ABSOLUTE CROSS SECTIONS IN NEAR-THRESHOLD ELECTRON IMPACT EXCITATION OF THE 3s3p 1P AND 3P STATES OF S4+ AND THE 3p 2P STATE OF S5+

Inelastic electron collisions play a signicant role in the properties of many laboratory and as-trophysical plasmas. Cross sections and rate co-ecients for these processes are crucial for mod-eling and diagnosing plasmas in controlled fu-sion, plasma processing and astrophysics. The large amount of data required has been, and will continue to be, provided predominantly by theo-retical calculations with the role of experiments being the measurement of selected cross sections to serve as tests of the theoretical models. We are reporting measurements for the dipole-allowed transitions 3s2 1S! 3s3p 1P in S4+ and 3s 2S! 3p 2P in S5+ and the spin-forbidden transi-tion 3s2 1S! 3s3p 3P in S4+ as a continuation of our experimental research program