Two-channel dissociation of chemically and thermally activated n-butylbenzene cations (C10H14+).

The charge-transfer reaction O(2)(+) + n-butylbenzene (C(10)H(14)) --> O(2) + C(10)H(14)(+) was studied in a turbulent ion flow tube at temperatures between 423 and 548 K and pressures between 15 and 250 Torr in the buffer gases He and N(2). Under chemical activation conditions stabilization vs dissociation ratios S/D of vibrationally highly excited C(10)H(14)(+)* as well as branching ratios of the fragments C(7)H(7)(+) (m/z = 91) vs C(7)H(8)(+) (m/z = 92) of the dissociation of C(10)H(14)(+)* were measured. Under thermal activation conditions, the rate constant of the dominating dissociation channel 92 was measured at 498 and 523 K.

Ion-molecule kinetics at 15-700 Torr.

Studies of ion-molecule chemistry are usually made at pressures of a few Torr and below. By contrast, there are numerous plasmas that occur at higher pressures. For that reason we have constructed a turbulent ion flow tube (TIFT) for studying ion-molecule kinetics from 15 to 700 Torr.

Ion-molecule rate constants and branching ratios for the reaction of N(3) (+)+O(2) from 120 to 1400 K.

The kinetics of the reaction of N(3) (+) with O(2) has been studied from 120 to 1400 K using both a selected ion flow tube and high-temperature flowing afterglow. The rate constant decreases from 120 K to approximately 1200 K and then increases slightly up to the maximum temperature studied, 1400 K. The rate constant compares well to most of the previous measurements in the overlapping temperature range.