Fine-structure state-dependent reactivity of Kr+(2Pj) with O2, CO, N2O and OCS from 0.04 to several eV collision energy

The separate reactions of the 2 P 3/2 and 2 P 1/2 ground states of Kr + with O 2 , CO, N 2 O and OCS have been investigated over the mean relative kinetic energy (E cm ) range from 0.04 to several eV using a flow-drift tube (FDT) apparatus. The versatility of the technique has permitted state selective ion generation and depletion. Charge transfer has been observed from Kr + ( 2 P 3/2 ) and Kr + ( 2 P 1/2 ) to each neutral reactant with rate coefficients k and k* respectively. Although not previously observed at 300K, collisional Kr + ( 2 P 1/2 ) to Kr + ( 2 P 3/2 ) conversion (quenching) with the neutral reactant is taken into account, since this process can become significant at higher energies, as is demonstrated here in reactions with N 2 O. This is described by a rate coefficient k q . Experiments with CO suggested the reverse process of collisional conversion Kr + ( 2 P 3/2 ) to Kr + ( 2 P 1/2 ) also takes place above the necessary energy threshold. Experimental result (for the reactants shown) are presented for k(O 2 , N 2 O and OCS), k* (OCS) and k t (N 2 O, O 2 and OCS, where k*