Revised interpretation of the photoionization of Cr⁺in the 3p excitation region

Abstract

The absolute cross section for photoionization of Cr+ has been measured using the merged-beam technique, focusing on the region of the ‘giant’ resonance. These new absolute data differ considerably from previous experimental data, with the result that the agreement between experiment and existing calculations has improved substantially. The neutral and ionized Cr spectra, previously believed to be completely different, are shown here to be rather similar. The role of the 3d5(6S) state in determining the special position of Cr among the 3d elements is emphasized. The experimental data are available at http://www.phys.au.dk/amo/atomphys/atomphys.htm.

Potential barrier effects in high-order harmonic generation by transition-metal ions

“…Thus, to obtain the photorecombination cross sectionσ (E) we need both the total photoionization cross section σ and the angular distribution asymmetry parameter β(E). The total photoionization cross section is available from both experimental measurements [21,[23][24][25] and theoretical calculations [22,[26][27][28], whereas the asymmetry parameters are mostly available from theoretical calculations [22,27,29]. However, our results for Cr + in Figs.…”

Harmonic generation in laser-produced plasmas containing atoms, ions and clusters: a review

“…Indeed, the reported transitions of Cr ions in the range above 40 eV showed high values of oscillator strengths. Previous studies of the photoabsorption and photoionisation spectra of Cr plasma at 41-42 eV have revealed the presence of strong transitions at this range [135][136][137]. In particular, the region of the 'giant' 3p-3d resonance of Cr(II) spectra was analysed in [137], and strong transitions, which could enhance the nonlinear optical response of the chromium plasma plume, were revealed.…”

New Approaches in Frequency Conversion of Laser Radiation in Plasma Plumes

“…The enhancement of a single harmonic can be attributed to the broadband resonances of the ions of few metals, such as V, In, Cd, Cr, Cd, and Mn. These "giant" resonances have been experimentally confirmed in the literature [26,28,29] and discussed recently in a few theoretical studies [7,[30][31][32]. However, in previous studies using multi-cycle pulses, the intensity of enhanced harmonics was only a few times higher compared with those neighboring harmonic orders.…”