Abstract We present a quantum chemistry benchmark for noisy intermediate-scale computers that leverages the variational eigensolver, active-space reduction, reduced unitary coupled cluster ansatz, and density purification as error mitigation. demonstrate this using 4 of available qubits on 20-qubit IBM Tokyo 16-qubit Rigetti Aspen processors via simulation alkali metal hydrides (NaH, KH, RbH), with accuracy computed ground state energy serving primary metric. further parameterize suite trial...

The identification of isotopic labels by conventional macroscopic techniques lacks spatial resolution and requires relatively large quantities material for measurements. We recorded the vibrational spectra an α amino acid, l-alanine, with damage-free "aloof" electron energy-loss spectroscopy in a scanning transmission microscope to directly resolve carbon-site-specific real space nanoscale resolution. An red shift 4.8 ± 0.4 milli-electron volts C-O asymmetric stretching modes was observed...

The hydrodeoxygenation of methyl-substituted phenols was carried out in a flow microreactor at 300 degrees C and 2.85 MPa hydrogen pressure over sulfided CoMo/Al(2)O(3) catalyst. primary reaction products were benzene, cyclohexene, cyclohexane, H(2)O. Analysis the results suggests that two independent paths are operative, one leading to aromatics other partially or completely hydrogenated cyclohexanes. data analyzed using Langmuir-Hinshelwood kinetics extract values reactant-to-catalyst...

Deuterium, a stable hydrogen isotope, has been playing important roles in many scientific areas, including polymer science. The developments of deuteration science and have interwoven for the past 60 years. unique characteristics scattering lengths isotopes (protium deuterium) result dramatic differences length densities protiated deuterated compounds omnipresent polymers, rendering neutron powerful tool investigation polymeric structures dynamics that are inaccessible to other tools. While...

Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, possess unique physical chemical properties, enabling diverse applications in fields ranging from energy storage to communication, catalysis, sensing, healthcare, beyond. The nonmetallic atoms MXenes can exhibit distinct coordination environments, potentially leading a wide variety of 2D phases. Despite extensive research significant advancements, fundamental understanding MXenes' phase diversity its relationship...

Ionicity plays an important role in determining material properties, as well optoelectronic performance of organometallic trihalide perovskites (OTPs). Ion migration OTP films has recently been under intensive investigation by various scanning probe microscopy (SPM) techniques. However, controversial findings regarding the grain boundaries (GBs) associated with ion are often encountered, likely a result feedback errors and topographic effects common to SPM. In this work, electron...

Divide-Expand-Consolidate (DEC) is a local correlation method where the inherent locality of electron problem used to express correlated calculation on large molecular system in terms small independent fragment calculations employing subsets HF orbitals. A crucial feature DEC scheme that sizes orbital spaces are determined black box manner during calculation. In this way it ensured energy has been predefined precision compared conventional present work we apply calculate as well density...

The prevalent catalysts for natural and artificial N2 fixation are known to hinge upon transition-metal (TM) elements. Herein, we demonstrate by density functional theory that Al-doped graphene is a potential non-TM catalyst convert NH3 in the presence of relatively mild proton/electron sources. In integrated structure catalyst, Al atom serves as binding site catalytic center while framework an electron buffer during successive additions its various downstream NxHy intermediates. initial...

We demonstrate a scalable and energy-efficient hollow fiber membrane contactor (HFMC)-based process using green solvent for CO2 capture. This uses deep eutectic (DES) in an HFMC to provide close interfacial interactions contact between the DES CO2. approach overcomes disadvantages associated with direct absorption could potentially be applied variety of solvent-based capture methods. Commercial low-cost polymer membranes (e.g., microporous polypropylene) were evaluated reline, prototypical...

We study the hydrogen tunneling problem in a model system that represents active site of biological enzyme, soybean lipoxygenase-1. Toward this, we utilize quantum wavepacket dynamics performed on potential surfaces obtained by using hybrid density functional theory under influence dynamical site. The kinetic isotope effect is computed transmission amplitude wavepacket, and experimental value reproduced. By computing nuclear orbitals (eigenstates) along reaction coordinate, note for both...

Abstract We present the theoretical and implementation details of DFTB method with analytical gradients into Gaussian package. SCF optimization performance DIIS is compared modified Broyden Anderson methods, from which to be preferred. The number geometry steps can significantly decreased Berny algorithm conjugated gradient method. From comparison parameters as well trends in change HOMO LUMO energies, results show clearly that reproduce values obtained at B3LYP/6‐31G(d) level well. also...

Lithium wall conditioning has lowered hydrogenic recycling and dramatically improved plasma performance in many magnetic-fusion devices. In this Letter, we report quantum-classical atomistic simulations laboratory experiments that elucidate the roles of lithium oxygen uptake hydrogen amorphous carbon. Surprisingly, show creates a high concentration on carbon surface when bombarded by deuterium. Furthermore, oxygen, rather than lithium, plays key role trapping hydrogen.

For large molecular systems conventional implementations of second order Møller–Plesset (MP2) theory encounter a scaling wall, both memory- and time-wise. We describe how this wall can be removed. present massively parallel algorithm for calculating MP2 energies densities using the divide–expand–consolidate scheme where calculation on system is divided into many small fragment calculations employing local orbital spaces. The resulting linear-scaling with size, exhibits near perfect...

Abstract Quantum chemistry is a key application area for noisy‐intermediate scale quantum (NISQ) devices, and therefore serves as an important benchmark current future computer performance. Previous benchmarks in this field have focused on variational methods computing ground excited states of various molecules, including benchmarking suite the performance alkali‐hydrides under array error mitigation methods. State‐of‐the‐art to reach chemical accuracy hybrid quantum‐classical electronic...

We present the theory, implementation, and benchmarking of a real-time time-dependent density functional theory (RT-TDDFT) module within RMG code, designed to simulate electronic response molecular systems external perturbations. Our method offers insights into nonequilibrium dynamics excited states across diverse range systems, from small organic molecules large metallic nanoparticles. Benchmarking results demonstrate excellent agreement with established TDDFT implementations showcase...

The (TCNE)(2)(2)(-) dimer dianion formed by connecting two TCNE(-) anions via a four-center, two-electron pi-orbital bond is studied using ab initio theoretical methods and model designed to simulate the stabilization due surrounding counterions. examined as an isolated species in solvation environment representative of tetrahydrofuran (THF) solvent. intrinsic strength this novel influences internal Coulomb repulsions, solvent screening, counterion are all considered. geometry, electronic...

We present a novel first principles molecular dynamics scheme, called Liouville–von Neumann dynamics, based on equation for density matrices propagation and Magnus expansion of the time-evolution operator. The scheme combines formally accurate quantum electrons represented via classical nuclei. method requires few iterations per each time step where Fock operator is formed von integrated. algorithm (a) free constraint fictitious parameters, (b) avoids diagonalization operator, (c) can be...

A methodology to efficiently conduct simultaneous dynamics of electrons and nuclei is presented. The approach involves quantum wave packet using an accurate banded, sparse Toeplitz representation for the discrete free propagator, in conjunction with ab initio molecular treatment electronic classical nuclear degree freedom. latter may be achieved either by atom-centered density-matrix propagation or Born-Oppenheimer dynamics. two components methodology, namely, dynamics, are harnessed...

Over the past decade, open frame (``cagey'') structure of $\mathrm{CoS}{\mathrm{b}}_{3}$ skutterudite has invited intensive filling studies with various rare-earth elements for delivering state-of-the-art midtemperature thermoelectric performance. To rationalize previously reported experimental results and provide new insight into underexplored roles La fillers Sb vacancies, ab initio density functional theory studies, along semiclassical Boltzmann transport calculations, are performed...

We characterize the collision-induced fusion reaction of buckminsterfullerenes by means direct self-consistent-charge density-functional tight-binding molecular dynamics simulations. In agreement with experimental data, we find that highest probability is for collisions incident energy range 120--140 eV. this region, occurs way formation hot, vibrationally excited peanut-shaped structures within 1 ps. These nanopeanuts further undergo relaxation to short carbon nanotubes and are cooling...

A massively parallel, direct quantum molecular dynamics method is described. The combines a trajectory (QT) representation of the nuclear wave function discretized into an ensemble trajectories with electronic structure (ES) description electrons, namely using density functional tight binding (DFTB) theory. Quantum effects are included nuclei via corrections to classical forces. To reduce computational cost and increase numerical accuracy, resulting from localization computed approximately...

Irradiation dynamics of a single graphene sheet bombarded by hydrogen atoms is studied in the incident energy range 0.1 to 200 eV. Results for reflection, transmission, and adsorption probabilities, as well effects adsorbed atom electronic properties graphene, are obtained quantum-classical Monte Carlo molecular within self-consistent-charge-density functional tight binding formalism We compare these results with those, distinctly different, classical dynamics.PACS: 61.80.Az, 61.48.Gh,...