Rotationally resolved pulsed-field ionization photoelectron bands for O_2~+(A ~2II_#mu#, V~+=0-12) in the energy range of 17.0-18.2 eV

摘要

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFE-PE) spectra for O_2 in the energy range of 17.05-18.13 eV, covering the ionization transitions O_2~+(A ~2II_#mu#, #upsilon#~+ =0-12,N~+)<-O_2(X~3#SIGMA#_g~-,#upsilon#"=0,N"). Although these O_2~+(A ~2II_#mu#, #upsilon#~+) PFI-PE bands have significant overlaps with vibrational bands for O_2~+(a ~4II_#mu#) and O_2~+(X~2II_g), we have identified all the O_2~+(A ~2II_#mu#, #upsilon#~+ =0-12) bands by simulation of spectra obtained using supersonically cooled O_2 samples with rotational temperatures ≈20 and 220 K. While these #upsilon#~+ =0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O_2~+(A ~2II_#mu#), the PFI-PE bands for O_2~+(A ~2II_#mu#, #upsilon#~+ =9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O_2~+(A ~2II_#mu#, #upsilon#~+ =0.12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O_2~+(A ~2II#mu#, #upsilon#~+ =9 and 10) states are strongly perturbed by a nearby electronic state.