Individual orbital contribution to the electronic stopping cross section in the low-velocity region

In the spirit of Firsov's theory as modified by Brice, an exact expression for the electronic stopping cross section ($S_e$) has been evaluated using analytical Hartree-Fock-Slater wave functions. Two consequences of this treatment are that (a) the individual orbital contribution to $S_e$ is obtained, (b) an ab initio calculation of Brice's $Z$ parameter is performed. In the former case conclusions are drawn about the importance of orbitals to the evaluation of $S_e$. For the latter case a comparison is made between the exact $Z$ values and Brice's values.