A series of experiments was conducted in which trimethylbismuthine (TMB) was used to introduce atomic bismuth into a supersonic flow of electronically excited nitrogen fluoride, NF(a1Δ), at an elevated density of 3 x 1015 mol cm-3. Excited-state densities of Bi(2D) approximately equal to 1 x 1013 atom cm-3 and BiF(AO+) approximately equal to 4 x 1O11 mol cm-3 were achieved. After correction for mixing, these density values agreed reasonably well with values predicted by a quadratic scaling law. Simulation of the blue BiF(AO+)-BiF(XO+) emission spectrum suggests that the BiF(AO+) was in vibrational as well as rotational equilibrium at 300°C. The significance of these results for developing a supersonic BiF(AO+) laser utilizing TMB is discussed.