Publication Date
8-30-2018
Department
Ames Laboratory; Chemistry
Campus Units
Chemistry, Ames Laboratory
OSTI ID+
1472189
Report Number
IS-J 9749
DOI
10.1021/acs.jpca.8b08234
Journal Title
Journal of Physical Chemistry A
Volume Number
122
Issue Number
39
First Page
7880
Last Page
7893
Abstract
A long-held view of the origin of covalent binding is based on the notion that electrostatic forces determine the stability of a system of charged particles and that, therefore, potential energy changes drive the stabilization of molecules. A key argument advanced for this conjecture is the rigorous validity of the virial theorem. Rigorous in-depth analyses have however shown that the energy lowering of covalent bonding is due to the wave mechanical drive of electrons to lower their kinetic energy through expansion. Since the virial theorem applies only to systems with Coulombic interaction potentials, its relevance as a foundation of the electrostatic view is tested here by calculations on analogues of the molecules H2+ and H2, where all 1/r interaction potentials are replaced by Gaussian-type potentials that yield one-electron “atoms” with realistic stability ranges. The virial theorem does not hold in these systems, but covalent bonds are found to form nonetheless, and the wave mechanical bonding analysis yields analogous results as in the case of the Coulombic potentials. Notably, the key driving feature is again the electron delocalization that lowers the interatomic kinetic energy component. A detailed discussion of the role of the virial theorem in the context of covalent binding is given.
DOE Contract Number(s)
AC02-07CH11358
Language
en
Department of Energy Subject Categories
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Publisher
Iowa State University Digital Repository, Ames IA (United States)
