Researchers have experimentally confirmed a model to detect electron delocalization in molecules and crystals. The chemists have also illustrated examples on how the same approach have been used to obtain precious insights into the chemical bonding of a wide variety of systems, from metallorganic compounds to systems of biological relevance.
As electrons are quantum objects, they cannot be clearly identified (or, to use the scientific term, localized) in a particular place. This means that the behaviour of electrons cannot be described using equations that work with regular, non-quantum objects: instead of an electron as a ball within a molecule, scientists have to examine a blurred cloud. Developing a mathematical model to determine the distribution of electrons relatively quickly and accurately is one of the most significant challenges of modern science.
“The main novelty introduced by our study is the possibility of detecting electron delocalization directly from experimental data. Electron delocalization, which is a cornerstone paradigm of chemistry, could so far be estimated only through approaches relying on quantities not obtainable from experimental measurements, e.g. the so-called ‘delocalization index’. Our results may therefore pave the way for looking at this important phenomenon in a new fashion” – writes Gabriele Saleh, one of the co-authors of the study.
The mathematical model proposed in 1998 by the Canadian expert in quantum chemistry Richard Bader and the Italian researcher Carlo Gatti sees electron distribution in a crystal as the sum of contributions of so-called Source Functions. From this point of view, a molecule (or crystal) is seen as a set of individual elements, each of which contributes to the final distribution. This approach, as shown by subsequent studies, provides an insightful view of hydrogen bonds, metal-ligand bonds, and other types of chemical interactions.