An experimental estimate of the O+-O resonant charge transfer cross section, collision frequency, and energy transfer rate

The resonant charge transfer cross section Q0+0 dominates the interaction between neutral and ionized atomic oxygen at temperatures greater than several hundred degrees Kelvin. This cross section is of direct importance to F region studies of ion diffusion, ion thermal balance, and neutral atmospheric winds and pressure gradients, since it determines collision frequencies and energy and momentum transfer rates. However, the uncertainty in this cross section is roughly 25--40%. Incoherent scatter measurements allow the determination of the product n0 x Q-bar0+0, the atomic oxygen concentration multiplied by the cross section. If present-day atmospheric models are accepted as statistically representative of F region n0, experimental (aeronomical) data presented here indicate that Q0+0 is about 1.3 times greater than the value presently in general use, though in excellent agreement with the only other available (laboratory) experimental value. This revised cross section has obvious implications for thermospheric studies