Covalent Bonding: The Fundamental Role of the Kinetic Energy
- 2 August 2013
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry A
- Vol. 117 (33), 7946-7958
- https://doi.org/10.1021/jp403284g
Abstract
This work addresses the continuing disagreement between two prevalent schools of thought concerning the mechanism of covalent bonding. According to Hellmann, Ruedenberg, and Kutzelnigg, a lowering of the kinetic energy associated with electron delocalization is the key stabilization mechanism. The opposing view of Slater, Feynman, and Bader has maintained that the source of stabilization is electrostatic potential energy lowering due to electron density redistribution to binding regions between nuclei. Despite the large body of accurate quantum chemical work on a range of molecules, the debate concerning the origin of bonding continues unabated, even for H2+, the simplest of covalently bound molecules. We therefore present here a detailed study of H2+, including its formation, that uses a sequence of computational methods designed to reveal the relevant contributing mechanisms as well as the spatial density distributions of the kinetic and potential energy contributions. We find that the electrostatic mechanism fails to provide real insight or explanation of bonding, while the kinetic energy mechanism is sound and accurate but complex or even paradoxical to those preferring the apparent simplicity of the electrostatic model. We further argue that the underlying mechanism of bonding is in fact of dynamical character, and analyses that focus on energy do not reveal the origin of covalent bonding in full clarity.Keywords
This publication has 47 references indexed in Scilit:
- Why do molecules interact? The origin of electron donor-acceptor complexes, hydrogen bonding and proton affinityAccounts of Chemical Research, 1977
- The Physical Mechanism of the Chemical BondAngewandte Chemie-International Edition, 1973
- The Physical Nature of the Chemical BondReviews of Modern Physics, 1962
- Forces in MoleculesPhysical Review B, 1939
- Zur Rolle der kinetischen Elektronenenergie für die zwischenatomaren KräfteThe European Physical Journal A, 1933
- Quantentheoretische Beitr ge zum Problem der aromatischen und unges ttigten Verbindungen. IIIThe European Physical Journal A, 1932
- Quanstentheoretische Beiträge zum BenzolproblemThe European Physical Journal A, 1931
- Quantentheoretische Beiträge zum BenzolproblemThe European Physical Journal A, 1931
- Zur Quantentheorie der DoppelbindungThe European Physical Journal A, 1930
- Wechselwirkung neutraler Atome und homöopolare Bindung nach der QuantenmechanikThe European Physical Journal A, 1927