Browsing by Author "1eeb42ea455441a5ba99a958f8dfc704"
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An explicit approach to conceptual density functional theory descriptors of arbitrary order
Heidar Zadeh, Farnaz; Richer, Michael; Fias, Stijn; Miranda Quintana, Ramón; Chan, Matthew; Franco Pérez, Marco; González Espinoza, Cristina; Kim, Taewon; Lanssens, Caitlin; Patel, Anand; Yang, Xiaotian; Vöhringer Martinez, Esteban; Cárdenas Valencia, Carlos; Verstraelen, Toon; Ayers, Paul W. (Elsevier, 2016)We present explicit formulas for arbitraryorder derivatives of the energy, grand potential, electron density, and higherorder response functions with respect to the number of electrons, and the chemical potential for any ... 
An informationtheoretic resolution of the ambiguity in the local hardness
Heidar Zadeh, Farnaz; Fuentealba Rosas, Patricio; Cárdenas, Carlos; Ayers, Paul W. (2014)The ambiguity of the local hardness is resolved by using information theory to select definitions of the local hardness that are as close as possible to a welldefined approximate formula for the local hardness. A condensed ... 
Atomic Charges and the Electrostatic Potential Are IllDefined in Degenerate Ground States
Bultinck, Patrick; Cárdenas Valencia, Carlos; Fuentealba Rosas, Patricio; Johnson, Paul A.; Ayers, Paul W. (American Chemical Society, 2013)A system in a spatially degenerate ground state responds in a qualitatively different way to positive and negative point charges. This means that the molecular electrostatic potential is illdefined for degenerate ... 
Benchmark values of chemical potential and chemical hardness for atoms and atomic ions (including unstable anions) from the energies of isoelectronic series
Cardenas, Carlos; Heidar Zadeh, Farnaz; Ayers, Paul W. (2016)We present benchmark values for the electronic chemical potential and chemical hardness from reference data for ionization potentials and electron affinities. In cases where the energies needed to compute these quantities ... 
Chemical reactivity descriptors for ambiphilic reagents: Dual descriptor, local hypersoftness, and electrostatic potential
Cárdenas, Carlos; Rabi, Nataly; Ayers, Paul W.; Morell, Christophe; Jaramillo, Paula; Fuentealba Rosas, Patricio (2009)The secondorder response of the electron density with respect to changes in electron number, known as the dual descriptor, has been established as a key reactivity indicator for reactions like pericyclic reactions, where ... 
Densityfunctional theory with additional basic variables: Extended Legendre transform
Ayers, Paul W.; Fuentealba Rosas, Patricio (2009)In a recent series of papers, Higuchi and Higuchi defined an extended constrainedsearch procedure by extending the Levy constrained search by adding additional constraints. As shown here, this procedure can be equivalently ... 
How reliable is the hardsoft acidbase principle? An assessment from numerical simulations of electron transfer energies
Cárdenas, Carlos; Ayers, Paul W. (2013)By computing the electrontransfer energies for two million simulated double acidbase exchange reactions, we assess the reliability of the global hardsoft acidbase (HSAB) principle. We find that the HSAB principle is ... 
How to Compute the Fukui Matrix and Function for Systems with (Quasi)Degenerate States
Bultinck, Patrick; Cárdenas Valencia, Carlos; Fuentealba Rosas, Patricio; Johnson, Paul A.; Ayers, Paul W. (American Chemical Society, 2014)A system in a spatially (quasi)degenerate ground state responds in a qualitatively different way to a change in the external potential. Consequently, the usual method for computing the Fukui function, namely, taking ... 
How to Compute the Fukui Matrix and Function for Systems with (Quasi)Degenerate States
Bultinck, Patrick; Cárdenas Valencia, Carlos; Fuentealba Rosas, Patricio; Johnson, Paul A.; Ayers, Paul W. (ACS, 2013)A system in a spatially (quasi)degenerate ground state responds in a qualitatively different way to a change in the external potential. Consequently, the usual method for computing the Fukui function, namely, taking ... 
In pursuit of negative Fukui functions: examples where the highest occupied molecular orbital fails to dominate the chemical reactivity
Echegaray, Eleonora; Cárdenas Valencia, Carlos; Rabi, Sandra; Rabi, Nataly; Lee, Sungmin; Zadeh, Farnaz Heidar; Toro Labbe, Alejandro; Anderson, James S.; Ayers, Paul W. (Springer, 2013)In our quest to explore molecules with chemically significant regions where the Fukui function is negative, we explored reactions where the frontier orbital that indicates the sites for electrophilic attack is not the ... 
In pursuit of negative Fukui functions: Molecules with very small band gaps
Echegaray, Eleonora; Rabi, Sandra; Cárdenas, Carlos; Zadeh, Farnaz Heidar; Rabi, Nataly; Lee, Sungmin; Anderson, James S.; Toro Labbé, Alejandro; Ayers, Paul W. (Springer Verlag, 2014)A justification for the likely presence of negative Fukui functions in molecules with small band gaps is given, and a computational study performed to check whether molecules with small band gaps have negative Fukui functions ... 
Insights into the mechanism of an S N2 reaction from the reaction force and the reaction electronic flux
Giri, Santanab; Echegaray, Eleonora; Ayers, Paul W.; Núñez Vásquez, Álvaro; Lund Plantat, Fernando; Toro Labbé, Alejandro (2012)The mechanism of a simple S N2 reaction, viz; OH  + CH 3F = CH 3OH + F  has been studied within the framework of reaction force and reaction electronic flux. We have computationally investigated three different types of ... 
Quantitative electrophilicity measures
González Martínez, Marco; Cárdenas Valencia, Carlos; Rodríguez, Juan, I; Liu, Shubin; Heidar Zadeh, Farnaz; Miranda Quintana, Ramon Alain; Ayers, Paul W. (Peking University Press, 2018)Quantitative correlation of several theoretical electrophilicity measures over different families of organic compounds are examined relative to the experimental values of Mayr et al. Notably, the ability to predict these ... 
Should negative electron affinities be used for evaluating the chemical hardness?
Cárdenas, Carlos; Ayers, Paul; De Proft, Frank; Tozer, David J.; Geerlings, Paul (2011)Despite recent advances in computing negative electron affinities using densityfunctional theory, it is an open issue as to whether it is appropriate to use negative electron affinities, instead of zero electron affinity, ... 
Symmetric nonlocal weighted density approximations from the exchangecorrelation hole of the uniform electron gas
CuevasSaavedra, Rogelio; Chakraborty, Debajit; Rabi, Sandra; Cárdenas, Carlos; Ayers, Paul W. (2012)Nonlocal exchangecorrelation energy functionals are constructed using the accurate model exchangecorrelation hole for the uniform electron gas developed by GoriGiorgi and Perdew. The exchangecorrelation hole is constrained ... 
The Fukui Potential and the Capacity of Charge and the Global Hardness of Atoms
Cárdenas Valencia, Carlos; Tiznado Vásquez, William; Ayers, Paul W.; Fuentealba Rosas, Patricio (AMER CHEMICAL SOC, 20110225)In the course of a reaction it is the shape of the Fukui potential that guides a distant reagent toward the site where an electrophile/nucleophile is willing to accept/ donate charge. In this paper we explore the ... 
The HSAB principle from a finite temperature grand‑canonical perspective
Miranda Quintana, Ramón; Kim, Taewon David; Cárdenas Valencia, Carlos; Ayers, Paul W. (Springer, 2017)We provide a new proof for Pearson’s hard/ soft acid/base (HSAB) principle. Unlike alternative proofs, we do not presuppose a simplified parabolic dependence on the energy of the system with respect to changes in ... 
The HSAB principle from a finitetemperature grandcanonical perspective
MirandaQuintana, Ramón Alain; Kim, Taewon David; Cárdenas, Carlos; Ayers, Paul W. (Springer New York LLC, 2017)© 2017, SpringerVerlag GmbH Germany.We provide a new proof for Pearson’s hard/soft acid/base (HSAB) principle. Unlike alternative proofs, we do not presuppose a simplified parabolic dependence on the energy of the system ... 
Understanding chemical reactivity in extended systems: exploring models of chemical softness in carbon nanotubes
Cárdenas Valencia, Carlos; Muñoz, Macarena; Contreras, Julia; Ayers, Paul W.; Gomez, Tatiana; Fuentealba Rosas, Patricio (Peking University Press, 2018)Chemical reactivity towards electron transfer is captured by the Fukui function. However, this is not well defined when the system or its ions have degenerate or pseudodegenerate ground states. In such a case, the firstorder ...