Crossed-beam study of the reactions H3+(Ar,H2)ArH+ and ArH+(H2,Ar)H3+

Abstract
The dynamics of the reactions H3+(Ar,H2)ArH+ and ArH+(H2,Ar)H3+ were studied over the initial relative translational energy from 0.87 to 9.7 eV and from 0.18 to 6.7 eV, respectively. The reactions were found to proceed via direct mechanisms at all energies studied. Energetic data are presented that suggest H3+ is not rapidly relaxed vibrationally upon collision with H2 as previously thought. Rather than being relaxed within a few collisions, the lower vibrational states probably are relaxed with a rate constant on the order of 10−12 cm3 molecule−1⋅sec−1.