Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective

Several applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradien...

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Main Author: Roman F. Nalewajski
Format: Article
Language:English
Published: MDPI AG 2019-03-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/9/6/1262
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spelling doaj-21e6c9ae901a4fe0a3f04da1eb67d4242020-11-24T20:54:35ZengMDPI AGApplied Sciences2076-34172019-03-0196126210.3390/app9061262app9061262Understanding Electronic Structure and Chemical Reactivity: Quantum-Information PerspectiveRoman F. Nalewajski0Department of Theoretical Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, PolandSeveral applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradient information. Continuities of molecular probability and current distributions, reflecting the modulus and phase components of molecular wavefunctions, respectively, are summarized. Resultant measures of the entropy/information descriptors of electronic states, combining the classical (probability) and nonclassical (phase/current) contributions, are introduced, and information production in quantum states is shown to be of a nonclassical origin. Importance of resultant information descriptors for distinguishing the bonded (entangled) and nonbonded (disentangled) states of reactants in acid(A)–base(B) systems is stressed and generalized entropy concepts are used to determine the phase equilibria in molecular systems. The grand-canonical principles for the minima of electronic energy and overall gradient information allow one to explore relations between energetic and information criteria of chemical reactivity in open molecules. The populational derivatives of electronic energy and resultant gradient information give identical predictions of electronic flows between reactants. The role of electronic kinetic energy (resultant gradient information) in chemical-bond formation is examined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and changes of the overall structure information in chemical processes are addressed. The frontier-electron basis of the hard (soft) acids and bases (HSAB) principle is reexamined and covalent/ionic characters of the intra- and inter-reactant communications in donor-acceptor systems are explored. The complementary A–B coordination is compared with its regional HSAB analog, and polarizational/relaxational flows in such reactive systems are explored.https://www.mdpi.com/2076-3417/9/6/1262chemical reactivity theoryHSAB principleinformation theoryquantum mechanicsregional complementarity rulevirial theorem
collection DOAJ
language English
format Article
sources DOAJ
author Roman F. Nalewajski
spellingShingle Roman F. Nalewajski
Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
Applied Sciences
chemical reactivity theory
HSAB principle
information theory
quantum mechanics
regional complementarity rule
virial theorem
author_facet Roman F. Nalewajski
author_sort Roman F. Nalewajski
title Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
title_short Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
title_full Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
title_fullStr Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
title_full_unstemmed Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
title_sort understanding electronic structure and chemical reactivity: quantum-information perspective
publisher MDPI AG
series Applied Sciences
issn 2076-3417
publishDate 2019-03-01
description Several applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradient information. Continuities of molecular probability and current distributions, reflecting the modulus and phase components of molecular wavefunctions, respectively, are summarized. Resultant measures of the entropy/information descriptors of electronic states, combining the classical (probability) and nonclassical (phase/current) contributions, are introduced, and information production in quantum states is shown to be of a nonclassical origin. Importance of resultant information descriptors for distinguishing the bonded (entangled) and nonbonded (disentangled) states of reactants in acid(A)–base(B) systems is stressed and generalized entropy concepts are used to determine the phase equilibria in molecular systems. The grand-canonical principles for the minima of electronic energy and overall gradient information allow one to explore relations between energetic and information criteria of chemical reactivity in open molecules. The populational derivatives of electronic energy and resultant gradient information give identical predictions of electronic flows between reactants. The role of electronic kinetic energy (resultant gradient information) in chemical-bond formation is examined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and changes of the overall structure information in chemical processes are addressed. The frontier-electron basis of the hard (soft) acids and bases (HSAB) principle is reexamined and covalent/ionic characters of the intra- and inter-reactant communications in donor-acceptor systems are explored. The complementary A–B coordination is compared with its regional HSAB analog, and polarizational/relaxational flows in such reactive systems are explored.
topic chemical reactivity theory
HSAB principle
information theory
quantum mechanics
regional complementarity rule
virial theorem
url https://www.mdpi.com/2076-3417/9/6/1262
work_keys_str_mv AT romanfnalewajski understandingelectronicstructureandchemicalreactivityquantuminformationperspective
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