The low-pressure association reactions for the proton bound dimers of acetone and a number of deuterium substituted variants have been studied using Fourier transform ion cyclotron resonance spectrometry. The association rate constants for the reactions (CH3)(2)COH+ + (CH3)(2)CO, (CH3)(2)COD+ + (CH3)(2)CO, (CD3)(2)COH+ + (CD3)(2)CO, and (CD3)(2)COD+ + (CD3)(2)CO have been studied as a function of pressure, and from these data the unimolecular dissociation rate constants, k(b), of the intermediate chemically activated adducts as well as their radiative cooling rates, k(ra), were derived. The k(b) were measured to be in the range of(1.49-4.9) x 10(4) s(-1) at 47 degrees C, corresponding to adduct lifetimes of 20-67 mu s. These lifetimes were strongly dependent on deuterium labeling of the acetone. The radiative rate constants, k(ra), vary between 96 and 147 s(-1) with little influence of the deuterium labeling in the methyl groups, but a significant dependence when the dimer is bridged by H+ vs D+. A decrease in the temperature of the ion cyclotron resonance cell by about 20 degrees C results in a decrease in k(b) by about a factor of 2 with only a slight decrease in k(ra). These results are discussed in terms of RRKM theory, statistical thermodynamics, and the mechanism of spontaneous emission of radiation from chemically activated ions.