Rotational-resolved pulsed field ionization photoelectron study of NO~+ (a ~3#SIGMA#~+, v~+ = 0 - 16) in the energy range of 15.6-18.2 eV

摘要

We have obtained rotationally resolved pulsed field ionization photoelectron (PFI-PE) spectra of NO in the energy range of 15.6 - 18.2 eV, covering ionization transitions of NO~+ (a ~3#SIGMA#~+, v~+ = 0 - 16,J~+) <- NO(X ~2II_(3/2,1/2),v" = 0,J"). The PFI-PE bands for NO~+(a ~3#SIGMA#~+, v~+ = 1 - 5,7 - 10,12 - 14,16) obtained in this experiment represent the first rotationally resolved spectroscopic data for these states. The simulation of these PFI-PE bands provides accurate molecular constants for NO~+(a ~3#SIGMA#~+, v~+ = 0 - 5,7 - 10,12 - 14,16), including ionization energies, vibrational constants (#omega#_e~+ = 1295.2 +- 0.1 cm~(-1), #omega#_e~+X_e~+ = 15.198 +- 0.002 cm~(-1), and rotational constants (B_e~+ = 1.3501 +- 0.0070 cm~(-1), #alpha#_e ~+ = 0.0206 +- 0.0001 cm~(-1)). As observed in the PFI-PE study of NO~+ (X ~1#SIGMA#~+), this experiment reveals a generally increasing trend for the maximum #DELTA#J value and intensities of higher #DELTA#J branches as v~+ (or bond distance) for NO~+(a ~3#SIGMA#~+) is increased. This observation can be taken as strong support of the electron-molecular-ion-core scattering model for angular momentum and energy exchanges in the threshold photoionization of NO.