Dissociation of High-Lying Electronic States of NO2+ in the 15.5-20 eV Region

We present a dissociative photoionization study of NO2 in the 15.5-20 eV energy range using synchrotron radiation-based double imaging photoelectron photoion coincidence (i 2 PEPICO) spectroscopy. The high-lying electronic states of the NO2+ cation, c B-3(1), C B-1(1), d (3)A(1), e B-3(2), and D B-1(2), are prepared in well-resolved vibronic states in order to study their individual dissociation mechanisms. Up to eight dissociation limits of NO2+ are reached, and mass-selected threshold photoelectron spectra (TPES) show that the c B-3(1), C B-1(1), and d (3)A(1) states predominantly dissociate into the NO+ + O products, while the e B-3(2) and D B-1(2) states can undergo fragmentation into both the NO+ + O and the O+ + NO channels, as well as the O-2(+) + N channel with a small yield. Overall, these product yields are found to be quite sensitive to autoionization processes. Mass-selected high-resolution electron and ion kinetic energy correlation diagrams reveal dissociative mechanisms that possess strong state-specific character.

Automated summary

A study of dissociative photoionization of high-lying electronic states of NO2 showed that the product yields are sensitive to autoionization processes, with different states dissociating into different products. The dissociative mechanisms have strong state-specific character, as observed in high-resolution electron and ion kinetic energy correlation diagrams.