Relationship between interference pattern and molecular orbital shape in (e, 2e) electron momentum profiles of SF6

We report an (e, 2e) study on interference effects in the spherically-averaged electron momentum density distributions of the five outermost molecular orbitals (MOs) of SF6, which are each constructed from the 2p atomic orbitals (AOs) on the F atoms. The (e, 2e) experiment was performed in the symmetric noncoplanar geometry and at an incident electron energy of 1.2 keV. Interference patterns for each MO have then been obtained by dividing the experimental data by distorted-wave-Born-approximation cross section for an isolated F2p AO. A detailed analysis of the results shows that the interference patterns afford a rare opportunity to experimentally clarify symmetries of the MOs. Furthermore, it is demonstrated that they provide information about not only the molecular geometry but also the spatial orientation of the constituent AOs even for this relatively complicated molecule. (C) 2016 Elsevier B.V. All rights reserved.