Capturing attosecond delays in electronic and vibrational dependent photoemission of NO molecules

Timing the photoionization process reveals electron motion through the molecular potential and the interplay between electronic and nuclear dynamics. Here we show, using attosecond interferometry with high energy resolution, that photoionization delays in nitric oxide depend on the electronic state and vibrational level of the molecular ion. We observe significant delays among channels leading to different electronic states, in agreement with scattering calculations. In contrast, delays among vibrational levels of the ground electronic state are negligible in an energy range without significant resonances. These results attribute this difference to the influence of resonant electronic structures on electron propagation, which establish photoionization delays as a sensitive probe of the molecular potential. Despite averaging over molecular orientations, the agreement between experiment and theory provides a valuable test of the theoretical description and supports the interpretation of electron dynamics in heteronuclear molecules.