Comparative study of the collisional electron detachment of C-, Si-, and Ge- by light noble gases - art. no. 052716

Collisional electron detachment of anions with np(3) structures (n = 2, 3, and 3), namely, C-, Si-, and Ge-, was studied for He, Ne, and Ar targets an d relative velocities ranging from 0.2 a.u. to 2.2 a.u.. Single, double, an d triple electron ejection cross sections were also measured for the C- ani on colliding with an Ar target, being observed to obey a binomial distribut ion. Two striking universal features were observed concerning the total det achment cross sections: for each target a multiplicative scaling may be mad e for the cross sections of the three projectiles, and these factors are ta rget independent. The maxima of these three curves show a nonmonotonic corr espondence with the noble-gas atomic numbers. A simple law, proposed for th e scaling, indicates the presence of metastable states in the Si- and Ge- b eams.