K-shell photoionization of Be-like boron (B⁺) ions: experiment and theory

Abstract

View the article online for updates and enhancements. AbstractAbsolute cross sections for the K-shell photoionization of Be-like boron ions were measured with the ion-photon merged-beams technique at the Advanced Light Source synchrotron radiation facility. High-resolution spectroscopy with E/ E up to 8800 ( E ∼ 22 meV) covered the energy ranges 193.7-194.7 eV and 209-215 eV. Lifetimes of the strongest resonances are determined with relative uncertainties down to approximately 4% for the broadest resonance. The measured resonance strengths are consistent with 60% 1s 2 2s 2 1 S ground-state and 40% 1s 2 2s2p 3 P o metastable-state ions in the primary ion beam and confirmed by comparison with independent absolute photo-recombination heavy-ion storage-ring measurements with B 2+ ions using the principle of detailed balance. Experimental determination of the line width for the 1s2s 2 2p 1 P o resonance gives a value of 47 ± 2 meV and compares favourably to a theoretical estimate of 47 meV from the R-matrix with pseudo-states (RMPS) method. The measured line widths of the 1s2s2p 2 3 P, 3 D resonances are 10.0 ± 2 meV and 32 ± 3 meV, respectively, compared to RMPS theoretical estimates of 9 meV and 34 meV.

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

“…Those lifetimes were found to be 6.3±0.9fs for the 2 D term, 11.2±1.1fs for the 2 P term, and 5.9±1.3fs for the 2 S term in an attempt similar to the present study where the natural widths of levels are determined by exciting the K shell of a singly ionized ion, i.e., of levels that are usually prepared by removing an electron from a neutral atom  (Schlachter et al 2004). The lifetime of a similarly produced K-vacancy level, ( ) + s s p B 1 2 2 P 2 1 1 , was found to be 14.0±0.6fs (Müller et al 2014). Comparison of these results indicates a strong reduction of the lifetime of such levels as a function of the atomic number Z.…”

“…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.…”

Fusion-Related Ionization and Recombination Data for Tungsten Ions in Low to Moderately High Charge States

“…Absolute cross sections with high energy resolution were determined over wide energy ranges. The idea for the measurements with tungsten ions was to exploit, firstly, the time-reversal relation between recombination and photoionization [109][110][111][112][113][114][115][116][117][118][119][120], and secondly, to contribute to the exploration of the electronic structure of tungsten ions. It is known that the plasma density in a fusion device is low so that absorption of high-energy photons is unlikely.…”

Near L-edge Single and Multiple Photoionization of Singly Charged Iron Ions

“…More distantly related experimental work comprises the spectroscopy of the L-shell emission -as is observed, e.g., in X-ray spectra of active galactic nuclei (Fabian et al 2009) -from electron-impact excitation of highly ionized iron ions at an EBIT (Gu et al 2001;Chen et al 2006;Beiersdorfer et al 2013), photoexcitation of highly charged iron ions in an EBIT (Epp et al 2007;Bernitt et al 2012;Rudolph et al 2013;Steinbrügge et al 2015), 3p detachment from Fe − (Dumitriu et al 2010), and electron-impact ionization and electron-ion recombination of multiply-charged iron ions in a heavy-ion storage ring (e.g., Savin et al 2002;Schippers et al 2010;Bernhardt et al 2014;Hahn et al 2015). The latter process can be viewed as the timeinverse of photoionization and is therefore very suitable to test corresponding theories (Schippers et al 2002;Müller et al 2009;Müller et al 2014).…”