Dynamical study of competing reactions in the CN −-H 2 collisional system by a multicoincident detection

Abstract

A dynamical investigation of the competing reactions involved in CN −-H 2 collisions is performed in a crossed beam experiment with a multicoincidence detection of fast neutrals and ionic products for energy ranging from 2 to 18 eV. Doubly differential cross sections are presented in form of velocity contour maps for both H − and e − production. At high energy a common mechanism is proposed in which a first N-H binary collision is followed by a rearrangement of the two others partners. At lower energy, a long-lived complex should be responsible for the reactive detachment channel. This complex would correspond to the formation of the stable molecule H 2C=N. For the mechanism involving a complex formation, the translational energy distribution of the neutral products agrees with a statistical partitioning of the energy involving, as a constraint, a frozen CN bond.