environments.

Scientists are interested in the CO cycle in the atmosphere of Venus. In order to study the cycle involving the reaction with chlorine, it is necessary to investigate the reaction intermediate, the ClCO radical, which can be used to prove the hypothesis of the CO cycle on Venus. In the present work, we observed the pure rotational transitions of the ClCO radical by FTMW spectroscopy. Due to the large rotational constant , only = 0 a-type transitions were observed. Based on the experimental results of the ClCO radical, it was found that the unpaired electron is mainly located in the in-plane p orbital of the central carbon atom. The distribution of the unpaired electron on the chlorine nucleus does not extend toward the direction of the Cl-C bond, which is different from the case of the FCO radical.

Organic carbonates and their mixtures are frequently used in electrolyte solutions in lithium-ion batteries. Rationalization and tuning of the related Li solvation processes are rooted in the proper identification of the representative low-energy spatial structures of the microsolvated Li(S) clusters. In this study, we introduce an automatically generated database of conformational energies (CEs), LICARBCONF806, comprising 806 diverse conformers of Li clusters with 7 common organic carbonates. A number of standard and composite density functional theory (DFT) approaches and fast semi-empirical methods are examined to reproduce the reference CEs obtained at the RI-SCS-MP2/CBS level of theory. A hybrid PBE0-D4 functional paired with the def2-QZVP basis set is the most robust in reproducing the reference values while composite B97-3c demonstrates the best cost-benefit ratio. Contemporary tight-binding semi-empirical methods GFNn-xTB can be used for the filtering of high-energy structures, but their performance worsens significantly when the limited number of low-energy (CE < 3 kcal mol) conformers are to be sorted. Thermal corrections used to convert electronic energies to respective Gibbs free energies and especially corrections imposed by a continuum solvation model can significantly influence both the conformer ranking and the width of the CE distribution. These should be appropriately taken into account to identify lowest energy conformers in solution and at non-zero temperatures. The almost black-box conformation generation workflow used in this work successfully predicts representitative low-energy four-coordinated conformers of Li clusters with cyclic carbonates and unravels the complex conformational nature of the clusters with flexible linear carbonates.

Kaede is the prototype of the optical highlighter proteins, which are an important subclass of the fluorescent proteins that can be permanently switched from green to red emitting forms by UV irradiation. This transformation has important applications in bioimaging. Optimising brightness, enhancing fluorescence characteristics, in these proteins is an important objective. At room temperature, the excited state dynamics of the red form of the kaede chromophore are dominated by a broad distribution of conformers with distinct excited state kinetics. Here, we investigate substituent effects on the photophysics of this form of the kaede chromophore. While an electron withdrawing substituent (nitro) red shifts the electronic spectra, the modified chromophores showed no significant solvatochromism. The lack of solvatochromism suggests small changes in permanent dipole moment between ground and excited electronic states, which is consistent with quantum chemical calculations. Ultrafast fluorescence and transient absorption spectroscopy reveal correlations between radiative and nonradiative decay rates of different conformers in the chromophores. The most significant effect of the substituents is to modify the distribution of conformers. The results are discussed in the context of enhancing brightness of optical highlighter proteins.

The development of chiral compounds exhibiting circularly polarized luminescence (CPL) has advanced remarkably in recent years. Designing CPL-active compounds requires an understanding of the electric transition dipole moment () and the magnetic transition dipole moment () in the excited state. However, while the direction and magnitude of can, to some extent, be visually inferred from chemical structures, remains elusive, posing challenges for direct predictions based on structural information. This study utilized binaphthol, a prominent chiral scaffold, and achieved CPL-sign inversion by strategically varying the substitution positions of phenylethynyl (PE) groups on the binaphthyl backbone, while maintaining consistent axial chirality. Theoretical investigation revealed that the substitution position of PE groups significantly affects the orientation of in the excited state, leading to CPL-sign inversion. Furthermore, we propose that this CPL-sign inversion results from a reversal in the rotation of instantaneous current flow during the S → S transition, which in turn alters the orientation of . The current flow can be predicted from the chemical structure, allowing anticipation of the properties of and, consequently, the characteristics of CPL. This insight provides a new perspective in designing CPL-active compounds, particularly for -symmetric molecules where the S → S transition predominantly involves LUMO → HOMO transitions. If represents the directionality of electron movement during transitions, , the "difference" in electron locations before and after transitions, then could be represented as the "path" of electron movement based on the current flow during the transition.

The design of type-II van der Waals (vdW) heterostructures is regarded as a promising route to produce green hydrogen photocatalytic water splitting. To this aim, we propose novel vertically stacked vdW heterostructures based on ZnO and Janus VXY (X = Br, Cl, Y = Se, and Te) phases, and investigate their optoelectronic properties and photocatalytic performance by means of density functional theory simulations. The thermal stability of the heterostructures is confirmed by molecular dynamics simulations at 300 K. The HSE06 calculated band structures show that a specific stacking of ZnO-VBrSe and ZnO-VClSe exhibits an indirect band gap with type-II band alignment, while all other stackings exhibit a direct band gap with type-I band alignment. The type-II band alignment, along with the difference in the work function and the electrostatic potential between the ZnO and VXY monolayer, will result in a built-in electric field direct from the ZnO monolayer to the VXY monolayer which is crucial for photogenerated charge separation, and prevents the charge recombinations. The optical absorption coefficient of all the considered ZnO-VXY heterostructures displays the first excitonic peak in the energy range required for photocatalysis applications. Based on the band edge potential analysis, all the studied systems are capable of starting an oxygen evolution reaction spontaneously, while some external stimuli will be required to initiate the hydrogen evolution reaction. The reported results suggest that the proposed ZnO-VXY vdW heterostructures have great potential for photocatalysis and optoelectronic device applications.

In the field of finding ground and excited states, where quantum computation holds significant promise, using a variational quantum eigensolver (VQE) is a typical approach. However, the success of this approach is vulnerable to two factors: classical optimization for the ansätz parameters and noise from quantum devices. To address these challenges, we adopted particle swarm optimization (PSO) based on swarm intelligence for VQE and presented its performance. Furthermore, a modified PSO, gradient-based adaptive quantum-behaved particle swarm optimization (GAQPSO), is proposed. This algorithm adaptively upgrades parameters based on gradients or shared information within the swarm, enhancing optimization capability and noise resistance. We tested this algorithm using VQE simulations on several molecular systems with different geometries and found that, when using random initial values, GAQPSO achieves accurate results even in the presence of noise, whereas traditional PSO, QPSO, COBYLA, and gradient-based algorithms (GD and L-BFGS-B) fail. The GAQPSO algorithm presents a novel approach to optimizing VQE, demonstrating superior performance in parameter optimization and noise resilience compared to traditional optimization algorithms. This effectively advances the process of achieving a quantum advantage for quantum computing in quantum chemistry problems.

Understanding the mechanisms of material transport in protocells before the emergence of proteins is crucial to uncovering the origins of cellular life. While previous research has demonstrated that direct permeation is a feasible transport mechanism for protocells with fatty acid-based membranes, this process becomes less efficient as membranes evolve to include phospholipids-before the advent of protein transport systems. To address this knowledge gap, we investigated fundamental processes that could have facilitated molecular transport in such protein-free systems. In this study, we identify and characterize nanoscopic transient pores spontaneously forming in phospholipid vesicle membranes, likely driven by osmotic imbalances. We for the first time pinpointed individual pore formation events by observing intermittent fluorescence bursts resulting from the brief influx of fluorescent tracers into the vesicular interior. Kinetic analysis of these burst profiles reveals that these membrane pores possess lifespans of about fourteen milliseconds and radii of around twenty nanometers, suggesting that they are sufficiently large and long-lived to enable the transport of essential nutrients and metabolic products. These findings are confirmed by conventional pore-sizing methods using tracers of various sizes and supported by numerical simulations. Importantly, this transient pore formation does not compromise the integrity of the membrane, nor does it require the participation of proteins or peptides. Our results indicate that spontaneous transient poration provides a viable mechanism for molecular transport through the membrane of primitive cellular entities, offering an alternative to simple diffusion or direct permeation. This study sheds light on potential evolutionary strategies employed by pre-protein protocellular entities to facilitate material transport, contributing to our understanding of the early mechanisms that may have driven the origin of life.

Nonadiabatic molecular dynamics simulations were performed to explore the photoisomerization pathway from isoxazole (iso-OXA) to oxazole (OXA), considering four electronic states. The XMS-CASPT2 and SA4-CASSCF theories were employed to describe these electronic structures, which were caused by 12 electrons in 11 orbitals with the cc-pVDZ + sp diffuse basis set; the Gaussian s- and p-type diffuse functions were extracted from Dunning's aug-cc-pVDZ function. The potential energy and its gradient at each time step were computed on-the-fly at these levels in the time evolution of the classical trajectory. When the two electronic states were close to each other, the trajectory surface hopping (TSH) judgment between the two adjacent states was carried out by the anteater procedure based on the Zhu-Nakamura formula (ZN-TSH). The two different excited state lifetimes were found to exist in the first electronic state (S), estimated at 10.77 and 119.81 fs. Upon photoexcitation, the N-O bond breaks and energetically relaxes to the ground state (S). In the pathway leading to the main product, azirine formation, the 5-membered ring retains a planar structure while undergoing a non-adiabatic transition with an increasing N-O bond distance. Furthermore, it was verified that a 1,2-shift takes place in the pathway that results in the production of ketenimine, causing a nonadiabatic transition.

This work presents a systematic investigation of porphyrin sensitizers for application in dye-sensitized solar cells (DSSCs). Density functional theory calculations, including both static and time-dependent methods, were employed to evaluate a series of candidate dyes for their potential to achieve high power conversion efficiency. The well-established SM315 dye, known for its record-breaking PCE of 13%, was adopted as a reference point. A range of metal atoms including alkaline-earth and 3d transition metals were screened, Ca was identified as the most promising metal for light capture and conversion. Ca-porphyrin-based sensitizer was further modified by introducing different axial ligands and four distinct bridging units. The designed dyes exhibit red-shifted absorption spectra and optimal frontier orbital alignment with the semiconductor's conduction band, promoting efficient light capture and charge transfer. In addition to these core parameters, a comprehensive analysis of light harvesting efficiency (LHE), reorganization energy (), short-circuit current density (), exciton binding energy (EBE), open-circuit voltage (), electron transfer rate (), polarization () and hyperpolarization () collectively paint a clear picture of superior light capture, efficient charge transport dynamics, and minimized energy losses within the designed dyes. This ultimately translates to the remarkable power conversion efficiency (PCE) exceeding 27% achieved by the specifically designed dye with the Ca as metal atom, 4,4'-bipyridine as axial ligands and cyclopenta-1,3-diene as bridging unit, surpassing the performance of SM315 dye (13% PCE). This systematic study combines the design of high-performance porphyrin sensitizers through molecular engineering with a comprehensive investigation of their impact on DSSC function using advanced computational methods.

The conversion of the highly selective CO reduction reaction (CORR) into desired value-added multicarbon compounds, like CH, is crucial, but it is mainly constrained by the high energy barrier for C-C coupling and the multi-electron transfer process. Herein, M/TiO and M/TiO-V (M = Cu, Pd, CuPd, and V refers to the surface oxygen vacancy) catalysts were designed to study the CORR towards CH by using density functional theory (DFT). We found that the surface oxygen vacancy enhances the adsorption ability of studied catalysts. The CO molecule is strongly adsorbed at the metal-surface interfaces of Cu/TiO-V, Pd/TiO-V and CuPd/TiO-V catalysts with adsorption energies of -1.79, -1.75 and -1.71 eV, respectively. Furthermore, the C-C coupling reaction does not occur on the Cu and PdCu cluster sites of the M/TiO-V catalysts, indicating the inactivity of these sites for C products. However, Pd/TiO, CuPd/TiO and M/TiO-V interfaces favor the C-C coupling reaction and therefore have the potential to reduce CO to C products. Additionally, the Gibbs free energy calculations reveal that the surface oxygen vacancy improves the OCCO hydrogenation to CH at the CuPd/TiO-V interface.

We present a comprehensive theoretical analysis of the structural and electronic properties of a van der Waals heterostructure composed of CdS and α-Te single layers (SLs). The investigation includes an in-depth study of fundamental structural, electronic, and optical properties with a focus on their implications for photocatalytic applications. The findings reveal that the α-Te SL significantly influences the electronic properties of the heterostructure. Specifically, the optical properties of the heterostructure are notably dominated by the contribution of α-Te. The layer-resolved density of states analyses indicate that the valence and conduction bands near the Fermi level are mainly determined by the α-Te SL. Band edge analyses demonstrate a type-I band alignment in the heterostructure, causing charge carriers (electrons and holes) to localize within α-Te. The electronic properties can be further modulated by external strain and electric fields. Remarkably, the CdS-α-Te heterostructure undergoes a transition from type-I to type-II band alignment when subjected to biaxial strain and an external electric field. This may be interesting for the application of the heterostructure for photocatalysis.

Compared with their linear counterparts, cyclic peptides, characterized by their unique topologies, offer superior stability and enhanced functionality. In this review article, the rational design of cyclic peptide primary structures and their significant influence on self-assembly processes and functional capabilities are comprehensively reviewed. We emphasize how strategically modifying amino acid sequences and ring sizes critically dictate the formation and properties of peptide nanotubes (PNTs) and complex assemblies, such as rotaxanes. Adjusting the number of amino acid residues and side chains allows researchers to tailor the diameter, surface properties, and functions of PNTs precisely. In addition, we discuss the complex host-guest chemistry of cyclic peptides and their ability to form rotaxanes, highlighting their potential in the development of mechanically interlocked structures with novel functionalities. Moreover, the critical role of computational methods for accurately predicting the solution structures of cyclic peptides is also highlighted, as it enables the design of novel peptides with tailored properties for a range of applications. These insights set the stage for groundbreaking advances in nanotechnology, drug delivery, and materials science, driven by the strategic design of cyclic peptide primary structures.

Non-canonical nucleobase pairs differ from canonical Watson-Crick (WC) pairs in their hydrogen bonding patterns. This study uses density functional theory with empirical dispersion correction to examine the stability and electronic properties of free adenine dimers stabilized by hydrogen bonds along the WC, Sugar (S), and Hoogsteen (H) edges. Dispersion correction is crucial for accurate interaction energy evaluation. The most stable adenine dimer is stabilized by N-H⋯N hydrogen bonds in gas and solvent phases. Binding energy decreases by ∼10.2 kcal mol for dimers with both C-H⋯N and N-H⋯N bonds, increasing the donor-acceptor distance. However, with a sugar-phosphate backbone, dimers with C-H⋯N and N-H⋯N bonds have higher binding energy in an implicit solvent, emphasizing the role of C-H⋯N interactions in stability and nucleic acid folding dynamics. This study highlights noncovalent interactions, such as hydrogen bonding and π-π stacking, within adenine pairs with potential applications in biosensing and DNA-based self-assembly on nanomaterial interfaces.

The valence and core electronic structure of three non-steroidal anti-inflammatory drugs (methyl salicylate, fenoprofen and ketoprofen) have been studied by photoelectron and soft X-ray absorption spectroscopy, supported by theoretical calculations of the molecular and electronic structure. The conformational landscape has been explored for sixteen low-energy conformers of fenoprofen and ketoprofen, and the energies of both compounds fall into two groups with steric similarities, separated by about 3 kJ mol. Valence band photoelectron spectra agree with previous results, and the spectra have been calculated using two approaches. We find the outer valence Green's function method gives good results, but the P3+ method is a little better, particularly for outer valence ionic states. Carbon and oxygen 1s photoemission spectra are reported and are in acceptable agreement with the theory. The C and O K near-edge X-ray absorption fine structure spectra are reported and interpreted by comparison with reference compounds. We analyse the data to provide rough estimates of the energies of the unoccupied orbitals in methyl salicylate.

This study provides new theoretical insights into the vibrational spectra of Ln(III) complexes, along the lanthanide series by utilizing the LModeAGen protocol and integrating cutting-edge topological ideas. It provides a quantitative interpretation of the vibrational spectra of [Ln(trensal)] complexes at the B3LYP/MWB(Ln)/6-311++G** ( from 46 (La) to 60 (Lu)) level using the characterization of normal modes from the local vibrational mode theory. This involves decomposing normal vibrational modes related to the complex formation, distortions in the coordination sphere, and C-H vibrations into local mode contributions, offering particularly promising results aimed at the design of highly luminescent lanthanide complexes. This study also delivers key theoretical insights into the chemical bonding of the coordination sphere of [Ln(trensal)] by combining the local vibrational mode theory and the bond overlap model to achieve relationships between bond properties, including those of the Badger-type. Altogether, we present the theoretical framework necessary to quantitatively interpret the vibrational spectra of [Ln(trensal)] complexes along the lanthanide series and gain a better understanding of the lanthanide-ligand chemical bonds, thereby enhancing our understanding of their chemistry and guiding future design efforts.

Radiation induced damage of extractant molecules is a well-known phenomenon responsible for reducing efficiency and increasing the waste and cost of reprocessing used nuclear fuel (UNF). As such, understanding early-stage (pico- to nanoseconds) radiation-induced reaction mechanisms is essential for informing the design of next generation extractants with enhanced radiation robustness. Here we utilized picosecond and nanosecond electron pulse radiolysis experiments to probe the early-stage radioactive environment experienced by the organic phase extractant ,,','-tetraoctyldiglycolamide (TODGA), proposed for separating highly radioactive trivalent minor actinides (specifically americium and curium) from the trivalent lanthanides. Using comparisons to the similar ionization potential (IP) solute -xylene, this work determined the mechanism of reaction with the ionized diluent (, -dodecane radical cation, DD˙) is hole transfer to produce TODGA˙. At high TODGA concentrations (>100 mM), the majority of this transfer occurs faster than 10 ps the capture of DD˙ holes prior to their solvation with a = 300 mM. The surviving solvated holes were captured with = (2.38 ± 0.15) × 10 M s. Attempts at subsequent hole transfer to lower IP solutes found that only 10% of holes were transferred, indicating bond rupture of TODGA˙ occurs within 2.6 ns at 200 mM TODGA. Possible reaction pathways for the rapid decomposition of TODGA˙ were explored using a combination of experiments and density functional theory (DFT) calculations.

The mechanism of a solvent consisting of choline chloride and glycerol (ChCl/GLY) for extracting phenolic compounds from coal tar was theoretically studied using density functional theory calculations and molecular dynamics simulations. The thermodynamic properties, interaction essence, and molecular dynamics properties of the extraction system were investigated, as well as the influence of ChCl/GLY on the vibration spectra of phenolic compounds. The results show that the solvation free energy of phenolic compounds in ChCl/GLY is more negative than that in coal tar, leading to the spontaneous transfer of phenolic compounds from coal tar to ChCl/GLY. The electrostatic and dispersion interactions between phenolic compounds and ChCl/GLY have similar significance in the extraction process, with interaction energies ranging from -46 to -53 kJ mol. The mixing of phenolic compounds with ChCl/GLY has minimal impact on their internal molecular structure, however, it does reduce the diffusion coefficients of each component in ChCl/GLY and shortens the lifetime of hydrogen bonds in both phenolic compounds and ChCl/GLY. The first shell of each phenolic compound is surrounded by 1.15 chloride ions. Following dissolving in ChCl/GLY, the stretching vibration peaks of phenolic compounds, namely the -OH and C-H/-CH regions, undergo a shift. The results enhance comprehension of the extraction process of phenolic compounds by DES.

This work investigates the interaction of silicon with ruthenium, extending from Si-defect centers in ruthenium bulk to the adsorption of Si on the Ru(0001) surface. Using density functional theory (DFT) we calculate the interaction energies of up to 2 monolayers (MLs) of Si with this surface, uncovering the initial formation of ruthenium silicide (RuSi). Our results demonstrate that Si readily forms substitutional defects (Si) in bulk ruthenium. These defects are further stabilized on the Ru(0001) surface, resulting in a distinct propensity for forming Ru-Si mixed layers - which can thus be described by stoichiometry RuSi. Overlayers of surface-adsorbed Si adatoms and RuSi mixed layers are iso-energetic at 0.5 ML, with the latter becoming increasingly energetically favored at higher Si coverages. We further examine the influence of RuSi formation with respect to oxide formation, focusing on coverage-dependent energy differences. Our results show RuSi layers are energetically favored with respect to the forming oxide for silicon and oxygen coverages above 1.1 ML, respectively. In addition, the formation of RuSi and the subsequent oxidation of Ru and RuSi were also investigated experimentally using XPS. This confirmed the DFT prediction, with negligible oxide formation on the RuSi sample, whereas the unprotected Ru surface showed extensive RuO formation under the same conditions. Our study not only enhances the understanding of Ru surface chemistry but also suggests a straightforward computational approach for screening the oxidation resistance of surface coatings.

Based on first-principles calculations, we have predicted a novel group of 2D p-state Dirac half-metal (DHM) materials, YX (Y = Li, Na; X = Se, Te) monolayers. All the monolayers exhibit intrinsic ferromagnetism. Among them, LiTe and NaSe open topologically nontrivial band gaps of 4.0 meV and 5.0 meV considering spin-orbit coupling (SOC), respectively. The Curie temperature of LiTe is 355 K. The non-zero Chern number and the presence of edge states further confirm that the LiTe monolayer is a room-temperature ferromagnetic material and a quantum anomalous Hall (QAH) insulator. Additionally, it is found that YX (Y = Li, Na; X = Se, Te) monolayers exhibit strong robustness against strain and electric fields. Finally, we have proposed the growth of YX (Y = Li, Na; X = Se, Te) monolayers on h-BN substrates, which shows promise for experimental synthesis. Our research indicates that YX (Y = Li, Na; X = Se, Te) monolayers exhibit strong robustness as DHMs, showcasing significant potential for realizing the intrinsic quantum anomalous Hall effect (QAHE).