Linear momentum transfer effects in molecular dissociation produced by electron impact

Dissociative processes in molecules excited by electron impact can be studied by examining the angular distributions of dissociation fragments. Previous theoretical calculations of angular distributions have not included the effects of linear momentum transfer in the collision process. Such effects can be significant. A procedure, valid near threshold, is developed which permits the calculation of laboratory angular and velocity distributions. The results are applied with some success to dissociative ionization in molecular hydrogen.