Effects of initial-state laser excitation on inner-shell photoionization and Auger decay of Rb

The $3d^{-1}$ photoionization and subsequent $M_{4,5}{N}_{2,3}{N}_{2,3}$ Auger electron spectra of free initially laser-excited rubidium atoms have been investigated. The rubidium atoms were excited from the ground state $\left[\mathrm{Kr}\right]5s_{1∕2}$ to the $\left[\mathrm{Kr}\right]5p_{1∕2}$ and $\left[\mathrm{Kr}\right]5p_{3∕2}$ states. Emphasis was put on the changes in coupling and electron correlation between the three different initial states. The ground state $3d$ photoelecton spectrum of free Rb atoms was interpreted in detail. The binding energies for $3d_{3∕2,5∕2}$ orbitals of initially ground-state and laser-excited Rb atoms were obtained. Extensive multiconfiguration Dirac-Fock calculations performed in the relativistic $jj$ coupled basis were compared to the experimental photoelectron and Auger electron spectra.

Figure 1

Experimental $3d$ photoelectron spectrum of Rb measured at the photon energy of $200\mathrm{eV}$. For better visualization the binding energy region of $122–127\mathrm{eV}$ is magnified.

Figure 2

(Color online) Experimental $3d$ PES of Rb measured with laser on and off. The solid line is the ground-state spectrum, the dotted red line is the spectrum measured with laser in $5s_{1∕2}\to 5p_{1∕2}$ resonance, and the dashed blue line is the spectrum measured with laser in $5s_{1∕2}\to 5p_{3∕2}$ resonance at laser polarization angle of 45° with respect to the synchrotron polarization.

Figure 3

(Color online) Subtracted spectra between (a) laser in $5s_{1∕2}\to 5p_{1∕2}$ resonance and laser off spectrum, (b) laser in $5s_{1∕2}\to 5p_{3∕2}$ resonance and laser off spectrum. Dots are the original data points, solid lines are the fits, and the dashed lines denote the zero level.

Figure 4

Fit to the experimental spectra (a) and (b) calculated $3d^{-1}$ PES from initially $5p_{1∕2}$ excited (dashed lines) and $5p_{3∕2}$ excited (solid lines) Rb. The labels refer to the peaks at the same energy range in the two spectra from $5p_{1∕2}$ and $5p_{3∕2}$ initial states in (a) and (b).

Figure 5

Calculated $3d_{3∕2,5∕2}^{-1}$ photoemission main lines from the (a) $K\left(5s_{1∕2}\right)$ initial state, (b) $K^{*}\left(5p_{1∕2}\right)$ excited initial state, and (c) $K^{*}\left(5p_{3∕2}\right)$ excited initial state of Rb.

Figure 6

(Color online) Experimental $M_{4,5}{N}_{2,3}{N}_{2,3}$ Auger spectra of Rb measured with laser on and off. The solid black line is the ground-state spectrum, the dotted red line is the spectrum measured with laser in $5s_{1∕2}\to 5p_{1∕2}$ resonance, and the dashed blue line is the spectrum measured with laser in $5s_{1∕2}\to 5p_{3∕2}$ resonance. The sticks denote the lines obtained from the fit done to the ground-state spectrum.

Figure 7

(Color online) Experimental (a) and (b) calculated $M_{4,5}{N}_{2,3}{N}_{2,3}$ AES from initially $5p_{1∕2}$ excited (dotted red lines) and $5p_{3∕2}$ excited (solid black lines) Rb. The dashed line in (a) denotes the zero level.

Figure 8

Calculated $M_{4,5}{N}_{2,3}{N}_{2,3}$ AES from (a) nonexcited states, (b) initially $5p_{1∕2}$ excited states, and (c) $5p_{3∕2}$ excited states of Rb. The spectra in panels (b) and (c) are shifted $1.2\mathrm{eV}$.