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

We have obtained rotationally resolved pulsed field ionization photoelectro n (PFI-PE) spectra of NO in the energy range of 15.6-18.2 eV, covering ioni zation transitions of NO+(a (3)Sigma(+),v(+)=0-16,J(+))<-- NO(X (2)Pi(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 spe ctroscopic data for these states. The simulation of these PFI-PE bands prov ides accurate molecular constants for NO+(a (3)Sigma(+),v(+)=0-5,7-10,12-14 ,16), including ionization energies, vibrational constants (omega(e)(+)=129 5.2 +/- 0.1 cm(-1), omega(e)(+)chi(e)(+)=15.198 +/- 0.002 cm(-1)), and rota tional 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 val ue and intensities of higher Delta J branches as v(+) (or bond distance) fo r NO+(a (3)Sigma(+)) is increased. This observation can be taken as strong support of the electron-molecular-ion-core scattering model for angular mom entum and energy exchanges in the threshold photoionization of NO. (C) 1999 American Institute of Physics. [S0021-9606(99)01027-2].