The reactivity of Pd4, Pt4, Cu4, Ag4, and Au4 clusters supported on TiC(001) toward molecular hydrogen dissociation has been studied by means density functional based theory periodic models compared to that the (111) (001) surfaces. Pd4 Pt4 interact rather strongly with substrate, but interaction Pd4/TiC Pt4/TiC systems is also very strong. As a consequence substantial admetal↔carbide interactions, adsorbed H2 molecule becomes more difficult dissociate than corresponding extended Here,...

In the first paper of this series, authors derived an expression for interaction energy between two reagents in terms chemical reactivity indicators that can be from density functional perturbation theory. While negative energies explain reactivity, is often more simply explained using "|dμ| big good" rule or maximum hardness principle. Expressions change potential (μ) and when interact are derived. A partial justification principle appear reappear hardness, but with opposite sign.

Using perturbation theory within the framework of conceptual density functional theory, we derive a lower bound for lattice energy ionic solids. The main element is Fukui potential in nuclei molecule corresponding to unit formula solid. Thus, propose model calculate terms potential. Our method, which extremely simple, performs well as other methods using crystal structure information alkali halide method proposed here correlates surprisingly with experimental data on diverse series solids...

We have carried out a theoretical study of the geometrical and electronic structures family planar dimers constituted by zinc(II) pyrazinoporphyrazine phthalocyanine with peripheral electron-donating electron-withdrawing substituents R [where = -OH (1), -C(CH(3))(3) (2), -CH(3) (3), -C(6)H(5) (4), -H (5), -CO(2)H (7), -NO(2) -PO(3)H(2) (8)]. The complexes are connected varying bridge (B) ligand, where, in 1-9, B is -CH= and, 10-12, -N=, -O-, -S-, respectively. group was included identified...

Low-density polyethylene composites containing different sizes of calcium oxide (CaO) nanoparticles were obtained by melt mixing. The CaO synthesized either the sol-gel or sonication methods, obtaining two sizes: ca. 55 nm and 25 nm. These used as-synthesized modified organically on surface with oleic acid (Mod-CaO), at concentrations 3, 5, 10 wt% in polymer. Mod-CaO can act as nucleating agents, increasing polymer’s crystallinity. Young’s Modulus increased nanoparticles, rendering higher...

Fukui functions (FFs) are chemical descriptors that useful to explain the reactivity of systems toward electron transfer. Whereas they have been widely employed for molecules, their application extended is scarce. One reasons limited development such analysis in solids improper evaluation FFs usual computational approaches based on density functional theory and periodic boundary conditions. In this work we compare available propose a new method interpolation partially charged mitigates some...

The Fukui function and its associated potential serve as essential descriptors of chemical reactivity within the framework conceptual density functional theory (c-DFT). While c-DFT is well-established for molecular systems, it encounters formal technical challenges when applied to extended systems. This comprehensive study addresses complexities involved in calculating systems with periodic boundary conditions (PBC). We specifically investigate introduction a fictitious compensating...

Density functional calculations carried out for realistic models evidence that Au particles supported on TiC(001) are very active towards H2 dissociation. The molecular mechanisms show the support is not a mere spectator but plays major role in catalyzed reaction and acts as reservoir of atomic H, making this system an excellent candidate catalyst hydrogenation olefins hydrodesulfurization reactions.

Reactivity descriptors indicate where a reagent is most reactive and how it likely to react. However, reaction will only occur when the encounters suitable partner. Determining whether pair of reagents well-matched requires developing reactivity rules that depend on both reagents. This can be achieved using expression for minimum-interaction-energy obtained from density functional theory. Different terms in this dominant different circumstances; depending which control reactivity, indicators...

A systematic density functional study of the adsorption and dissociation H2 on clean (001) surface various transition metal carbides (TMCs; TM = Ti, Zr, V, Mo) Au4 nanoclusters supported these TMCs is presented. It found that bare strongly depends chemical nature support. Thus, molecule interacts rather with TiC(001) ZrC(001) but very weakly VC(001) δ-MoC(001). For cluster, two different types molecular mechanisms are found. Au4/TiC(001) Au4/ZrC(001), leads to a H atom directly interacting...

In this work, we adopt a quantum mechanical approach based on time-dependent density functional theory (TDDFT) to study the optical and electronic properties of alizarin supported TiO2 nano-crystallites, as prototypical dye-sensitized solar cell. To ensure proper alignment donor (alizarin) acceptor (TiO2 nano-crystallite) levels, static excitation spectra are simulated using in response. The ultrafast photoelectron transfer from dye cluster is an explicitly time-dependent, one-electron TDDFT...

The interaction of atoms Groups 9, 10, and 11 with the (001) surface TiC, ZrC, VC, δ-MoC has been studied by means periodic density functional calculations using slab models. calculated values adsorption energy are rather large, especially for 9 10 elements (Eads = 3−6 eV), but without clear trends along series. Nevertheless, analysis at different sites indicates that adsorbed will be relatively mobile. Many admetals electronically perturbed upon carbide surfaces. Co, Ni, Cu, Rh adatoms get...

The physical characterization of the chemical bond in ground state has been a central theme to theoretical chemistry. Among many techniques, quantum topology (QCT) emerged as robust technique understand features and electron organization within molecules. One consolidate tool QCT is topological analysis localization function (ELF). Most research on ELF focused either singlet states or first excited triplet. However, most photochemical reactions photophysical processes occur with same...

The possibility of dye charge recombination in DSSCs remains a challenge for the field. This consists of: (a) back-transfer from TiO2 to oxidized and (b) intermolecular electron transfer between dyes. latter is attributed aggregation due dimeric conformations. leads poor injection which decreases photocurrent conversion efficiency. Most organic sensitizers are characterized by an Acceptor-Bridge-Donor (A-Bridge-D) arrangement that commonly employed provide separation and, therefore, lowering...

Abstract This paper presents a brief summary of the difficulty that resides in definition elusive concept local chemical hardness. We argue hardness should be useful to reactivity principle and not just as mere definition. then continue with formal discussion about benefits difficulties using Fukui potential, which is interpreted an alchemical derivative (alchemical hardness), descriptor molecules. Computational evidence shows at least good combination other two well‐stabilized descriptors...

Gold–graphene interaction at the interface is evaluated through different polyaromatic hydrocarbons (PAH), accounted by C6H6, C24H12, C54H16, and C96H18, focusing into energetic terms related to overall interaction. Our results characterize neutral gold–PAH nature with 45% of dispersion character, 35% electrostatic, 20% covalent suggesting that moderate van der Waals character mostly involved in interaction, which increases according size respective PAH. The resulting surface charge...

Since its first definition, back in 1990, the electron localization function (ELF) has settled as one of most commonly employed techniques to characterize nature chemical bond real space. Although work using ELF focused on study ground-state reactivity, a growing interest blossomed apply these nearly unexplored realm excited states and photochemistry. accurate electronic usually require account appropriately for correlation, standard single-determinant formulation cannot be blindly applied...

The high solar-to-electric-power conversion efficiency reported for 5-(4-carboxylphenyl)-10,15,20-tetrakis (2,4,6-trimethylphenyl) porphyrinatozinc(II) (TPP-Zn(II)) prompted us to study at a molecular level the interaction of this dye on rutile surface. –COOH group was included in complex anchor onto semiconductor oxide. Three main modes adsorption anchoring oxide surface were studied, and vibrational analysis carried out characterize it as either minimum energy or transition state...

Abstract Low‐density polyethylene (LDPE) nanocomposites containing magnesium oxide (MgO) nanoparticles are obtained by melt mixing. MgO ca. 29 ± 2 nm synthesized sol–gel and organically modified on the surface with oleic acid (Mod‐MgO), whose final concentration in polymers is 3, 5, 10 wt%. The presence of these did not affect crystallization process LDPE. However, Young's modulus increases wt% Mod‐MgO nanoparticles, rendering higher reinforcement effects an increase as high 48%. This...