ELECTRON-IMPACT EXCITATION OF THE A-(3)PI, A'-(3)SIGMA(-(3)DELTA AND A-(1)PI STATES OF CO AT 10.0, 12.5 AND 15.0 EV IMPACT ENERGIES(), D)

We have measured the differential and integral cross sections for elec tron impact excitation of the a(3) Pi, a'(3) Sigma(+), d(3) Delta and A(1) Pi states of CO in the 10-15 eV impact energy region. These measu rements fill the gap which existed between the low-energy (threshold t o about 12 eV) data of Zobel et al and the intermediate energy (20-50 eV) results of Middleton et ctl. Recent electron time-of-flight measur ements are utilized to place the relative cross sections (deduced from energy-loss spectral on the absolute scale. The cross sections are in excellent agreement viith the results obtained by Zobel et al at the overlapping impact energies and always smoothly extrapolate to their l ow-energy results. Extrapolation to the intermediate energy domain and comparison with the results of Middleton et al is not so clear. Compa rison with theoretical differential and integral cross sections of Sun et al and the integral cross sections of Morgan and Tennyson reveals angular and energy dependences which resemble those found for the expe rimental results but there are serious discrepances concerning the abs olute magnitudes.