Loosely bound states of three particles

Cold atom-atom-ion three-body recombination of 4He-4He-X- (X = H or D)

The atom-atom-ion three-body recombination (TBR) of mixed ⁴He and X^- (X = H or D) systems is investigated by solving the Schrödinger equation using the adiabatic hyperspherical representation method. It is shown that the dominant products after a TBR in the ultracold limit (E ≤ 0.1 mK × k_B) are different for the two systems. For the ⁴He⁴HeH^- system, the rate of TBR into the ⁴HeH^- ion is nearly two orders of magnitude larger than that of TBR into the neutral ⁴He₂ molecule. In contrast, the yield of ⁴He₂ is a little higher than that of ⁴HeD^- for the ⁴He⁴HeD^- system. Furthermore, since the adiabatic potentials become more attractive and the nonadiabatic couplings become much stronger by substituting D for H in the ⁴He⁴HeH^- system, the total TBR rate for the ⁴He⁴HeD^- system is nearly two orders of magnitude larger than that for the ⁴He⁴HeH^- system.