Charge-State Distributions after Beta Decay of ⁶He to Form ⁶Li⁺

Abstract

The shake-off processes and charge-state fractions of 6Li+, 6Li++, and 6Li3+ were studied following the beta decay of 6He in the 1s21S0, 1s2s1S0, and 1s2s3S1 initial states. The sudden approximation was used, together with fully correlated Hylleraas wave functions and pseudostates. A projection operator method was introduced to separate the charge-state fractions in the positive energy region of overlapping continua. The results show that 6Li++ (single-ionisation) remains dominant, even in the energy range E>0, where the formation of 6Li3+ (double-ionisation) is energetically allowed. The results reduce disagreements with the experiment for the fraction of 6Li3+ by nearly an order of magnitude, but substantial disagreements remain that are inconsistent with the sudden approximation widely used in other similar work.

Keywords

• beta decay
• double-ionisation
• two-electron calculations
• Hylleraas wave functions
• Sturmian projectors