Photoionization of Cl⁺from the 3s²3p^4 3P_2,1,0and the 3s²3p^4 1D₂,¹S₀states in the energy range 19–28 eV

Abstract

Absolute photoionisation cross sections for the Cl + ion in its ground and the metastable states; 3s 2 3p 4 3 P 2,1,0 , and 3s 2 3p 4 1 D 2 , 1 S 0 , were measured recently at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory using the merged beams photon-ion technique at an photon energy resolution of 15 meV in the energy range 19 -28 eV. These measurements are compared with large-scale Dirac Coulomb R-matrix calculations in the same energy range. Photoionisation of this sulphur-like chlorine ion is characterized by multiple Rydberg series of autoionizing resonances superimposed on a direct photoionisation continuum. A wealth of resonance features observed in the experimental spectra are spectroscopically assigned and their resonance parameters tabulated and compared with the recent measurements. Metastable fractions in the parent ion beam are determined from the present study. Theoretical resonance energies and quantum defects of the prominent Rydberg series 3s 2 3p 3 nd, identified in the spectra as 3p → nd transitions are compared with the available measurements made on this element. Weaker Rydberg series 3s 2 3p 3 ns, identified as 3p → ns transitions and window resonances 3s3p 4 ( 4 P )np features, due to 3s → np transitions are also found in the spectra.

Photoionization Study of Cl II, Ar II and Kr II Ions Using the Modified Atomic Orbital Theory

“…Table 5 is seen to agree very well with the uncertain ALS measurement [4] at (25.660 eV). A slight discrepancy is observed when comparing with the corresponding DCR calculation [5] equal to 25.668 eV. Comparison indicates clearly that the ALS value [4] is correct at 25.660 eV.…”

“…The electric charge of the core ion is deduced directly from the single Photoionization process for a given X p+ -plasma ion Cl II ions are listed in Tables 1-8. Comparisons of the present MAOT calculations are done with the available Dirac-Coulomb R-matrix (DCR) calculations [5] and with the ALS experimental data [4]. For both the DCR [5] and ALS [4] studies, the determination of the resonances energies have been limited to n = 13 (see Table 4).…”

“…Comparisons of the present MAOT calculations are done with the available Dirac-Coulomb R-matrix (DCR) calculations [5] and with the ALS experimental data [4]. For both the DCR [5] and ALS [4] studies, the determination of the resonances energies have been limited to n = 13 (see Table 4). In general due to interaction configuration and other electron-electron effects, the peaks of the cross section overlap involving difficulty for the identification of lines in the atomic spectra with increasing n. But Table 3 where the MAOT prediction at 25.001 eV agree very well with both the DCR value at 24.999 eV [5] and the uncertain ALS measurement [4] equal to (25.000 eV).…”

“…Resonance energies (E) and quantum defect (δ) of the [ metastable state of the Cl + ions converging to the Cl 2+ . The present results from the Modified atomic orbital theory (MAOT) are compared with the Dirac-Coulomb R-matrix (DCR) calculations of McLaughlin[5] and with the ALS experimental data of Hernández et al,[4]. The ALS experimental resonance energies are calibrated to ±0.013 eV.…”

Photoionisation of Ca+ions in the valence-energy region 20–56 eV: experiment and theory

“…Ar + [71], and Co + [72], valence-shell studies on neutral sulfur [73], sulfur-like chlorine, Cl + [74], copper-like zinc, Zn + [75], tungsten and its ions, W [76] [48] and W 63+ [78] have been made using these DARC codes. Suitable agreement of the DARC photoionisation cross-sections with high resolution measurements performed at leading synchrotron light sources was obtained.…”