Bond Order Densities in Real Space

Abstract

In this contribution we introduce the concept of bond order density (BOD) based on previous work on natural adaptive orbitals. We show that BODs may be used to visualize both the global spatial distribution of the covalent bond order as well as its eigen-components, which we call bond(ing) channels. BODs can be equally computed at correlated and non-correlated levels of theory, and in ground or excited states, thus offering an appealing description of bondforming, bond-breaking, and bond-evolution processes. We show the power of the approach by examining a number of homo-and hetero-diatomics, including the controversial existence of a fourth bonding component in dicarbon, by analyzing a few interesting bonding situations in polyatomics and chemical transformations, and by exemplifying exotic bonding behaviors in simple excited electronic states.

A Genuine Stannylone with a Monoatomic Two‐Coordinate Tin(0) Atom Supported by a Bis(silylene) Ligand

“…In other words, the Sn atom in 4 accepts electrons from the two adjacent donor Si II atoms and donates electrons to Fe, forming four dative bonds with the Si and Fe atoms. Furthermore, these four donating interactions between Sn and four adjacent atoms (two Si and two Fe) are consistent with the results of the natural adaptive orbital (NAdO) analysis [20] (Figure S28). Specifically, four σ‐type NAdOs are determined with close‐to‐one eigenvalues, 0.826, 0.806, 0.703 and 0.660, respectively.…”

On the Nature of Bonding in the Photochemical Addition of Two Ethylenes: C-C Bond Formation in the Excited State?

“…We propose this prediction a challenge to be further tested from other theoretical methodologies. 20,22,23,25,26,30,34 Certainly, a defying quest from the experimental point of view. 18,19,60 Regarding a more subtle formal detail, our findings also confirm recent conclusions that bonding events in asymmetric electronic interactions as the thermal 4s+2s Diels-Alder reaction 44 and the photochemically induced 2s+2s cycloaddition of two ethylenes via MECI can be rationalized in terms of the simplest Thom's universal unfolding.…”

“…In the absence of detailed studies concerning the bonding situation of such a prototypical reaction mechanism, in this work, we aimed to get a complete characterization of the bonding phenomena of the process in the real space. 23,30 Within such a goal, we resort to the topological analysis of the electron localization function (ELF). 31 In complement to the analysis of other functions as electron density (i.e., QTAIM 32 ), within the so-called quantum topological framework of approaches, 20,22,23,26,33,34 ELF provides a simple, straightforward connection to the chemical bonding concept, 35,36 as it can be understood as a local measure of the Pauli repulsion.…”

mwfn: A Strict, Concise and Extensible Format for Electronic Wavefunction Storage and Exchange

“…Definitions of all subfields for each orbital are shown below, the order of appearance should not be altered. This field can also be used to record eigenvalues of natural transition orbitals (NTO), [10] natural adaptive orbitals [11] and so on.…”