“…Over the past three decades EMS experimental techniques have steadily improved the precision, accuracy, and detection efficiency of EMS measurements [25,28]. As a result, EMS measurements have been employed as benchmarks for evaluating the accuracy of theoretical calculations of molecular momentum distributions [35,36]. Moreover, owing to the sensitivity of valence electrons to the structure of a molecule, EMS can detect and study modifications of electron momentum densities due to molecular conformation changes [37], molecular pseudorotations [38], multicenter effects [39,40], or vibrations [41,42].…”