Figure 1

The $4p$ inner shell photoabsorption spectrum of $\mathrm{Sr}\mathrm{II}$ recorded $1\mathrm{mm}$ from the target surface and $500\mathrm{ns}$ after plasma generation.Reuse & Permissions

Figure 2

(Color online) Photoabsorption spectrum of $\mathrm{Sr}\mathrm{II}$ (black) with the separately calculated spectra to show the effect of the $5p^2$ and $4d^2$ configurations on the $p^{5}ds$ level. (a) Transitions to the $4p^{5}5s$ $nd$, $ms$ level without configuration interaction. The predicted energy for the main resonance is slightly higher than observed. (b) The same as (a) including the $4p^{5}5p^2$ configuration. The main resonance has shifted down to lower energy, matching the experimental value well. Notice a redistribution of oscillator strength also, a reduction can be seen around $30–32\mathrm{eV}$ and some new peaks are observed $\sim 29\mathrm{eV}$ which can be attributed to the $5p^2$ configuration. (c) The same as (a) including the $4p^{5}4d^2$ configuration, the appearance of peaks to the left and right of the main resonance confirm their identification as belonging to this configuration. (d) The full calculation performed which gives good overall agreement with the observed photoabsorption spectrum (metastable contribution is not included and but account for the other peaks). All lines in the theoretical plot have been fitted with a Lorentzian width of $0.02\mathrm{eV}$ to match experiment.Reuse & Permissions

Figure 3

(Color online) Photoabsorption spectrum of $\mathrm{Sr}\mathrm{II}$ (top) with the separately calculated ground state absorption (middle) and metastable spectrum from the $4p^{6}4d$ ${}^{2}D_{3∕2,5∕2}$ states (bottom). All lines in the theoretical plot have been fitted with a Lorentzian width of $0.02\mathrm{eV}$ to match the experimental spectrum.Reuse & Permissions

Figure 4

Photoabsorption spectrum of $\mathrm{Sr}\mathrm{II}$ from $30.35\text{to}36.30\mathrm{eV}$ with the $\left(4p^{5}5s{}^{1}P\right)nd,ms$ ${}^{2}P$ series converging on the $4p^{5}5s$ ${}^{1}P_1$ and $4p^{5}5s$ ${}^{3}P_1$ core at 36.24 and $35.13\mathrm{eV}$, respectively.Reuse & Permissions