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 × kB) 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.