Göttingen physicists reconstruct 3D molecular orbital with tabletop soft X-ray laser

An interdisciplinary group at the University of Göttingen imaged the three-dimensional wavefunction of a nanometer-sized organic molecule by combining photoelectron spectroscopy with mathematical reconstruction, SciTechDaily reported of results in Nature Communications. Quantum mechanics describes an electron through a wavefunction that gives probabilities for properties such as position and momentum. In molecules those wavefunctions are molecular orbitals whose shapes encode how a molecule may absorb light, interact with surroundings, or react. Professor Stefan Mathias said the wavefunction is fundamental yet cannot be directly observed or measured. The team used photoelectron spectroscopy to measure momenta of electrons emitted from the molecule, revealing one half of the wavefunction without changing its state. Algorithms calculated the missing half, reconstructing the complete molecular orbital with features smaller than the spacing between neighboring carbon atoms. Previously, extending the technique into three dimensions required lengthy measurements at large-scale synchrotron facilities, limiting wider use, the writeup said.