Post-Franco Theatre

In the multiple realms and layers that comprise the contemporary Spanish theatrical landscape, “crisis” would seem to be the word that most often lingers in the air, as though it were a common mantra, ready to roll off the tongue of so many theatre professionals with such enormous ease, and even enthusiasm, that one is prompted to wonder whether it might indeed be a miracle that the contemporary technological revolution – coupled with perpetual quandaries concerning public and private funding for the arts – had not by now brought an end to the evolution of the oldest of live arts, or, at the very least, an end to drama as we know it

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Basis set superposition error in atomic cluster calculations

In this work, the basis set superposition error (BSSE) has been analyzed for the systems Cu2, Cu3, Cu6 and Cu13 as prototypes of metallic clusters. Various basis sets have been tested. In addition, pseudopotentials of 1- and 19-valence electrons have also been studied in relationship to the BSSE. The results are conclusive. At the present, it is almost impossible to do an all-electron calculation in transition-metal clusters without great error in basis set superposition, even for clusters of moderate size. The only solution seems to be using pseudopotentials with a carefully chosen basis set

On the density functional relationship between static dipole polarizability and global softness

The relationship between global softness and static dipole polarizability is explored from the analogy of the spherical averages defined within density functional theory. A cubic relationship is obtained that is consistent with the experimental observation for atoms. The relationship is found to hold reasonably well for similarly bonded molecules

Static dipole polarizabilities through density functional methods

Various density functionals have been tested in calculating atomic and molecular dipole polarizabilities. For atoms, it has been found that the results are not competitive with more sophisticated ab initio methods. Exchange and correlation effects have been analyzed separately to show that the main cause of errors lies in the exchange functional models. Strong numerical evidence is given to support the idea that a right asymptotic behavior of the exchange potential is essential to obtain reliable values for the dipole polarizabilities. In this sense, the hybrid method proposed by Becke (J. Chem. Phys. 1993, 98, 5648) and the phenomenological exchange potential proposed by van Leeuwen and Baerends (Phys. Rev. 1994, A49, 2421), performed much better. For molecules, the comparison is more difficult because of the scarcity of reliable experimental values as well as ab initio calculations including correlation effects. The results have however shown that the bonding effects predominate ove

On the location of the electron lone pair of XeF6 and related molecules

Theoretical results based on the use of the electron localization function confirmed, for the first time, the predictions of the valence shell electron pair repulsion model about the electron lone pair on the XeF6 and related molecules. © 2003 Elsevier B.V. All rights reserved

Molecular electronic excitations and the minimum polarizability principle

The validity of the minimum polarizability principle upon electronic excitation is studied as a companion principle of that obtained by Chattaraj and Poddar in the case of the maximum hardness principle. Twelve diatomic molecules have been selected and, both the hardness and the dipole polarizability for the ground and excited states have been calculated by means of ab initio density functional calculations using Sadlej's basis set. It has been found that a molecule is less polarizable in its ground state than in an electronically excited state of the same spin multiplicity

Empirical energy - Density relationships for the analysis of substituent effects in chemical reactivity

Electronic substituent effects may be rationalized in terms of Hammett- like linear relationships between global energy-dependent quantities and local electronic descriptors of reactivity. These linear relationships are framed on a local hard and soft acids and bases (HSAB) principle in accord with previous results reported by Li and Evans [J. Am. Chem. Soc. 1995, 117, 7756]. Chemical substitution is indirectly assessed as local responses at the active center of the substrate, with the Fukui function and local softness as the key quantities within the present approach. This model of chemical substitution has a potential advantage with respect to models based on group properties using the electronegativity equalization principle (EEP), since the transferability of group properties is not required. The formalism is illustrated for the gas-phase basicity of alkylamines, and the gas-phase acidity of alkyl alcohols and alkyl thioalcohols. Our results based on the local HSAB rule agree wel