Fragmentation branching ratios of highly excited hydrocarbon molecules CnH and their cations CnH+ (n Tuna, T; Chabot, M; Pino, T; Désesquelles, P; LePadellec, A; Martinet, G; Barat, M; Lucas, B; Mezdari, F; Montagnon, L; Van-Oanh, N T; Lavergne, L; Lachaize, A; Carpentier, Y; Béroff, K. Afiliación Tuna T; Institut de Physique Nucléaire, CNRS-IN2P3 and Université Paris-Sud, 91405 Orsay Cedex, France. J Chem Phys ; 128(12): 124312, 2008 Mar 28. Article en En | MEDLINE | ID: mdl-18376924

ABSTRACT

We have measured fragmentation branching ratios of neutral C(n)H and C(n)H(+) cations produced in high velocity (4.5 a.u) collisions between incident C(n)H(+) cations and helium atoms. Electron capture gives rise to excited neutral species C(n)H and electronic excitation to excited cations C(n)H(+). Thanks to a dedicated setup, based on coincident detection of all fragments, the dissociations of the neutral and cationic parents were recorded separately and in a complete way. For the fragmentation of C(n)H, the H-loss channel is found to be dominant, as already observed by other authors. By contrast, the H-loss and C-loss channels equally dominate the two-fragment break up of C(n)H(+) species. For these cations, we provide the first fragmentation data (n>2). Results are also discussed in the context of astrochemistry.