Search results for "DF"
showing 10 items of 1699 documents
The effect of the fused-ring substituent on anthracene chalcones: crystal structural and DFT studies of 1-(anthracen-9-yl)-3-(naphthalen-2-yl)prop-2-…
2018
Two new anthracene chalcones, namely 1-(anthracen-9-yl)-3-(naphthalen-2-yl)prop-2-en-1-one and 1-(anthracen-9-yl)-3-(pyren-1-yl)prop-2-en-1-one, have been successfully synthesized and the effect of the different fused ring substituent system attached to the anthracene chalcone derivative investigated. These compounds show a very narrow band gap due to the large p-conjugated systems, making them promising candidates as optoelectronic materials. Hirshfeld surface analysis has been carried out to show the contribution of intermolecular contacts and weak interactions to supramolecular stabilization.
Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity.
2016
Indexación: Web of Science Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic and nucleophilic Parr functions, as the most relevant indices for the study of organic reactivity, are discussed. http://www.mdpi.com/1420-3049/21/6/748
Setting the photoelectron clock through molecular alignment
2020
The interaction of strong laser fields with matter intrinsically provides a powerful tool for imaging transient dynamics with an extremely high spatiotemporal resolution. Here, we study strong-field ionisation of laser-aligned molecules, and show a full real-time picture of the photoelectron dynamics in the combined action of the laser field and the molecular interaction. We demonstrate that the molecule has a dramatic impact on the overall strong-field dynamics: it sets the clock for the emission of electrons with a given rescattering kinetic energy. This result represents a benchmark for the seminal statements of molecular-frame strong-field physics and has strong impact on the interpreta…
Eliminating Artificial Boundary Conditions in Time-Dependent Density Functional Theory Using Fourier Contour Deformation
2023
We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain, FCD yields a high-order accurate numerical solution of the time-dependent Schrödinger equation directly in free space, without the need for artificial boundary conditions. Of the many existing artificial boundary condition schemes, FCD is most similar to an exact nonlocal transparent boundary condition, but it works directly on Cartesian grids in any dimension, and runs on top of the fast Fourier transform rather than fast algorithms for the application of …
Spectroscopic signatures of the carbon buckyonions C60@C180 and C60@C240: a dispersion-corrected DFT study
2013
We have investigated, using dispersion corrected DFT methods, the structure and the spectroscopic properties of carbon buckyonions C-60@C-180 and C-60@C-240. C-60, C-180 and C-240 showed a noticeable variation of their geometries in C-60@C-180 and C-60@C-240, upon encapsulation. Inclusion of the dispersion correction term in the calculations has a significant effect on the geometry. C-60@C-180 has a large positive interaction energy, while for C-60@C-240 a negative value is found indicating that only C-240 can easily accommodate C-60. In both cases dispersion interactions strongly contribute to the stabilization of the complexes. Vibrational frequencies, electronic transitions and NMR prope…
Adsorbed CO on group 10 metal fragments: A DFT study
2009
DFT calculations on the helicopter and cartwheel rotations of one CO molecule adsorbed at the bridge site on metal-surface fragments, characterized by two (M(8)) or three (M(14)) metal-atom layers (M = Ni, Pd, Pt) were performed by the B3LYP[LANL2DZ+6-31 g(d,p)] method, to rationalize the adsorption energetics and the steric hindrance characteristics of surface CO molecules. Potential Energy Surfaces were obtained, either fixing the C-O bond-length or allowing it to change. The behavior of the three metals, as obtained from the study of the configurational space characterizing the CO adsorption on the fragments was explained on the basis of the interaction energies involved in the different…
Understanding the local reactivity in polar organic reactions through electrophilic and nucleophilic Parr functions
2013
[EN] Building upon our recent studies devoted to the bonding changes in polar reactions [RSC Advances, 2012, 2, 1334 and Org. Biomol. Chem., 2012, 10, 3841], we propose herein two new electrophilic, P-k(+), and nucleophilic, P-k(-), Parr functions based on the spin density distribution at the radical anion and at the radical cation of a neutral molecule. These local functions allow for the characterisation of the most electrophilic and nucleophilic centres of molecules, and for the establishment of the regio- and chemoselectivity in polar reactions. The proposed Parr functions are compared with both, the Parr-Yang Fukui functions [J. Am. Chem. Soc. 1984, 106, 4049] based on frontier molecul…
Computational Study on Cesium Azide Trapped in a Cyclopeptidic Tubular Structure
2008
The structures and the electronic properties of host-guest complexes formed by a cyclopeptidic tubular aggregate and the species CsN3, CS2(N-3)(2), and CS2N6 have been investigated by means of density functional theory. Taking advantage of the azide property to act as a bridge ligand between two or more metal cations, it may be possible to trap N-3(-) ions inside a confined space. This could be important for the preparation of polynitrogen molecules N-n. Results show that there are significant attractive interactions between the azide ion and the cavity walls, which make the ion stay inside the inner empty space of the cyclopeptidic aggregate. The confinement of the species CS2(N-3)(2) forc…
Molecular Features Behind Formation of α or β Co-Crystalline and Nanoporous-Crystalline Phases of PPO
2022
Guest molecular features determining the formation of α and β phases of poly(2-6-dimethyl-1,4-phenylene) oxide (PPO) are explored by collecting literature data and adding many new film preparations, both by solution casting and by guest sorption in amorphous films. Independently of the considered preparation method, the α-form is favored by the hydrophobic and bulky guest molecules, while the hydrophilic and small guest molecules favor the β-form. Furthermore, molecular modeling studies indicate that the β-form inducer guests establish stronger dispersive interactions with the PPO units than the α-form inducer guests. Thus, the achievement of co-crystalline (and derived nanoporous crystalli…
Form factors of the isovector scalar current and the ηπ scattering phase shifts
2015
33 pages.- 14 figures.- v2: Some clarifications and corrections of typos