Examinando por Autor "Cardenas, Carlos"

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    Ítem
    Cluster Assembled Silicon-Lithium Nanostructures: A Nanowire Confined Inside a Carbon Nanotube
    (Frontiers Media S.A., 2021-11) Orellana, Walter; Pino-Rios, Ricardo; Yañez, Osvaldo; Vásquez Espinal, Alejandro; Peccati, Francesca; Contreras García, Julia; Cardenas, Carlos; Tiznado, William
    We computationally explore an alternative to stabilize one-dimensional (1D) silicon-lithium nanowires (NWs). The Li12Si9 Zintl phase exhibits the NW (Formula presented.), combined with Y-shaped Si4 structures. Interestingly, this NW could be assembled from the stacking of the Li6Si5 aromatic cluster. The (Formula presented.) @CNT nanocomposite has been investigated with density functional theory (DFT), including molecular dynamics simulations and electronic structure calculations. We found that van der Waals interaction between Li’s and CNT’s walls is relevant for stabilizing this hybrid nanocomposite. This work suggests that nanostructured confinement (within CNTs) may be an alternative to stabilize this free NW, cleaning its properties regarding Li12Si9 solid phase, i.e., metallic character, concerning the perturbation provided by their environment in the Li12Si7 compound. Copyright © 2021 Orellana, Pino-Rios, Yañez, Vásquez-Espinal, Peccati, Contreras-García, Cardenas and Tiznado.
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    Kick-Fukui: A Fukui Function-Guided Method for Molecular Structure Prediction
    (American Chemical Society, 2021-08-23) Yañez, Osvaldo; Báez-Grez, Rodrigo; Inostroza, Diego; Pino-Rios, Ricardo; Rabanal-León, Walter A.; Contreras-García, Julia; Cardenas, Carlos; Tiznado, William
    Here, we introduce a hybrid method, named Kick-Fukui, to explore the potential energy surface (PES) of clusters and molecules using the Coulombic integral between the Fukui functions in the first screening of the best individuals. In the process, small stable molecules or clusters whose combination has the stoichiometry of the explored species are used as assembly units. First, a small set of candidates has been selected from a large and stochastically generated (Kick) population according to the maximum value of the Coulombic integral between the Fukui functions of both fragments. Subsequently, these few candidates are optimized using a gradient method and density functional theory (DFT) calculations. The performance of the program has been evaluated to explore the PES of various systems, including atomic and molecular clusters. In most cases studied, the global minimum (GM) has been identified with a low computational cost. The strategy does not allow to identify the GM of some silicon clusters; however, it predicts local minima very close in energy to the GM that could be used as the initial population of evolutionary algorithms. ©