First visualization of valence electrons reveals fundamental nature of chemical bonding

Good news! Amazing stuff!

"The distribution of outermost shell electrons, known as valence electrons, of organic molecules was experimentally observed for the first time by a team led by Nagoya University in Japan. As the interactions between atoms are governed by the valence electrons, their findings shine light on the fundamental nature of chemical bonds, with implications for pharmacy and chemical engineering. ..."

"... By conducting world-class synchrotron X-ray diffraction experiments at SPring-8, the group discovered that it is possible to selectively extract only the valence electron density of atoms in a crystal.

“We named this method the CDFS method. Using this method, we observed the electron state of the glycine molecule, a type of amino acid,” corresponding author Hiroshi Sawa said. “Although the method was relatively simple to perform, the result was impressive. The observed electron cloud did not exhibit the smooth, enveloping shape that many predicted, but rather a fragmented, discrete state.” ..."

From the abstract:

"Recent advent of diverse chemical entities necessitates a re-evaluation of chemical bond concepts, underscoring the importance of experimental evidence. Our prior study introduced a general methodology, termed Core Differential Fourier Synthesis (CDFS), for mapping the distribution of valence electron density (VED) in crystalline substances within real space. In this study, we directly compare the VED distributions obtained through CDFS with those derived from high-accuracy theoretical calculation using long-range corrected density functional theory, which quantitatively reproduces accurate orbital energies. This comparison serves to demonstrate the precision of the CDFS in replicating complex details. The VED patterns observed experimentally exhibited detailed structures and phases of wave functions indicative of sp3 hybrid orbitals, closely aligning with theoretical predictions. This alignment underscores the utility of our approach in gathering quantum chemical data experimentally, a crucial step for discussing the chemical properties, such as reaction mechanisms."

First visualization of valence electrons reveals fundamental nature of chemical bonding

First visualization of valence electrons reveals fundamental nature of chemical bonding (original news release)

Unveiling the Nature of Chemical Bonds in Real Space (no public access)

Direct observation of valence electron density was done by synchrotron radiation X-ray diffraction at SPring-8. Theoretical results using a quantum mechanical modelling method called density functional theory (DFT) matched with the observation.