What do kinetic‐energy anisotropies tell us about chemical bonding? I. Diatomic hydrides

Abstract

The kinetic-energy anisotropies of fifteen diatomic hydrides AH with A = H, Li, Be, B, C, N, 0, F, Na, Mg, Al, Si, P, S , CI are calculated from self-consistent-field wave functions constructed from extended basis sets of Slater-type orbitals. It is found that there. is no consistent ordering of the bond-parallel and bond-perpendicular components of the kinetic energy with respect to separated atom values. An analysis of the orbital contributions reveals that nonbonding ?r orbitals make large contributions to the total kinetic-energy anisotropy. This makes it difficult, if not impossible, to deduce anything about the nature of the chemical bond fmm the total anisotropy. However, certain dimensionless orbital kinetic-energy anisotropies are useful for interpretative studies because, in free atoms, these quantities have fixed values that depend only on the symmetry of the orbital.

Chemical Notions from the Electron Density

“…Berlin's partition of eq 12 is not the only way to look at chemical bonding. Since energy and its components are scalars, instead of dividing the nuclear attraction term into two parts, one could divide the kinetic energy, or the electron repulsion, or some combination of both, and define constants involving parts of these quantities, as it has been implicitly done in studies of the chemical bond based on the kinetic energy density [39][40][41][42][43][44][45][46] or in conventional explanations based on the electron pair density.…”

Spatial partitioning of the molecular wave function: Reexamination of the bond‐charge model of covalent binding

“…18.) The result is: Here, we have taken account of the two components of momentum transverse to the bond axis and the one parallel, thus accounting for the kinetic energy anisotropy in the overlap region 19. (2κ n multiplies the two terms on the right‐hand side of Eq.…”