K-shell photoionization of B-like atomic nitrogen ions: experiment and theory

Abstract

Measurements of absolute cross sections for the K-shell photoionization of B-like atomic nitrogen ions were carried out utilizing the ion-photon merged-beam technique at the SOLEIL synchrotron radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/ E ≈13,500 was the maximum resolution achieved. We have investigated two photon energy regions: 404-409 eV and 439-442 eV. Resonance peaks found in the experimental measured cross sections are compared with theoretical estimates from the multi-configuration Dirac-Fock, R-matrix and empirical methods, allowing identification of the strong 1s → 2p and the weaker 1s → 3p resonances in the observed K-shell spectra of this B-like nitrogen ion.

Complex multireference configuration interaction calculations for the K-vacancy Auger states of N q+ (q = 2-5) ions

“…4. As shown in the table, for states Q, T, U, and V, the present CMRD-CI calculations are in excellent agreement with the available SOLEIL measurements, 3 as well as other calculations. 3,[8][9][10] For the other eight states R, S, W, X, Y, Z, Z ′ , and Z ′′ , very good agreements are achieved for different calculations.…”

“…3,[8][9][10] For the other eight states R, S, W, X, Y, Z, Z ′ , and Z ′′ , very good agreements are achieved for different calculations. 3,[8][9][10] It is interesting to show the spin-alignment phenomenon 59,60 in the present calculations of K-vacancy Auger states, namely, the Auger decay rate or Auger width depends on the spin-alignment for the pair K L 1 L 2 states with different multiplicities (e.g., states 1s[2s2p 1 For states N 5+ (2s 2 ) and N 5+ (2s2p), it is obvious that the two 2s electrons overlap more than the 2s and 2p electrons and the interactions of the two 2s electrons are stronger than the 2s and 2p electrons, the decay width of the former state should be larger than the latter one, which is consistent with the results shown in Table III. For states B [N 5+ (2s2p 1 P)] and C [N 5+ (2s2p 3 P)], the calculations show that the former one decays faster.…”

“…CMRD-CI is employed to compute the resonance positions and widths for a series of K-vacancy Auger states of nitrogen ions, including the 2s 2 1 S and 2s2p 1,3 Table I. The third column shows the type of Gaussian functions employed in the calculations, while the fourth and fifth columns show the dominant configurations and the dominant decay channels for each Auger state, respectively.…”

“…Shorman et al and Gharaibeh et al 2,3 recently measured the absolute cross sections for the K-shell PI of Li-like, Be-like, and B-like atomic nitrogen by employing the ion-photon merged-beam technique at the SOLEIL synchrotron radiation facility in Saint-Aubin, France. The PI cross section spectra are fitted into Fano profiles to extract the corresponding resonance widths.…”

Photoionization of Ne Atoms and Ne+ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

“…An overview of deep-inner-shell photoabsorption by atomic cations and anions has been provided recently by Müller (Müller 2015). Experimental data on K-shell photoionization and photoexcitation of positive ions with atomic numbers  Z 3 have been published for Li +  (Carroll & Kennedy 1977;Kiernan et al 1994;Mosnier et al 2000;Scully et al 2006), Be +  (Mehlmann & Esteva 1974), B + (Müller et al 2014), B 2+ (Müller et al 2010a), C + (Schlachter et al 2004;Müller et al 2015), C 2+ (Scully et al 2005), C 3+ (Müller et al 2009), N + (Gharaibeh et al 2011), N 2+ (Gharaibeh et al 2014) (Rudolph et al 2013;Steinbrügge et al 2015), Fe 24+ (Rudolph et al 2013), and Kr 34+ . K-shell photoionization experiments with neutral neon atoms have employed static gas targets, and a large body of papers has addressed specific features in the excitation and decay of K-shell vacancies in neon atoms.…”