Scientists capture first real-time images of electrons breaking bonds

Scientists from Shanghai Jiao Tong University have achieved a breakthrough by capturing the first real-time images of electrons and atomic nuclei moving simultaneously as a molecule breaks bonds. Using an advanced ultrafast electron diffraction (UED) technique combined with a novel charge pair distribution function (CPDF) analysis, the team was able to visualize electronic and atomic motion in ammonia (NH₃) molecules during photodissociation. This process involved exciting an electron from a nitrogen lone pair orbital to an anti-bonding orbital, triggering structural changes including an umbrella-like bending motion and the breaking of an N–H bond. Traditional diffraction methods could track atomic nuclei but lacked the sensitivity to detect electron density changes. By pushing UED to unprecedented spatial and temporal precision and employing CPDF analysis, the researchers successfully separated and mapped nucleus–nucleus, electron–nucleus, and electron–electron interactions in real time. This allowed them to observe how valence electrons shifted and how hydrogen atoms—typically difficult to track due to