Absolute, State‐selective Measurements of the Photoionization Cross Sections of N ⁺ and O ⁺ Ions

Low-energy fine-structure resonances in photoionization of O ii

“…They are expected to significantly enhance the very-low-temperature dielectronic recombination rates, potentially leading to the resolution of an outstanding nebular abundances anomaly. Higher energy partial and total photoionization cross sections of the ground configuration levels 2p 3 ( 4 S o 3/2 , 2 D o 3/2,5/2 , 2 P o 1/2,3/2 ) are found to be in agreement with experimental measurements on synchrotron-based photon sources [1][2][3], thereby identifying the excited O III levels present in the ion beams. These are also the first results from a recently developed version of Breit-Pauli R-matrix (BPRM) codes, with inclusion of two-body magnetic interaction terms.…”

“…Singly ionized O II has been extensively studied experimentally [1][2][3] as well as theoretically [4,5]. Using synchrotron-based photon sources such as the Advanced Light Source (ALS) [1,3], high-resolution experimental measurements of photoionization cross sections of O II reveal a number of Rydberg series of resonances converging on various excited states of the residual ion O III.…”

Photoionization cross sections of O II, O III, O IV, and O V: BenchmarkingR-matrix theory and experiments

“…The figure has seven panels: the lowest three panels, Figs. 1(a)-1(c [5] and by Kjeldsen et al [7], respectively. tinct resonance series seen in the low-energy region of Fig.…”

“…Each of these three sophisticated experimental setups has different advantages in measurements, and the results often complement each other. Cross sections for O II have been measured at ALS for nearthreshold features in PI of metastable states [5], and later extended to a wider photon energy range [6], and at the University of Aarhüs [7]. Detailed photoionization cross sections have recently been measured for the ground and low excited states of multiply charged oxygen ions for the first time for O III, O IV, and O V, at the synchrotron radiation source at University of Paris-Sud [8].…”

Absolute cross sections for L-shell photoionization of the ions N$\mathsf{^{2+}}$, N$\mathsf{^{3+}}$, O$\mathsf{^{3+}}$, O$\mathsf{^{4+}}$, F$\mathsf{^{3+}}$, F$\mathsf{^{4+}}$ and Ne$\mathsf{^{4+}}$

“…For a review of the previous works, see West (2001). In particular, the experiments performed on L-shell photoionization include the ions B + (Schippers et al 2003), C + (Kjeldsen et al 1999a(Kjeldsen et al , 2001), C 2+ (Müller et al 2002), N + (Kjeldsen et al 2002a), O + (Kjeldsen et al 2002a;Covington et al 2001;Aguilar et al 2003), O 2+ -O 4+ (Champeaux et al 2003), and Ne + (Covington et al 2002). In most of these studies absolute cross sections have been measured and often good agreement was found with the results of R-matrix calculations.…”