Abstract
A modulated retarding-potential-difference technique has been used to define the energy width of an electron beam located in the source region of a time-of-flight mass spectrometer. Negative ions with energies in the region 0-3 eV are produced by dissociative electron attachment to gas molecules in this source and are permitted to react for a controlled continuously variable length of time with neutral molecules to produce secondary negative-ion products. From the observed time development of the reactions, the reaction rate constant may be obtained, and the cross section then calculated if the primary-ion velocity is known. Results are presented for the reactions + → + O, + O → + , and + O → + at a number of primary ion energies, and for the reactions + O → + NO, + S → S + (HCOOF), and S + HCl → + (SH) at single energy points.
- Received 28 April 1969
DOI:https://doi.org/10.1103/PhysRev.184.81
©1969 American Physical Society