The inherent quality of leaving groups in chemical reactions is related to their ionization potential and electron affinity using a quadratic model for the dependence energy on number electrons. A good group nucleophilic substitution/elimination one where difference between system with "optimum" electrons anion small. Similarly, electrophilic optimum cation This insight allows us define indices reactivity, which we term nucleofugality electrofugality, respectively. These are useful not only...

An efficient method for computing the quantum theory of atoms in molecules (QTAIM) topology electron density (or other scalar field) is presented. A modified Newton-Raphson algorithm was implemented finding critical points (CP) density. Bond paths were constructed with second-order Runge-Kutta method. Vectorization present makes it to scale linearly system size. The parallel efficiency decreases number processors (from 70% 50%) an average 54%. accuracy and performance are demonstrated by...

Abstract We introduce a method to compute atomic properties according the “quantum theory of atoms in molecules.” An integration grid real space is partitioned into subsets, ω i . The subset, , composed all points contained basin, Ω so that over reduced simple quadrature partition constructed from deMon2k's center grids by following steepest ascent path density starting each point grid. also technique exploits cellular nature make algorithm faster. performance tested computing and nonnuclear...

A new approach for computing the atom-in-molecule [quantum theory of atoms in molecule (QTAIM)] energies Kohn–Sham density-functional is presented and tested by QTAIM a set representative molecules. In approach, contribution correlation-kinetic energy (Tc) computed using virial relation. Based on our calculations, it shown that conventional where atomic are only noninteracting part kinetic might be error hundreds kJ/mol.

A new numerical integration procedure for exchange-correlation energies and potentials is proposed “proof of principle” results are presented. The grids built from sparse-tensor product (constructed according to Smolyak’s prescription [Dokl. Akad. Nauk. 4, 240 (1963)] ) on the unit cube. grid cube then transformed a over real space with respect weight function, which we choose be promolecular density. This produces “whole molecule” grid, in contrast conventional methods density-functional...

We present a molecular dynamics simulation of two-dimensional Carnot engine. The optimization this engine is achieved through the velocity piston, allowing not only power output but also some other figures merit involving entropy production. maximum and ecological efficiencies are computed. It shown that near ideal gas working substance displays an endoreversible Carnot-like behavior. This can be considered as prove validity model. An effective reversible cycle different than one obtained,...

We present a theoretical study on the role of van der Waals (vdW) interactions structure and, as consequence, photoinduced charge separation (CS) series dimer complexes formed by polymer P3HT and fullerene derivative PCBM. CS rate constants for P3HT/PCBM structures in which vdW are taken into account agree well with experimental data. Without proper treatment during geometry optimizations, predicted rates can be too low up to 3 orders magnitude. These variations computed not due changes...

The Quantum Theory of Atoms in Molecules (QTAIM) is used to elucidate the effects relativity on chemical systems. To do this, molecules are studied using density‐functional theory at both nonrelativistic level and scalar relativistic zeroth‐order regular approximation. Relativistic QTAIM properties topology electron density can be significant for systems with heavy atoms. It important, therefore, use appropriate treatment (Anderson Ayers, J. Phys. Chem. 2009, 115, 13001) when treating © 2016...

Measurement of early childhood development at the population level has traditionally been neglected in Latin America. In this context, Uruguay stands out for having two population-based protocols: Nutrition, Child Development and Health Survey (ENDIS), a home survey, School Readiness - Inventory (INDI). This paper aims to present both assessment experiences analyse Uruguayan children's cognitive socioemotional according sex their families' socioeconomic status (SES). Comparisons were made...

The topology of the molecular electron density benzene dithiol gold cluster complex Au4 -S-C6 H4 -S'-Au'4 changed when relativistic corrections were made and structure was close to a minimum Born-Oppenheimer energy surface. Specifically, new bond paths between hydrogen atoms on ring appeared, indicating that there is favorable interaction these at level. This consistent with observation becomes better acceptor are applied. In addition effects, here, we establish sensitivity basis sets...

We present a novel approach for performing multi-dimensional integration of arbitrary functions. The method starts with Smolyak-type sparse grids as cubature formulae on the unit cube and uses transformation coordinates based conditional distribution to adapt those real space. Our is tested integrals in one, two, three six dimensions. dimensional are used evaluate atomic interaction energies via Gordon–Kim model. conjunction nonlocal exchange-correlation energy functional proposed by Lee...

A study on static polarizabilities for a family of gold clusters (Aun, n = 6, 12, 20, 34, 54) is presented. For each cluster, density functional theory perturbation calculation was performed to compute the cluster polarizability and atom in using Bader´s “quantum atoms molecules” formalism. The tensor, $\mathord{\buildrel{\lower3pt\hbox{\scriptscriptstyle\leftrightarrow}}\over \alpha } _{\it cluster}$α↔cluster, expressed as sum atom-in-molecule tensors, cluster} \sum_\Omega...

Abstract We have recently reported that dispersion forces can drastic effects on the structure and charge separation in organic photovoltaics (OPVs) (Martinez et al., J. Phys. Chem. C 121, 20 134 [2017]). Here we investigate dimer complexes formed by polymer P3HT fullerene derivative PCBM. show how van der Waals (vdW) interactions affect geometrical structure, which has strong electronic UV‐Vis absorption spectrum. Time‐dependent density functional theory calculations demonstrate...

A high-octane number blend was obtained with Pt/WO₃–ZrO₂ catalysts, synthesized by an easy alkoxide-free method for the cluster size control.

Moment expansions for density functionals are revisited. This allows a simple proof of the equivalence between integrodifferential virial relation and coordinate-scaling equation. The is then used to show how, starting from an exact explicit form functional one system, may deduce other systems with same number electrons.

A differential evolution (DE) global optimization method for all-electron orbital-free density functional theory (OF-DFT) is presented. This does not need information about function derivatives to find extreme solutions. Results a series of known energy functionals are Ground state energies atoms (H Ar) obtained by direct minimization the without using either Lagrange multipliers or damping procedures reaching convergence. Our results in agreement with previous OF-DFT calculations standard...