Electron detachment of Si- by He, Ne, and Ar - art. no. 022705

The cross sections for electron detachment of Si- were measured for He, Ne, and Ar targets at relative velocities in the 0.25-1.4 a.u. range. Argon ta rget cross sections were measured using Si- ions from two different origins , the results agreeing well with each other and with literature values. The velocity dependence of the Si- cross sections is strikingly similar to tha t of known H- results, with the former being consistently larger than the l atter and, at large velocities, differing by a multiplicative constant.