Multiple Auger cycle photoionisation of manganese atoms by short soft x-ray pulses

Abstract

The multiple ionisation of atomic Mn, excited at (photon energy: 52.1 eV) and above (photon energy: 61.1 eV) the discrete giant $3p\mbox{--}3d$ resonance, was studied using high irradiation free-electron-laser soft x-ray pulses from the BL2 beamline of FLASH, DESY, Hamburg. In particular, the impact of the giant resonance on the ionisation mechanism was investigated. Ion mass-over-charge spectra were obtained by means of ion time-of-flight spectrometry. For the two photon energies, the yield of the different ionic charge states Mn ${}^{q+}$ ( q = 0–7) was determined as a function of the irradiance of the soft x-ray pulses. The maximum charge state observed was Mn ^6+ for resonant excitation at 52.1 eV and Mn ^7+ for non-resonant excitation at 61.1 eV at a maximum irradiation of $3\times {10}^{13}\ {\bf{W}}{\mathrm{cm}}^{-2}$ .

Keywords

• nonlinear photoionisation
• short x-ray pulses
• atomic open shell system