An interesting observation
H2+ + O2+
Note that
=  0.32 0.02  ~  1/3
H2+ + O+
while
Ne3+
=  0.390 0.006
Ne2+
Ar3+
=  0.326 0.003
Ar2+
CO3+
=  0.35 0.02
CO2+
BR seems to be a
constant fraction of H2Oq+
Heber et al. Phys. Rev. A 52, 4578 (1995)
Ben-Itzhak et al. Phys. Rev. A 47, 2827 (1993)