Misfit layer compounds (MLCs) are a versatile platform for exploring the electronic phase diagram of two dimensional (2D) materials beyond the limits of conventional gating techniques. This work demonstrates the precise tunability of electron doping in NbSe2 monolayers through chemical alloying within the rocksalt layer of (LaxPb1xSe)1.14(NbSe2)2 heterostructures. By combining first principles density functional theory (DFT) calculations with angle resolved photoemission spectroscopy (ARPES), we prove that the rocksalt unit acts as an universal electron donor. We show that varying the La Pb ratio results in a rigid Fermi level shift, still preserving the NbSe2 electronic structure. Crucially, photon energy dependent ARPES confirms that the NbSe2 layers nearly maintain their intrinsic 2D character and orbital identity within the three dimensional misfit. This study establishes MLCs as a reliable platform for engineering emergent states in 2D transition metal dichalcogenides through precise stoichiometric control.
We present a tabletop method to investigate how tailored laser excitation can enhance shock wave generation in water. By delivering two spatiotemporally separated laser pulses focused into a confined liquid layer, we identify an optimized excitation condition that maximizes the resulting shock pressure. Remarkably, dual-pulse laser excitation leads to an overall shock pressure that far exceeds the sum of the shock pressures generated by the individual pulses. This nonlinear amplification reveals a previously unexploited laser-matter interaction regime that overcomes saturation limits in laser-driven shock generation.
An accurate estimation of the molecular abundances of isomers in the interstellar medium (ISM) is necessary to unravel the underlying chemistry and physics. After the recent detection of both isomers of formic acid (cis- and trans-HCOOH) in dense dark cold clouds, their accurate molecular line modeling became of interest. The conditions of these environments do not necessarily follow the local thermodynamic equilibrium, thus taking into account the competition between the radiative and collisional processes is required. This involves knowledge of the rotational excitation data for collisions with the most abundant interstellar species - He and H2. In this paper, the first potential energy surface (PES) for the interaction of formic acid with He atoms is computed using the explicitly correlated coupled-cluster theory [CCSD(T)-F12]. The obtained interaction potentials for the two rotamers demonstrate qualitative similarities and high anisotropy. The global minima are found with V = -53.0 cm-1 and V = -46.0 cm-1 for cis-HCOOH and trans-HCOOH, respectively. Collisional excitation cross sections calculated for total energies up to 100 cm-1 demonstrate similar propensity rules for both isomers. Quantitative differences between the cross sections associated with the two rotamers are also discussed.
Carbon hydrides play a crucial role in the formation of complex organic molecules in highly UV illuminated regions of the interstellar medium (ISM). The formation of CH+ is the first step in the reactions leading to the formation of various carbon hydrides. CH+ formation is relatively well understood with strong agreement between theoretical and experimental results. However, its destruction by collision with the H atom, at low temperatures of interest in the ISM, is in contrast still not well understood and there is a large discrepancy between theoretical and experimental data [R. Plasil et al., AstroPhys. J., 2011, 737, 1], which are almost an order of magnitude smaller than various classical and quantum mechanical calculations. In this work we have computed and fitted a new set of non-adiabatic potential energy surfaces (PES) for the title system, including the three lower adiabatic states. We then investigate three possible sources of disagreement with the experimental results: non-adiabatic effects from regions near the conical intersections, and rotational and vibrational excitation of the CH+ molecule. We conclude that vibrational excitation of the CH+ plays a major role in reducing the reactivity at low temperatures, and we raise the question of whether vibrational thermalization of the CH+ is not fully achieved in the experiment. Such non-thermalized conditions could explain the decrease of the measured reaction rate constant.
Laser cutting is an old and multi-physical process that was quickly adopted by the metallurgical industry. However, this fast industrialisation has had a significant impact on quality control. Several studies have been carried out to characterise and minimise different types of cutting defects. Reviews published between 2008 and 2022 highlight that research often focuses on single-criterion ___quality' approaches, aiming to minimise specific defects such as the Heat-Affected Zone, surface roughness, or kerf geometry. Consequently, efforts have been directed at optimising specific aspects of quality rather than adopting a complete approach. Furthermore, these reviews reveal that cutting quality can be enhanced through the careful selection of laser manufacturing parameters and part parameters. However, while parameters such as material and thickness have been investigated, the influence of part morphology on cutting quality remains underexplored.___ Although some studies have examined the effects of material and thickness, part morphology is often limited to simple segments with varying cutting lengths or angles. While other research has investigated the impact of angle size on cutting quality, no established method exists to systematically determine the influence of each part morphology on cutting quality.______ In response to this gap, the present study proposes to evaluate the criticality of cutting defects, as defined by existing standards, across various part morphologies using a method adapted from Failure Modes, Effects, and Criticality Analysis (FMECA). The objective is to develop a global approach that examines the influence of all morphologies on all types of cutting defects. An industrial application shows that cutting defects, particularly thermal ones, are strongly influenced by morphologies, while thickness affects them irregularly. Improvement priorities target critical defects shaped by both factors. Burrs and adherent slag are critical in angles and arcs, while segments, often used in studies, are less sensitive._________ These observations lead to the definition of design limits. This method offers a detailed analysis of the influence of design data on quality, providing practical tools for improving industrial processes._________
