First-ordex' many-body theory has been used to calculate the differential and integral cross sections for electron-impact excitation of all the 3s, 3s' levels, and certain of the 3p, 3p' levels of neon, fox' incident electron enex'gies ranging from 20 to 120 eV. The x'esulting differential cross sections foI' thc excitation of thc optically allo&cd Pl and thc Pl lcvcls sholv, foI thc 10 484 80 Rngular range, a discrepancy no gx'eatex than 15% when compared vrith x'ecent expeximental results, except fol very fcw points. Spin-orbit coupling &as included in thc Xvave fuQctions and its cffcct on dctclminlng thc diffclcntial cross sections foI thc I l lcvcl %'Rs found to bc very importRQt foI scattering angles less than 40'. For the differential cross sections of the other 3s, 3s' levels the discx'epancy in the 30'&8& 80' x'ange is only slightly larger than the experimental erx'ors. For the 3p, 3p' levels considered here, ere have found strong disagreement mth experimental data and there Is also substantial disagrccmcnt among thc vanous thcorctical I'csults. Is interesting to note though that thc f11st reported calculation for the electron-impact excitation of the unresolved 3s, 3s' levels of neon by Massey and Mohr " was with the distorted-wave approximation with thc additional slmpli" fication that the asymptotic form of the distorted waves were Used and the partial-wave phase shifts were calculated using Jeffrey's (also called &KB) approximation.

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We report calculated differential and integral cross sections for e-C,H, collisions in the 10-200 eV energy range. These cross sections were derived from fixed-nuclei scattering amplitudes in such a way that the low angular momentum components are obtained using the Schwinger iterative method and the large ones are treated by a Born closure. Using this combined theory, it can be shown that the elastic differential cross sections obtained at the static-exchange level are nearly exact, even at higher energies. The inclusion of a semi-empirical polarization potential is discussed as well.

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