Search results for "functional"
showing 10 items of 4822 documents
Kohn-Sham Decomposition in Real-Time Time-Dependent Density-Functional Theory An Efficient Tool for Analyzing Plasmonic Excitations
2017
The real-time-propagation formulation of time-dependent density-functional theory (RT-TDDFT) is an efficient method for modeling the optical response of molecules and nanoparticles. Compared to the widely adopted linear-response TDDFT approaches based on, e.g., the Casida equations, RT-TDDFT appears, however, lacking efficient analysis methods. This applies in particular to a decomposition of the response in the basis of the underlying single-electron states. In this work, we overcome this limitation by developing an analysis method for obtaining the Kohn-Sham electron-hole decomposition in RT-TDDFT. We demonstrate the equivalence between the developed method and the Casida approach by a be…
Self-Consistent Charge Density-Functional Tight-Binding Parametrization for Pt–Ru Alloys
2017
We present a self-consistent charge density-functional tight-binding (SCC-DFTB) parametrization for PtRu alloys, which is developed by employing a training set of alloy cluster energies and forces obtained from Kohn-Sham density-functional theory (DFT) calculations. Extensive simulations of a testing set of PtRu alloy nanoclusters show that this SCC-DFTB scheme is capable of capturing cluster formation energies with high accuracy relative to DFT calculations. The new SCC-DFTB parametrization is employed within a genetic algorithm to search for global minima of PtRu clusters in the range of 13-81 atoms and the emergence of Ru-core/Pt-shell structures at intermediate alloy compositions, consi…
A Self-Consistent Charge Density-Functional Tight-Binding Parameterization for Pt-Ru Alloys
2017
We present a self-consistent charge density-functional tight-binding (SCC-DFTB) parametrization for PtRu alloys, which is developed by employing a training set of alloy cluster energies and forces obtained from Kohn–Sham density-functional theory (DFT) calculations. Extensive simulations of a testing set of PtRu alloy nanoclusters show that this SCC-DFTB scheme is capable of capturing cluster formation energies with high accuracy relative to DFT calculations. The new SCC-DFTB parametrization is employed within a genetic algorithm to search for global minima of PtRu clusters in the range of 13–81 atoms and the emergence of Ru-core/Pt-shell structures at intermediate alloy compositions, consi…
The role of polaronic states in the enhancement of CO oxidation by single-atom Pt/CeO2
2023
Single Atom Catalysts (SACs) have shown that the miniaturization of the active site implies new phenomena like dynamic charge transfer between isolated metal atoms and the oxide. To obtain direct proof of this character is challenging, as many experimental techniques provide averaged properties or have limitations with poorly conductive materials, leaving kinetic measurements from catalytic testing as the only reliable reference. Here we present an integrated Density Functional Theory-Microkinetic model including ground and metastable states to address the reactivity of Pt1/CeO2 for CO oxidation. Our results agree with experimentally available kinetic data in the literature and show that CO…
Reaction Mechanism of an Intramolecular Oxime Transfer Reaction: A Computational Study
2014
Density functional theory (PBE0/def2-TZVPP) calculations in conjunction with a polarizable continuum model were used to assess the mechanism of the intramolecular oxime transfer reaction that leads to the formation of isoxazolines. Different diastereomers of the intermediates as well as different oximes (formaldehyde and acetone oxime) were considered. The computed reaction profile predicts the water-addition and -expulsion steps as the highest barriers along the pathway, a conclusion that is in line with the experimental evidence obtained previously for these reactions. peerReviewed
Data from: The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agro-ecosystem services acros…
2019
[Usage Notes] Martin et al_2019_datatables Data used in Martin et al. (2019) compiled from 49 studies and 1,515 landscapes across Europe. Includes data on the abundance of arthropod species per site and data on pollination, natural pest control and yields in crops across Europe. Martin et al_2019_data tables_300319.xlsx Martin et al_2019_traits database Functional traits data for 2088 species (morphospecies, individuals) from 144 arthropod families sampled in agricultural landscapes across Europe. All traits are categorical and based on published literature or expert knowledge. They are described in Table 1 and Appendix S1 of Martin et al. (2019). The traits included are: feeding habit ('Fu…
Some remarks on Hilbert's (Weak) Nullstellensatz
2011
Certain remarks are provided related to weak nullstellensatz exploiting some problems proposed in Fulton’s book entitled “An Introduction to Algebraic Geometry” and elementary notions of Functional Analysis.
Acoustic, neural, and perceptual correlates of polyphonic timbre
2012
Freeze dried pomegranate juices of Moroccan fruits: main representative phenolic compounds.
2022
The pomegranate (Punica granatum) is an ancient perennial plant species of the Punicaceae family. Its seeds are consumed as food or as juice. Previous studies have noted that pomegranate juice encompasses many active compounds with beneficial effects. The main goals of this work were to study the phenolic components of freeze-dried and reconstituted pomegranate juices obtained from 13 pomegranate genotypes growing in Morocco.We analyzed several pomegranate juices using high-performance liquid chromatography and high-resolution mass spectrometry to determine phenolic compounds. Twenty-seven bio-phenols, belonging to four different classes (phenolic acids, hydrolyzable tannins, anthocyanins, …