MÁRQUEZ CRUZ , Antonio Marcial

La fotoquímica de los carbonilos de metales de transición y derivados es un campo en el que se ha venido desarrollando mucho trabajo en los últimos años. Las propiedades fotoquímicas de estos compuestos, conocidas prácticamente desde su descubrimiento, han conducido al desarrollo de multitud de estudios experimentales y teóricos destinados a...

A novel formulation of the Rys quadrature algorithm for the calculation of the electron repulsion integrals over Gaussian basis functions is presented. The new algorithm is specifically designed for high contractions. As for the original Rys quadrature algorithm, the new algorithm is very efficient for high angular momentum functions. In...

We report ab initio configuration interaction calculations on the optical transitions of the E′ center, a hole trapped at an oxygen vacancy, ( - O)3Si• +(O - )3, in silica. We found two competing excitation mechanisms: (1) promotion of one electron from an O(2p) valence band orbital to the singly occupied Si dangling bond; (2) charge transfer...

Ab initio self-consistent field and complete active space self-consistent field cluster-model wave functions have been obtained for a CO-Pt4 cluster model simulating the atop interaction of CO on Pt(111). The origin of the vibrational shift between free and chemisorbed CO has been investigated by means of the constrained space orbital variation...

Many transition-metal monoxides formally having an fcc rock-salt structure exhibit a relatively high degree of vacancies, in particular, the most stable structure of stoichiometric titanium monoxide corresponds to a monoclinic phase, α-TiO, showing 15% vacancies. The role of such vacancies on the stability of the solid has been the subject of...

We present in this work density functional theory calculations of the structural and electronic properties of (PbS)n nanoparticles with n=4-32. Particular care has been taken on the correct description of their electronic structure by using a hybrid functional including the spin-orbit coupling effects. We demonstrate that the bonding in PbS...

Density functional theory (DFT) based approaches within the local-density approximation or generalized gradient approximation frameworks fail to predict the correct electron localization in strongly correlated systems due to the lack of cancellation of the Coulomb self-interaction. This problem might be circumvented either by using hybrid...

The Pd/α-Al2O3(0001) interface at low Pd coverage has been studied by a variety of theoretical methods and models at this metal-oxide interface. All results are consistent and predict a noticeable interaction dominated by the metal polarization in response to the presence of the substrate. A significant contribution of the charge transfer from...

Because of the different components that constitute a quantum dots solar cells, QDSCs, and the difficulty of experimentally isolate the effect of each of them on the adsorption spectra of the system, we have modeled different Cu2S QDSCs models by means of DFT. A bottom-up approach can differentiate the effect of each component in the...

Dye-sensitized solar cells (DSSCs) have become in one important and promising technology in the photovoltaic field. The ability for a sensitizer to harvest light photons and inject the excited electrons into a photoanode, typically a metal oxide, determines the performance and operation range of the solar cell. Metal complexes with...

Chalcopyrite-structured semiconductors have promising potential as low-cost thermoelectric materials, but their thermoelectric figures of merit must be increased for practical applications. Understanding their thermal properties is important for engineering their thermal conductivities and achieving better thermoelectric behavior. We present...

Interfacial tension of some hydrocarbon/water systems, including a mixture of aliphatic and aromatic hydrocarbons, has been estimated on the basis of molecular dynamics simulations. The dependence of the interfacial properties on the salinity of the aqueous phase and the temperature has been simulated. Different concentrations in NaCl and CaCl2...

Ultrahigh-temperature ceramics (UHTCs) are a group of materials with high technological interest because of their applications in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from an experimental point of view, where only few laboratories...

Ministerio de Ciencia, Innovación y Universidades PID2019-106871GB-I00, TED2021-130874B-I00, PID2022-138063OB-I00

The optoelectronic properties of several Ag2S/graphene and FeS2/graphene nanostructures are examined through density functional theory calculations including dispersion forces. First, we analyzed the electronic structure of Ag2S and FeS2 nanocluster models, as prototypes of quantum dots, focusing on the electronic structure and absorption...

Ceria‐titania interfaces play a crucial role in different chemical processes but are especially promising for the photocatalytic splitting of water using light in the visible wavelength region when Pt is added to the system. However, the complexity of this hierarchical structure hampers the study of the origin of its outstanding properties. In...

In the last ten years, there has been an acceleration in the pace at which new catalysts for the watergas shift reaction are designed and synthesized. Pt-based catalysts remain the best solution when only activity is considered. However, cost, operation temperature, and deactivation phenomena are important variables when these catalysts are...

Experimental catalytic activity measurements, Diffuse Reflectance Infrared Fourier Spectroscopy, and Density Functional Theory calculations are used to investigate the role and dynamics of surface oxygen vacancies in the CO oxidation with O2 catalyzed by Au nanoparticles supported on a Y-doped TiO2 catalyst. Catalytic activity measurements...

A series of titanium oxide catalysts modified with yttrium has been prepared by sol¿gel method and their structural properties have been studied. The incorporation of yttrium in the titania lattice favors the formation of oxygen vacancies while at low Y loadings the anatase structure is preserved. The catalytic activity of these solids for CO...

The catalytic and structural properties of five different nanoparticle catalysts with varying Au/Ni composition were studied by six different methods, including in situ X-ray absorption spectroscopy and density functional theory (DFT) calculations. The as-prepared materials contained substantial amounts of residual capping agent arising from...

The aim of this work was to investigate the influence of the incorporation of substituents at the end of the hydrophobic tail on the binding of cationic surfactants to α-, β-, and -cyclodextrins. The equilibrium binding constants of the 1:1 inclusion complexes formed follow the trend K1(α-CD)>K1(β-CD)>>K1(-CD), which can be explained by...