State Energy Research Articles

Held v State of Montana: A Constitutional Rights Turn in Climate Change Litigation?

Abstract This analysis examines the decision in Held v State of Montana by the Montana First Judicial District Court, in which 16 youth plaintiffs successfully argued that provisions within the state energy policy and the Montana Environmental Policy Act (MEPA) violate their constitutional right to a clean and healthful environment. As the first climate case in the USA to be brought based on a constitutional right to a healthy environment, it has received considerable attention and is being hailed as a landmark victory. This analysis examines the case in the context of recent trends in climate change litigation and argues that whilst the decision is indeed noteworthy, the circumstances that led to the decision make it unlikely that a wave of similarly successful claims will follow in the USA. Nevertheless, the case could mark a so-called ‘constitutional rights turn’ in climate litigation, as the case bolsters support for stronger protections for environmental rights.

Robust topological bound states in the continuum in a quantum Hall bar with an anti-dot

Bound states in the continuum (BICs) are quantum states with normalizable wave functions and energies that lie within the continuous spectrum for which extended or dispersive states are also available. These special states, which have shown great applicability in photonic systems for devices such as lasers and sensors, are also predicted to exist in electronic low-dimensional solid-state systems. The non-trivial topology of materials is within the known mechanisms that prevent the bound states to couple with the extended states. In this work we search for topologically protected BICs in a quantum Hall bar with an anti-dot formed by a pore far from the borders of the bar. The bound state energies and wavefunctions are calculated by means of the Recursive S-Matrix method. The resulting bound state energies coexist with extended states and exhibit a pattern complimentary to the Hofstadter butterfly. A symmetry-breaking diagonal disorder was introduced, showing that the BICs with energies far from the Landau levels remain robust. Moreover, the energy difference between consecutive BICs multiplied by the anti-dot perimeter follows the same curve despite disorder. Finally, a BIC-mediated current switching effect was found in a multi-terminal setup for zero and finite temperature, which might permit their experimental detection.

Helicene Covalent Organic Frameworks for Robust Light Harvesting and Efficient Energy Transfers.

Helicenes represent a class of fascinating π compounds with fused yet folded backbones. Despite their broad structural diversity, harnessing helicenes to develop well-defined materials is still a formidable challenge. Here we report the synthesis of crystalline porous helicene materials by exploring helicenes to synthesize covalent 2D lattices and layered π frameworks. Topology-directed polymerization of [6]helicenes and porphyrin creates 2D covalent networks with alternate helicene-porphyrin alignment along the x and y directions at a 1.5-nm interval and develops [6]helicene frameworks through reversed anti-AA stack along the z direction to form segregated [6]helicene and porphyrin columnar π arrays. Notably, this π configuration enables the frameworks to be highly red luminescent with benchmark quantum yields. The [6]helicene frameworks trigger effieicnt intra-framework singlet-to-singlet state energy transfer from [6]helicene to porphyrin and facilitate intermolecular triplet-to-triplet state energy transfer from frameworks to molecular oxygen to produce reactive oxygen species, harvesting a wide range of photons from ultraviolet to near-infrared regions for light emitting and photo-to-chemical conversion. This study introduces a new family of extended frameworks, laying the groundwork for exploring well-defined helicene materials with unprecedented structures and functions.

Robust Effective Ground State in a Nonintegrable Floquet Quantum Circuit

An external periodic (Floquet) drive is believed to bring any initial state to the featureless infinite temperature state in generic nonintegrable isolated quantum many-body systems in the thermodynamic limit, irrespective of the driving frequency Ω. However, numerical or analytical evidence either proving or disproving this hypothesis is very limited and the issue has remained unsettled. Here, we study the initial state dependence of Floquet heating in a nonintegrable kicked Ising chain of length up to L=30 with an efficient quantum circuit simulator, showing a possible counterexample: the ground state of the effective Floquet Hamiltonian is exceptionally robust against heating, and could stay at finite energy density even after infinitely many Floquet cycles, if the driving period is shorter than a threshold value. This sharp energy localization transition or crossover does not happen for generic excited states. The exceptional robustness of the ground state is interpreted by (i) its isolation in the energy spectrum and (ii) the fact that those states with L-independent ℏΩ energy above the ground state energy of any generic local Hamiltonian, like the approximate Floquet Hamiltonian, are atypical and viewed as a collection of noninteracting quasiparticles. Our finding paves the way for engineering Floquet protocols with finite driving periods realizing long-lived, or possibly even perpetual, Floquet phases by initial state design. Published by the American Physical Society 2024

Position of substituents directs the electron transfer properties of entatic state complexes: new insights from guanidine-quinoline copper complexes.

In a previous study, we showed that the properties and the ability as an entatic state model of copper guanidine quinoline complexes are significantly influenced by a methyl or methyl ester substituent in the 2-position. To prove the importance of the 2-position of the substituent, two novel guanidine quinoline ligands with a methyl or methyl ester substituent in the 4-position and the corresponding copper complexes were synthesized and characterized in this study. The influence of the substituent position on the copper complexes was investigated with various experimental and theoretical methods. The molecular structures of the copper complexes were examined in the solid state by single-crystal X-ray diffraction (SCXRD) and by density functional theory (DFT) calculations indicating a strong dependency on the substituent position compared to the systems substituted in the 2-position from the previous study. Further, the significantly different influence on the donor properties in dependency on the substituent position was analyzed with natural bond orbital (NBO) calculations. By the determination of the redox potentials, the impact on the electrochemical stabilization was examined. With regard to further previously analyzed guanidine quinoline copper complexes, the electrochemical stabilization was correlated with the charge-transfer energies calculated by NBO analysis and ground state energies, revealing the substituent influence and enabling a comparatively easy and accurate possibility for the theoretical calculation of the relative redox potential. Finally, the electron transfer properties were quantified by determining the electron self-exchange rates via the Marcus theory and by theoretical calculation of the reorganization energies via Nelsen's four-point method. The results gave important insights into the dependency between the ability of the copper complexes as entatic state model and the type and position of the substituent.

Benchmarking of machine learning interatomic potentials for reactive hydrogen dynamics at metal surfaces

Simulations of chemical reaction probabilities in gas surface dynamics require the calculation of ensemble averages over many tens of thousands of reaction events to predict dynamical observables that can be compared to experiments. At the same time, the energy landscapes need to be accurately mapped, as small errors in barriers can lead to large deviations in reaction probabilities. This brings a particularly interesting challenge for machine learning interatomic potentials, which are becoming well-established tools to accelerate molecular dynamics simulations. We compare state-of-the-art machine learning interatomic potentials with a particular focus on their inference performance on CPUs and suitability for high throughput simulation of reactive chemistry at surfaces. The considered models include polarizable atom interaction neural networks (PaiNN), recursively embedded atom neural networks (REANN), the MACE equivariant graph neural network, and atomic cluster expansion potentials (ACE). The models are applied to a dataset on reactive molecular hydrogen scattering on low-index surface facets of copper. All models are assessed for their accuracy, time-to-solution, and ability to simulate reactive sticking probabilities as a function of the rovibrational initial state and kinetic incidence energy of the molecule. REANN and MACE models provide the best balance between accuracy and time-to-solution and can be considered the current state-of-the-art in gas-surface dynamics. PaiNN models require many features for the best accuracy, which causes significant losses in computational efficiency. ACE models provide the fastest time-to-solution, however, models trained on the existing dataset were not able to achieve sufficiently accurate predictions in all cases.

Sulfonylurea receptor coupled conductances alter the performace of two central pattern generating circuits in Cancer borealis.

Neuronal activity and energy supply must maintain a fine balance for neuronal fitness. Various channels of communication between the two could impact network output in different ways. Sulfonylurea receptors (SURs) are a modification of ATP-binding cassette proteins (ABCs) that confer ATP-dependent gating on their associated ion channels. They are widely expressed and link metabolic states directly to neuronal activity. The role they play varies in different circuits, both enabling bursting and inhibiting activity in pathological conditions. The crab, Cancer borealis, has central patterns generators (CPGs) that fire in rhythmic bursts nearly constantly and it is unknown how energy availability influences these networks. The pyloric network of the stomatogastric ganglion (STG) and cardiac ganglion (GC) control rhythmic contractions of the foregut and heart respectively. Pharmacological manipulation of SURs results in opposite effects in the two CPGs. Neuronal firing completely stops in the STG when SUR-associated channels are open, and firing increases when the channels are closed. This results from a decrease in the excitability of pyloric dilator (PD) neurons, which are a part of the pacemaker kernel. The neurons of the CG, paradoxically, increase firing within bursts when SUR-associated channels are opened, and bursting slows when SUR-associated channels are closed. The channel permeability and sensitivities analyses present novel SUR-conductance biophysics, which nevertheless change activity in ways reminiscent of the predominantly studied mammalian receptor/channels. We suggest that SUR-associated conductances allow different neurons to respond to energy states in different ways through a common mechanism.

A DFT study on catalytic cracking mechanism of tar by Ni or Fe doped CaO during biomass steam gasification

The presence of byproduct tar seriously reduces the efficiency and syngas quality in the biomass gasification process. The current understanding of CaO-catalyzed tar cracking mainly depends on experimental findings and conjecture about CaO properties. However, there is a significant lack of simulation studies that explore the conversion mechanism at the molecular level. In this work, the reaction mechanism of tar catalytic cracking on Ni or Fe doped CaO was studied using density functional theory simulation. The benzene, phenol and toluene were chosen as the tar model compounds to determine the influences of Ni and Fe on the adsorption characteristics of CaO surface. CaO doped with Ni and Fe increases its electron affinity and electron conductivity from 4.99 to 9.21/5.58 eV-1. It also enhances the interactions between the d-orbitals of Ni/Fe atoms and the p-orbitals of O atoms. The C-H activation of ·CH3 is the most kinetically and energetically feasible first step. The Ni-doped CaO and Fe-doped CaO decrease the energy barriers by 15.7 % and 21.7 %, respectively, compared with undoped CaO. Ni enhances the surface adsorption capacity for ·H radicals to form OH* at the O top site, whereas Fe promotes the stabilization of ·H radicals at the Ca-O vacancy. Through the enhancement of chemical adsorption capacity, improvement of electronic properties, introduction of electron reorganization and orbital hybridization, low-energy shift of energy levels, and generation of new energy states (from -0.85 to -1.64/-3.05 eV), the surfaces of Ni-doped CaO and Fe-doped CaO provide a favorable electronic environment for the tar catalytic cracking, which improves the reaction efficiency and selectivity.

Acetylation, ADP-ribosylation and methylation of malate dehydrogenase.

Metabolism within an organism is regulated by various processes, including post-translational modifications (PTMs). These types of chemical modifications alter the molecular, biochemical, and cellular properties of proteins and allow the organism to respond quickly to different environments, energy states, and stresses. Malate dehydrogenase (MDH) is a metabolic enzyme that is conserved in all domains of life and is extensively modified post-translationally. Due to the central role of MDH, its modification can alter metabolic flux, including the Krebs cycle, glycolysis, and lipid and amino acid metabolism. Despite the importance of both MDH and its extensively post-translationally modified landscape, comprehensive characterization of MDH PTMs, and their effects on MDH structure, function, and metabolic flux remains underexplored. Here, we review three types of MDH PTMs - acetylation, ADP-ribosylation, and methylation - and explore what is known in the literature and how these PTMs potentially affect the 3D structure, enzymatic activity, and interactome of MDH. Finally, we briefly discuss the potential involvement of PTMs in the dynamics of metabolons that include MDH.

Effect of Pyrrolidinedithiocarbamate Ligand on the Luminescence Properties of Heteroligand Samarium and Europium Complexes: Experimental and Theoretical Study.

The photophysical properties of two isostructural heteroligand lanthanide complexes of general formula Ln(pdtc)3(phen) (pdtc = pyrrolidinedithiocarbamate anion, phen = 1,10-phenanthroline), Ln = Sm3+ (1), Eu3+ (2)) were studied in solid state and dichloromethane (DCM) solution. The two lanthanide complexes were investigated by experimental techniques for structural (single-crystal X-ray diffraction analysis of 1, powder XRD, TG-DTA) and spectroscopic [electron paramagnetic resonance (EPR), infrared (IR), ultraviolet-visible (UV-vis), photoluminescence (PL)] characterization. DFT/TDDFT/ωB97xD and multireference SA-CASSCF/NEVPT2 calculations with perturbative spin-orbit coupling corrections were applied to construct the Jablonski energy diagrams and to discuss the excited state energy transfer mechanism with competing excited state processes and possible sensitized mechanism of metal-centered emission. The first excited state (S1) involved in the excited state energy transfer L(antenna)-to-Ln was predicted to have interligand (pdtc-to-phen) charge transfer character in contrast to the previously predicted ligand-to-metal charge transfer character. The theoretical consideration showed similar relaxation paths and luminescence quenching channels and appropriate Donor*(phen)-Acceptor*(Ln3+) energy gap for 1 and 2. The experimental measurements in the solid state, however, showed efficient luminescence and good ability to convert UV to visible light only for the Sm(pdtc)3(phen) complex. The minor emission of 2 was explained by partial reduction of Eu3+, confirmed by EPR and calculated electron density distribution data.

Impact of electronic correlation on strong laser-induced bound-state transitions

Electron correlation (EC) plays a crucial role in all multi-electron systems and dynamic processes. In this work, we focus on strong laser-induced bound-bound transitions (BBT), which are fundamental to optical absorption measurements. We use the helium atom, the simplest two-electron system, as our test case, utilizing the ab initio code package HeTDSE. We examined the bound state energy levels, transition dipole moments (TDMs), and the dynamics of strong laser-induced BBT, both with and without considering EC. Our results indicate that EC significantly impacts the energy levels of the bound states and the TDMs. These effects collectively influence the transition dynamics of the excited states. Although EC does not alter the quantum transition pathways between resonance states, it generally increases the probability of resonance transitions in most cases. Our findings provide a quantitative description of EC in laser-induced BBT.

Machine Learning in the Problem of Extrapolating Variational Calculations in Nuclear Physics

A modified machine learning method is proposed, utilizing an ensemble of artificial neural networks for the extrapolation of energies obtained in variational calculations, specifically in the No-core Shell Model (NCSM), to the case of the infinite basis. A new neural network topology is employed, and criteria for selecting both the data used for training and the trained neural networks for statistical analysis of the results are formulated. The approach is tested by extrapolating the deutron ground state energy in calculations with the Nijmegen II NN interaction and provides statistically significant results. This technique is applied to obtain extrapolated ground state energies of 6Li and 6He nuclei based on the NCSM calculations with Daejeon16 NN interaction.

Complete critical bound region of the generalized exponential cosine screened Coulomb potential

The complete critical bound region of the generalized exponential cosine screened Coulomb potential (ECSCP) V(r)=−r−1e−(βcos⁡θ)rcos⁡[(βsin⁡θ)r] is investigated by employing the generalized pseudospectral method. Highly accurate critical screening parameters are determined over the entire parameter space, spanning from the exponential screened Coulomb potential (θ = 0), via the oscillatory ECSCP ( θ=π/4 ), to the strongest oscillatory cosine Coulomb potential (CCP) ( θ=π/2 ). With an efficient extrapolation technique, the critical screening parameter for the CCP is estimated at about βc=2.34 . By analyzing the variation of the ground state energy in the critical bound region, we separate the parameter space into two regions, i.e. the exponential region at small and moderate values of θ where the exponential screening term dominates the critical behavior of system, and the cosine region for θ close to π/4 where the oscillatory cosine term dominates.

Ti‐Doped ZnO Thin Films‐Based Transparent Photovoltaic for High‐Performance Broadband and Wide‐Field‐of‐View Photocommunication Window

Transparent photovoltaics (TPVs) are crucial for developing next‐generation see‐through electronics. However, TPV devices (TPVDs) require wide‐bandgap materials that are typically only responsive to short wavelength (ultraviolet, UV) lights rather than visible lights. Is it possible to improve the TPV performance by harvesting the longer wavelength lights without degradation of transparency? It may be satisfied with the function of intermediate energy states, which can utilize the lower photon energy (longer wavelength light) by a two‐step transition. To achieve this, co‐sputtered Ti‐doped ZnO (Ti:ZnO) film‐based high‐performance TPVDs have been developed. Density functional theory analysis revealed the formation of intermediate energy states due to the hybridization of O 2p and Ti 3d orbitals in the Ti:ZnO system. The Ti:ZnO‐based TPVDs show 65% average visible transparency with a power production value of 655 μW cm−2. These devices exhibit good photodetection behavior under UV to visible illuminations with high responsivity and detectivity values of 1.85 A W−1 and 2.5 × 1013 Jones, respectively. Finally, a high‐performance UV to visible broadband and wide‐field‐of‐view photocommunication system is designed based on the TPVDs to generate the fast Morse code signal. Therefore, Ti doping in ZnO provides a good way to improve the device's functionality for futuristic applications.

Exchange Energy of the Ferromagnetic Electronic Ground State in a Monolayer Semiconductor

Mobile electrons in the semiconductor monolayer MoS2 form a ferromagnetic state at low temperature. The Fermi sea consists of two circles: one at the K point, the other at the K˜ point, both with the same spin. Here, we present an optical experiment on gated MoS2 at low electron density in which excitons are injected with known spin and valley quantum numbers. The resulting trions are identified using a model which accounts for the injection process, the formation of antisymmetrized trion states, electron-hole scattering from one valley to the other, and recombination. The results are consistent with a complete spin polarization. From the splittings between different trion states, we measure the exchange energy Σ, the energy required to flip a single spin within the ferromagnetic state, as well as the intervalley Coulomb exchange energy J. We determine Σ=11.2 meV and J=5 meV at n=1.5×1012 cm−2 and find that J depends strongly on the electron density n. Published by the American Physical Society 2024

Governments and the Private Energy Sector: Analysis of Energy Sector and Relationship between State

A symbiotic relationship exists between the state and the energy sector that often leads to conflicting relationships between the two. The best example of this complicated relationship is between the state and free markets is the case of the United States, European Union, and Global Energy Sector. The decline in the gas import—due to sanctions placed on the Russian Federation—to Europe from Russia, along with other counties that import gas from Russia, has negatively affected the economies of European counties. The Russian government has restructured the exporting of gas to other counties in order to continue to sustain companies’ growth. This literature review will analyze how sanctions against Russian Federation have affected the energy market and how it will affect entire energy markets.

Nonadiabatic Molecular Dynamics in Momentum Space Beyond Harmonic Approximation: Hot Electron Relaxation in Photoexcited Black Phosphorus.

We simulated hot-electron relaxation in black phosphorus using the nonadiabatic molecular dynamics (NA-MD) approach with a non-Condon effect in momentum space beyond the harmonic approximation. By comparing simulations at the Γ point in a large supercell with those using a few k-points in a smaller supercell─while maintaining the same number of electronic states within the same energy range, we demonstrate that both setups yield remarkably consistent energy relaxation times, regardless of the initial state energy. This consistency arises from the complementary effects of supercell size in real space and the number of k-points in the reciprocal space. This finding confirms that simulations at a single k-point in large size supercells are an effective approximation for NA-MD with a non-Condon effect. This approach offers significant advantages for complex photophysics, such as intervalley scattering and indirect bandgap charge recombination, and is particularly suitable for large systems without the need for a harmonic approximation.

Nonadiabatic Molecular Dynamics in Momentum Space Beyond Harmonic Approximation: Hot Electron Relaxation in Photoexcited Black Phosphorus.

We simulated hot-electron relaxation in black phosphorus using the nonadiabatic molecular dynamics (NA-MD) approach with a non-Condon effect in momentum space beyond the harmonic approximation. By comparing simulations at the Γ point in a large supercell with those using a few k-points in a smaller supercell─while maintaining the same number of electronic states within the same energy range, we demonstrate that both setups yield remarkably consistent energy relaxation times, regardless of the initial state energy. This consistency arises from the complementary effects of supercell size in real space and the number of k-points in the reciprocal space. This finding confirms that simulations at a single k-point in large size supercells are an effective approximation for NA-MD with a non-Condon effect. This approach offers significant advantages for complex photophysics, such as intervalley scattering and indirect bandgap charge recombination, and is particularly suitable for large systems without the need for a harmonic approximation.

Accurate NMR Shieldings with σ-Functionals.

In recent years, density-functional methods relying on a new type of fifth-rung correlation functionals called σ-functionals have been introduced. σ-Functionals are technically closely related to the random phase approximation and require the same computational effort but yield distinctively higher accuracies for reaction and transition state energies of main group chemistry and even outperform double-hybrid functionals for these energies. In this work, we systematically investigate how accurate σ-functionals can describe nuclear magnetic resonance (NMR) shieldings. It turns out that σ-functionals yield very accurate NMR shieldings, even though in their optimization, exclusively, energies are employed as reference data and response properties such as NMR shieldings are not involved at all. This shows that σ-functionals combine universal applicability with accuracy. Indeed, the NMR shieldings from a σ-functional using input orbitals and eigenvalues from Kohn-Sham calculations with the exchange-correlation functional of Perdew, Burke and Ernzerhof (PBE) turned out to be the most accurate ones among the NMR shieldings calculated with various density-functional methods including methods using double-hybrid functionals. That σ-functionals can be used for calculating both reliable energies and response properties like NMR shieldings characterizes them as all-purpose functionals, which is appealing from an application point of view.

Experimentally Delineating the Catalytic Effect of a Single Water Molecule in the Photochemical Rearrangement of the Phenylperoxy Radical to the Oxepin-2(5H)-one-5-yl Radical.

Catalysis plays a pivotal role in both chemistry and biology, primarily attributed to its ability to stabilize transition states and lower activation free energies, thereby accelerating reaction rates. While computational studies have contributed valuable mechanistic insights, there remains a scarcity of experimental investigations into transition states. In this work, we embark on an experimental exploration of the catalytic energy lowering associated with transition states in the photorearrangement of the phenylperoxy radical-water complex to the oxepin-2(5H)-one-5-yl radical. Employing matrix isolation spectroscopy, density functional theory, and post-HF computations, we scrutinize the (photo)catalytic impact of a single water molecule on the rearrangement. Our computations indicate that the barrier heights for the water-assisted unimolecular isomerization steps are approximately 2-3 kcal mol-1 lower compared to the uncatalyzed steps. This decrease directly coincides with the energy difference in the required wavelength during the transformation (Δλ = λ546nm - λ579nm ≡ 52.4-49.4 = 3.0 kcal mol-1), allowing us to elucidate the differential transition state energy in the photochemical rearrangement of the phenylperoxy radical catalyzed by a single water molecule. Our work highlights the important role of water catalysis and has, among others, implications for understanding the mechanism of organic reactions under atmospheric conditions.