Bond-forming and electron-transfer reactivity between Ar2+ and N2

Collisions between Ar2+ and N-2 have been studied using a coincidence technique at a centre-of-mass (CM) collision energy of 5.1 eV. Four reaction channels generating pairs of monocations are observed: Ar+ + N-2(+), Ar+ + N+, ArN+ + N+ and N+ + N+. The formation of Ar+ + N-2(+) is the most intense channel, displaying forward scattering but with a marked tail to higher scattering angles. This scattering, and other dynamics data, is indicative of direct electron transfer competing with a 'sticky' collision between the Ar2+ and N-2 reactants. Here Ar+ is generated in its ground (P-2) state and N-2(+) is primarily in the low vibrational levels of the C-2 sigma(+)(u) state. A minor channel involving the initial population of higher energy N-2(+) states, lying above the dissociation asymptote to N+ + N, which fluoresce to stable states of N-2(+) is also identified. The formation of Ar+ + N+ by dissociative single electron transfer again reveals the involvement of two different pathways for the initial electron transfer (direct or complexation). This reaction pathway predominantly involves excited states of Ar2+ (D-1 and S-1) populating N-2(+)* in its dissociative C-2 sigma(+)(u), 2(2)pi(g) and D-2 pi(g) states. Formation of ArN+ + N+ proceeds via a direct mechanism. The ArN+ is formed, with significant vibrational excitation, in its ground (X-3 sigma(-)) state. Formation of N+ + N+ is also observed as a consequence of double electron transfer forming N-2(2+). The exoergicity of the subsequent N-2(2+) dissociation reveals the population of the A(1)pi(u) and D-3 pi(g) dication states.

Automated summary

Collisions between Ar2+ and N-2 were studied at a collision energy of 5.1 eV, revealing four reaction channels and the competition between direct electron transfer and 'sticky' collisions. Forward scattering with a marked tail to higher angles was observed, indicating complex dynamics between the reactants.