Visualizing Covalency and Multiple Bonds in Terms of the Electronic Single-Particle Density Matrix

Abstract

Two-dimensional cuts through spin-integrated single-particle density matrices (SPDMs) have proven to be a valuable tool to discuss the nature of chemical bonding independent of the degree of rotation of the underlying orbitals in Hilbert space. Starting from a straightforward concept for the interpretation of σ bonds, we briefly present how the transition from purely ionic to mainly covalent bonding is mirrored in the off-diagonal features of the SPDM in the isoelectronic series LiF, BeO and BN. Furthermore, we outline one of several possible ways to extend the graphical representation and interpretation of SPDMs to the case of π bonds in organic molecules and apply it to the conjugated π-electron system 1,6-hexadiynediol.

Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps

“…Using machine-learning techniques, these data sets will be crosscorrelated with information from property databases. An intriguing possibility would be to study regression maps between the bond measures [398,399] and low-dimensional charge density descriptors [400][401][402] and final macroscopic observables.…”