Temperature dependence of the atomic three-body association reaction Ar+ + 2Ar .fwdarw. Ar2+ + Ar below 3 K

Abstract

Absolute termolecular association rate coefficients for the reaction Ar{sup +} + 2Ar {yields} Ar{sub 2}{sup +} + Ar were measured at translational temperatures between 0.5 and 3 K by using the free jet flow rector technique. The values of k{sub 3} are found to be strongly temperature dependent and fit an inverse temperature rate law, k{sub 3} = 9.52 {times} 10{sup {minus}29}T{sup {minus}1.1} cm{sup 6} s{sup {minus}1}, incorporating data between 0.5 and 300 K. There is some evidence that this fit is dominated by the low-temperature limiting behavior and that the strict T{sup {minus}n} dependence with a constant value of n is currently unjustified for atomic ion-atom association processes.