Temperature‐dependent approach to chemical reactivity concepts in density functional theory

Abstract

The chemical reactivity concepts of density functional theory are studied through a unified view in the temperature‐dependent approach provided by the grand canonical ensemble. This procedure leads to a more general perspective that enriches our understanding of the behavior of the average energy and its derivatives with respect to the average number of electrons, provides alternative definitions for those quantities that are “ill defined” at zero temperature, and allows one to determine the relationships among reactivity concepts at any temperature. In particular, it has been found that at high temperatures the parabolic model for reactivity indicators may be justified through the electronic entropy term in the Helmholtz free energy, and that at nonzero temperatures there is an electronic heat capacity contribution to the average energy. In summary, the unified view of the temperature‐dependent approach is an important complement to the zero‐temperature formulation that clarifies fundamental issues therein.

Conceptual density functional theory based electronic structure principles

“…56 It is to be noted that in order to overcome the derivative discontinuity problem in the energy functional (E[N, v]), the incorporation of temperature within the denition of E [N, v] was considered by Franco-Perez, Ayers, Gázquez and Vela. [121][122][123] Within this approach, the premise of CDFT moves from the realm of canonical to a grand-canonical ensemble. [33][34][35][36][37][38][39] Within the premise of temperature dependent CDFT, the average electronic energy and its derivatives become the crucial component.…”

Molecular Models in Chemistry Education at University and Upper Secondary School - Structure of Amides

“…These outputs allow an accurate assessment of the acid-base properties of the model compounds in combination with approaches based on the qualitative theory of reactivity [11,12].…”

“…In order to illustrate pedagogical potential of molecular modelling by which the acid-base properties of the amides can easily be demonstrated, the following model series of compounds were proposed and analyzed [13,14] Computational models of these chemical compounds were geometrically optimized and then ESP on isodensity surface of electron density of 0.002 e/b 3 was calculated. The differences in acidity and basicity of the studied compounds were demonstrated semi-quantitatively on the basis of differences in the colour intensity of individual atoms in the molecular models and quantitatively by determination of the electrostatic potential (ESP) values on the nitrogen and hydrogen atoms in the amidic function [12]. In the model series: 1) ammonia, acetamide, acetimide the electrostatic potential on the nitrogen atom decreases from ammonia to acetimide.…”

A statistical thermodynamics view of electron density polarisation: application to chemical selectivity

“…The definition of pressure 5 and temperature [6][7][8] of an electron system and the proposal of a maximum entropy principle 9,10 are other examples. 11 More recently, temperaturedependent conceptual DFT descriptors [12][13][14][15][16] and temperaturedependent charge transfers have been paid a lot of attention, even though it has become quite clear that the temperatures required for tangible electron density modifications are much larger than the macroscopic temperatures used in routine experimental chemistry, ultimately suggesting that ''electronic'' and thermodynamic temperatures are two separate quantities.…”