Density functional theory is used to show that the adhesion between single-walled carbon nanotubes (SWNTs) and catalyst particles from which they grow needs be strong support nanotube growth. It found Fe, Co, Ni, commonly catalyze SWNT growth, have larger strengths SWNTs than Cu, Pd, Au are therefore likely more efficient for supporting The calculations also maintain an open end of it necessary strength metal particle comparable cap formation energy end. This implies difference continued...

To distinguish between chemical bonding and physical binding is usually simple. They differ, in the normal case, both interaction strength (binding energy) length (structure). However, can be weak (e.g. some metallic bonding) strong due to permanent electrostatic moments, hydrogen binding, etc) making differentiation non-trivial. But since these are shared-electron or unshared-electron interactions, respectively, it principle possible type of by analyzing electron density around...

We report first-principle calculations of the recently synthesized Pb-free double perovskite Cs2PtI6, which we found to have potential be an excellent thermoelectric material, through investigation its electronic and phonon transport properties. The Heyd–Scuseria–Ernzerhof functional results in indirect band gap 1.40 eV, perfectly matching experiment. Our well-converged dispersion displays positive frequencies entire Brillouin zone hence confirms dynamic stability material. Further,...

Carbon nanotubes (CNTs), hollow cylinders of carbon, hold great promise for advanced technologies, provided their structure remains uniform throughout length. Their growth takes place at high temperatures across a tube-catalyst interface. Structural defects formed during alter CNT properties. These are believed to form and heal the interface but an understanding these mechanisms atomic-level is lacking. Here we present DeepCNT-22, machine learning force field (MLFF) drive molecular dynamics...

Based on first-principles calculations, the potential of holey graphyne is investigated for battery applications in terms storage capacity, volume expansion, diffusion barrier, and metal polysulfides binding. We found substantially higher capacities Li (873 mAh/g) Na (558 than typical graphite anodes (372 mAh/g <35 Na) other carbonaceous materials (450–750 200–500 Na). The migration barriers turn out to be 0.28 eV 0.32 eV, respectively, lower those theoretically reported commercial TiO2...

A combination of normal-incidence x-ray standing-wave (NIXSW) spectroscopy, photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and density-functional theory (DFT) has been used to investigate the interaction a number phthalocyanine molecules (specifically, SnPc, PbPc, CoPc) with Ag(111) surface. The metal-surface distances predicted by DFT calculations for SnPc/Ag(111) $(2.48\text{ }\text{\AA{}})$ CoPc/Ag(111) $(2.88\text{ are in good agreement our NIXSW experimental...

A fundamental understanding of the role catalysts in dehydrogenation MgH(2) nanoclusters is provided by carrying out first-principles calculations based on density functional theory. It shown that transition metal atoms Ti, V, Fe, and Ni not only lower desorption energies significantly but also continue to attract at least four hydrogen even when total content cluster decreases. In particular, Fe found migrate from surface sites interior during process, releasing more as it diffuses. This...

Platinum ditelluride (PtTe2) is an emerging semimetallic two-dimensional (2D) transition-metal dichalcogenide (TMDC) crystal with intriguing band structures and unusual topological properties. Despite much devoted efforts, scalable controllable synthesis of large-area 2D PtTe2 well-defined layer orientation has not been established, leaving its projected structure-property relationship largely unclarified. Herein, we report a low-temperature growth layers on area greater than few square...

Combining the SCAN and mBJ-LDA meta-GGA functionals of DFT facilitates accurate efficient computation physical properties photocatalysts which is either comparable or better than computationally expansive hybrid <italic>GW</italic> methods.

Adiabatic internal frequencies are compared with c-vector and intrinsic frequencies. It is shown that modes not suitable to characterize molecular fragments ϕn since they localized in their definition leads unreasonable frequency values. Intrinsic suffer from a strong dependence on the set of parameters chosen describe geometry molecule. Apart this, represent averaged frequencies, for which mass effects electronic properly separated. based dynamic principle, separate do depend any way...

The nitrogen-vacancy (NV) center in diamond has shown great promise for quantum information due to the ease of initializing qubit and reading out its state. Here we show leading mechanism these effects gives results opposite from experiment; instead both must rely on new physics. Furthermore, NV centers fabricated nanometer-sized clusters are stable, motivating a bottom-up approach, with possibility quite different optical properties bulk.

The nitrogen-vacancy (NV) center is a paramagnetic defect in diamond with applications as qubit. Here, we investigate its electronic structure by using ab initio density functional theory for five different NV models of two cluster sizes. We describe the symmetry and energetics low-lying states compare optical frequencies obtained to experimental results. compute major transition negatively charged centers within 25--100 meV accuracy find that it energetically favorable substitutional...

Density functional theory (DFT) and low-temperature scanning tunneling microscopy (STM) have been combined to examine the bonding of individual ${\mathrm{C}}_{60}$ molecules on Cu(111). Energy-resolved differential-conductance maps measured for adsorbed a Cu(111) surface by means STM, which are compared complemented theoretically computed spectral images. It has found that chemisorbs with six-membered ring parallel at two different binding sites constitute exclusive hexagonal sublattices. On...

We have combined first-principles and semiclassical Boltzmann transport theory to demonstrate the potential superb electronic thermal properties of bulk monolayer bismuth oxyiodide (BiOI). The exfoliation energy required produce BiOI (22.53 meV/Å2) is lower than that h-BN, implying possible manufacturing from bulk. calculated phonon frequencies, complemented with an ab initio molecular dynamic simulation for 8 ps at elevated temperature (900 K), reveal monolayer’s structural stability. band...

Recently, the bismuth oxybromide quintuple-layer (QL) was experimentally realized. In present study, we extensively examine stability, electronic and thermal transport of bulk (BiOBr) QL based on first-principles calculations semiclassical Boltzmann theory. We have found that BiOBr systems are dynamically thermally stable with an indirect band gap 2.86 3.08 eV, respectively. The emergence comparatively flat bands at top valence favours pronounced p-type Seebeck coefficient. Our calculated...

Two-dimensional Dirac materials have stimulated substantial research interest as binder-free anodes in metal-ion batteries, owing to their ultrahigh electronic conductivity, large specific area, and higher energy density. Here, using first-principles density functional theory calculations, we investigated the feasibility of monolayer TiC a potential anode material for Li/Na-ion batteries. The results indicate that exhibits excellent dynamical thermal stability. structure shows semimetallic...

The CNM (characterization of normal modes) method for extracting chemical information out vibrational spectra is tested molecules with relatively strong or weak coupling between internal modes. Symmetry, parameter set stability, and frequency uncertainty tests are applied to check whether modes, mode frequencies, amplitudes 𝒜nμ comply symmetry, independent the parameters ζn used describe molecular geometry fulfill a Lorentzian correlation differences Δωnμ=ωn−ωμ. In all cases considered,...

We have studied a wide range of transition metals to find potential carbon nanotube (CNT) catalysts for chemical vapor deposition (CVD) production.

Conformational changes caused by adsorption can dramatically affect a molecule's properties. Despite extensive study, however, the exact mechanisms underpinning conformational switching are often unclear. Here we show that conformation of prototypical flexible molecule, free-base tetra(4-bromophenyl) porphyrin, adsorbed on Cu(111), depends critically its precise site and that, remarkably, large dominated van der Waals interactions between molecule substrate surface. A combination scanning...

Despite the high theoretical specific energy in rechargeable sodium–sulfur batteries, shuttle effect severely hampers its capacity and reversibility, which could be overcome by introducing an anchoring material. We, herein, use first-principles calculations to study low-cost, easily synthesized, environmentally friendly, stable two-dimensional polar nitrogenated holey graphene (C2N) nonpolar polyaniline (C3N) investigate their performance as materials mechanism behind binding identify best...