Ion Energy-Loss Spectroscopy of Kr²⁺–He and –Ne Collisions. I. Transitions among ³P₂, ³P₁, ³P₀, ¹D₂ and ¹S₀ of Kr²⁺

Abstract

Excitation and de-excitation among low-lying states of Kr 2+ , 3 P 2 , 3 P 1 , 3 P 0 , 1 D 2 and 1 S 0 , in the collisions with He and Ne are studied in the energy range from 0.5 to 2.7 keV using a high resolution ion energy-loss spectrometer. The primary Kr 2+ beam is extracted from an electron-impact ton source and the fractional populations of these states are determined as a function of the impact energy for electrons from 80 to 400 eV. The measured fractions are different from those expected from the statistical model. The fractional populations of the metastable states, 1 D 2 and 1 S 0 , increase monotonously with the increase of the electron energy up to the highest energy studied. The cross sections for the 3 P 2 ↔ 3 P 1 , 3 P 2 ↔ 3 P 0 , 3 P 0,1 ↔ 1 D 2 and 1 D 2 ↔ 1 S 0 transitions are evaluated from the intensities of the inelastic and primary peaks observed at angle 0°.