Reproducibility of fixed-node diffusion Monte Carlo across diverse community codes: The case of water-methane dimer.

Fixed-node diffusion quantum Monte Carlo (FN-DMC) is a widely trusted many-body method for solving the Schrödinger equation, known for its reliable predictions of material and molecular properties. Furthermore, its excellent scalability with system complexity and near-perfect utilization of computational power make FN-DMC ideally positioned to leverage new advances in computing to address increasingly complex scientific problems. Even though the method is widely used as a computational gold standard, reproducibility across the numerous FN-DMC code implementations has yet to be demonstrated.

Revealing the Neglected Role of Passivation Layers of Current Collectors for Solid-State Anode-Free Batteries.

Anode-free sulfide-based all-solid-state lithium metal batteries (ASSLMBs), which eliminate the need for a lithium metal anode during fabrication, offer superior energy density, enhanced safety, and simplified manufacturing. Their performance is largely influenced by the interfacial properties of the current collectors. Although previous studies have investigated the degradation of sulfide electrolytes on commonly used copper (Cu) and stainless steel (SS) current collectors, the impact of spontaneously formed surface oxides, such as copper oxide (CuO/CuO) and chromium oxide (CrO), on interfacial stability remains underexplored.

Optical detection of single sub-15 nm objects using elastic scattering strong coupling.

Metallic nano-objects play crucial roles in diverse fields, including biomedical imaging, nanomedicine, spectroscopy, and photocatalysis. Nano-objects smaller than 15  nm exhibit extremely low scattering cross-sections, posing a significant challenge for optical detection. An approach to enhance optical detection is to exploit nonlinearity of strong coupling regime, especially for elastic scattering, which is universal to all objects.

Electrocatalytic CO reduction with an immobilized iron complex on gas diffusion electrodes.

The immobilization of molecular electrocatalysts on gas diffusion electrodes (GDEs) overcomes mass transport limitations inherent to solution-phase CO reduction. We report the immobilization of the molecular FeTDHPP catalyst on a GDE supramolecular π-π interactions, achieving a 50-fold catalytic activity increase compared to solution-phase performance.

Laboratory-based in situ and operando tricolor x-ray photoelectron spectroscopy.

Innovative approaches to study buried interfaces and heterogeneous interactions under reaction conditions are crucial for advancing energy and catalytic materials. Our near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) setup is equipped with a tricolor x-ray source, with Al Kα, Ag Lα, and Cr Kα excitation energies, enabling information depth-selective operando and in situ analysis of solid-liquid, solid-gas, and solid-solid interfaces. We present three case studies to demonstrate the systems' capabilities.

Molecular Engineering of Interlayer Exciton Delocalization in 2D Perovskites.

In recent years, significant progress has been made in improving the stability, photocurrent efficiency and charge transport properties of 2D hybrid perovskites, making them increasingly relevant for optoelectronic devices. Although these layered systems are typically considered quantum wells due to carrier confinement, an emerging strategy is to generate new perovskite functionalities with π-conjugated electroactive cores as spacer molecules, which introduce electronic coupling between the inorganic metal-halide and organic sublattices. Realizing these functionalities requires an understanding of how this coupling is achieved and how it affects exciton behavior.

Influence of anchoring group on charge transport across self-assembled monolayer-based molecular tunnel junctions.

Predicting the charge transport rate, mechanism and dielectric response of solid-state molecular electronics is challenging since these properties depend on many variables such as molecular backbone, electrode material, junction contact geometry, anchoring and terminal functional groups, and so on. Although the effects of the anchoring group (X) on the conductance of single-molecule junctions have been widely investigated, in large-area junctions examples are rare, although the latter makes it possible to also explore the role of dielectric properties on charge transport rates. Here we report a change of 2.

Scalable photonic quantum technologies.

Photonic quantum technologies are now progressing from demonstrations of fundamental phenomena to systems of sufficient scale and quality to enable practical applications with quantum advantage in communications, computation and metrology. Here we review recent advances in quantum optics that have led to the emergence of such scalable quantum technologies, and outline the road ahead to more general applications with greater potential impact. We first focus on the components that support various photonic quantum applications, including quantum light sources, linear-optical networks and detectors.

Resonant scattering in low energy electron diffraction: Bi/Ni(111).

We report Low Energy Electron Diffraction (LEED) diffraction patterns measured at energies up to 50 eV for a monolayer thick Bi film on Ni(111). Surprisingly, the intensity versus energy profiles of several from the ten unique (i.e.

Boosting the Charge Output of Enclosed Liquid-Based Nanogenerators by Electrowetting-Assisted Charge Injection Approach.

Liquid-based nanogenerators (L-NGs) have emerged as a promising solution for clean energy, appreciated for their minimal friction and effective contact at solid-liquid interfaces. Enclosed L-NGs, in particular, offer the benefits of enhanced durability and versatility. However, a key issue with enclosed L-NGs is the low charge density resulting from triboelectrification at the liquid-solid interface.

Comparative life cycle assessment of lead-free halide perovskite composites/polymer for piezoelectric energy harvesting.

Lead zirconate titanate (PZT) is one of the most widely used piezoelectric materials due to its excellent performance. However, its lead content raises serious environmental and health concerns, prompting the search for more sustainable alternatives. In this work, we explore whether a lead-free composite based on the halide perovskite FASnI embedded in a polyvinylidene fluoride (PVDF) matrix could serve as a viable substitute for PZT in piezoelectric energy harvesting applications.

Hydroxylamine: an overseen intermediate that brings into question nitrogen selectivity in metal-catalyzed nitrate and nitrite reduction.

In decades of nitrate and nitrite hydrogenation research, nitrite, ammonia, and nitrogen gas were assumed to be the only relevant products. However, we have discovered hydroxylamine on several metal catalysts under various reaction conditions using a simple derivatization strategy based on the oximation of benzaldehyde with hydroxylamine. This previously overlooked intermediate challenges pervasive assumptions of nitrogen gas selectivity and compels a reexamination of the reaction mechanism.

Optimizing excited states in quantum Monte Carlo: A reassessment of double excitations.

Quantum Monte Carlo (QMC) methods have proven to be highly accurate for computing excited states, but the choice of optimization strategies for multiple states remains an active topic of investigation. In this work, we revisit the calculation of double excitation energies in nitroxyl, glyoxal, tetrazine, and cyclopentadienone, exploring different objective functionals and their impact on the accuracy and robustness of QMC. A previous study for these systems employed a penalty functional to enforce orthogonality among the states, but the chosen prefactors did not strictly ensure convergence to the target states.

Understanding the Light-Driven Enhancement of CO Hydrogenation over Ru/TiO Catalysts.

Ru/TiO catalysts are well known for their high activity in the hydrogenation of CO to CH (the Sabatier reaction). This activity is commonly attributed to strong metal-support interactions (SMSIs), associated with reducible oxide layers partly covering the Ru-metal particles. Moreover, isothermal rates of formation of CH can be significantly enhanced by the exposure of Ru/TiO to light of UV/visible wavelengths, even at relatively low intensities.

Chiral Phonons in 2D Halide Perovskites.

Phonons in chiral crystal structures can be circularly polarized, making them chiral. Chiral phonons carry angular momentum, which is observable in heat currents, and, via coupling to electron spin, in spin currents. Two-dimensional (2D) halide perovskites, versatile direct band gap semiconductors, can easily form chiral structures by incorporating chiral organic cations.

Oriented 2D Ruddlesden-Popper metal halides by pulsed laser deposition.

Two-dimensional (2D) Ruddlesden-Popper (RP) metal halides present unique and tunable properties. However, direct and oriented synthesis is challenging due to low formation energies that lead to rapid, uncontrolled growth during solution-based processing. Here, we report the solvent-free growth of oriented  = 1 (PEA)PbI RP films by pulsed laser deposition (PLD).

Correlating reductive vanadium oxide transformations with electrochemical N activation and ammonia formation.

The electrochemical reduction of nitrogen to ammonia (E-NRR) could become an environmentally friendly approach, yet its molecular-scale reaction mechanisms remain difficult to elucidate. Here, we use electrochemical infrared reflection-absorption spectroscopy (EC-IRRAS) to examine vanadium oxide electrodes in neutral aqueous electrolyte (pH 7). XPS reveals that the vanadium oxide electrode initially consists predominantly of V species in the form of VO.

Dual role of electrical stimulation and a biomimetic matrix in neural differentiation within a microfluidic platform.

Neurodegenerative diseases mostly stem from oxidative stress and/or misfolded proteins in the central and peripheral nervous systems, posing clinical and economic burdens globally. Despite the advances in this field, biomimetic models recapitulating the neural microphysiological environment of both patients and healthy individuals are needed to accelerate drug development. Herein, a biomimetic microfluidic platform was developed to promote neural differentiation of stem cells by recapitulating physicochemical and physicomechanical factors in the neural microenvironment.

Odd-even effects in lead-iodide-based Ruddlesden-Popper 2D perovskites.

Two-dimensional (2D) halide perovskites are a versatile material class, exhibiting a layered crystal structure, consisting of inorganic metal-halide sheets separated by organic spacer cations. Unlike their 3D counterparts, 2D perovskites have less strict geometric requirements, allowing for a wider range of molecules to be incorporated. This potentially offers a way to engineer the properties of a 2D perovskite through adequate selection of the organic spacer cations.

Tracing Ion Migration in Halide Perovskites with Machine Learned Force Fields.

Halide perovskite optoelectronic devices suffer from chemical degradation and current-voltage hysteresis induced by migration of highly mobile charged defects. Atomic scale molecular dynamics simulations can capture the motion of these ionic defects, but classical force fields are too inflexible to describe their dynamical charge states. Using CsPbI as a case study, we train machine learned force fields from density functional theory calculations and study the diffusion of charged halide interstitial and vacancy defects in bulk CsPbI.

Ultrafast Light-Driven Electronic and Structural Changes in LaFeO Perovskites Probed by Femtosecond X-Ray Absorption Spectroscopy.

Conducting real-time, element-specific studies of photo-excited systems is a long-standing challenge. The development of X-ray free-electron lasers (XFELs) has paved the way for the emergence of a promising technique: femtosecond X-ray absorption spectroscopy (fs-XAS). This powerful technique reveals electronic and geometric characteristics, providing unprecedented insight into their dynamic interactions under nonequilibrium conditions.

Cs-Bentonite Clay for Biogas Upgrading: A Numerical Assessment.

Biogas upgrading by vacuum-pressure swing adsorption involves the selective adsorption of CO over CH on a sorbent material to separate both components. This work assesses numerically the performance of the previously characterized Cs-exchanged bentonite clay for this separation. This benchmarking study includes the effect of the process cycle configuration (seven different configurations using one stage and up to three columns), the ambient temperature (15 or 25 °C), the feed biogas composition (CO mole fraction of 0.

CO Adsorption on Variably Hydrated Cation-Exchanged Montmorillonite-Rich Clays.

Layered swelling clay minerals like montmorillonite (MMT) can competitively and synergistically adsorb CO and HO in their interlayer galleries. This work examines how different interlayer cations, relative humidity levels (and amount of cosorbed HO), and (de)hydration history affect CO adsorption on MMT and MMT-rich bentonite at near-ambient pressure and temperature. For CO to be adsorbed, the MMT requires either large (e.

Effects of Nuclear Motion on the Photoinduced Interfacial Charge Transfer Dynamics at a NiO/P1 Photocathode.

The performance of dye-sensitized photoelectrochemical cells is presently limited by the photocathode component. Here, we investigate the impact of nuclear dynamics on the photoinduced charge separation of the benchmark NiO/P1 system (P1 = 4-(bis-4-(5-(2,2-dicyano-vinyl)-thiophene-2-yl)-phenyl-amino)-benzoic acid). Transient absorption (TA) studies in aqueous environments with different viscosities show that photoinduced hole injection either proceeds ultrafast (<100 fs) or in a sub-ps time window.

Polyelectrolyte complex-based materials for separations: progress, challenges and opportunities.

Polyelectrolyte complex (PEC) based materials could provide a sustainable alternative to conventional materials, especially for separation applications. However, reproducible production remains a challenge due to the many parameters influencing the polyelectrolyte complexation process, eventually affecting the properties and performance of the final material. Here, we provide an overview of how different parameters affect polyelectrolyte complexation and discuss promising PEC-based materials for separation applications, , porous membranes, functional and barrier coatings, adhesives, saloplastics, and extraction media.