NEGATIVE-ION FORMATION BY ELECTRON-ATTACHMENT IN S-2 AND IN THE SULFUR VAPOR

Dissociative electron attachment in effusive beams of S-2 has been stu died in the incident electron energy range 0-11 eV. Two S- processes a re observed at 2.4 and around 4.55 eV. From the ion kinetic energy and angular distributions, the symmetries of the dissociative S-2(-) reso nant states have been determined as (4) Sigma(u)(-) and (2) Pi(u). In the sulphur vapour S-n (2 less than or equal to n less than or equal t o 8), S-n(-) formation occurs at zero energy and around 4 and 7.5 eV, in addition to the S-/S-2 processes.