Ion-neutral collisions in a 22-pole trap at very low energies

This contribution concentrates on the use of an ion trapping technique which has been developed for studying collision processes and chemical reactions at low temperatures and which utilizes inhomogeneous radio frequency fields. Special emphasis is put onto recent progress achieved with a cryo cooled 22-pole ion trap. Experimental results, measured at a nominal temperature of 10 K, are presented for radiative association of CH 3 + and C 2 H 2 + with H 2 . Another group of results discussed in this paper deals with the dynamics of the growth of hydrogen clusters starting from H 3 + . In all cases, the influence of H 2 rotation was examined by utilizing p-H 2 and n-H 2 . Also the process of isotope fractionation in the presence of HD and D 2 is briefly mentioned.