Photoelectron-photofragment coincidence spectroscopy of NO_2~-(NO)_(1,2): solvation effects of NO on NO_2~-

摘要

A study of the dissociative photodetachment dynamics of N_2O_3 - and N_3O_4~- at 258 nm is reported. Using photoelectron-photofragment coincidence (PPC) spectroscopy, information on the energetics and dissociation dynamics is recorded for both N_xO_y~- species. The results indicate that these anions exist as NO_2 - (NO)_(1,2) clusters, and dissociation occurs to form NO and NO_2 products upon photodetachment of the extra electron. It is shown that the energy released in the solvation of NO_2~- with one and two NO molecules is 0.23 ± 0.05 and 0.38 ± 0.05 eV, respectively. The photoelectron spectra show that solvation of NO_2~- by one NO does not significantly affect the electronic structure of the anion. The addition of a second NO to NO_2~-(NO), however, leads to a suppression of photodetachment to the A~2B_2 excited state of NO_2 in the NO_2(NO)_2 cluster. The data also suggests that the three-body dissociation process of the larger cluster may occur via a sequential decay mechanism.