Differential and integral cross sections for rotational/vibrational transition in N2 colliding with Li+ have been calculated using a semiclassical collision model. The potential energy surface used was an analytical 19-parameter fit to 95 ab initio SCF points. Comparison with values obtained experimentallyn and by classical trajectory calculations has been made. We shall finally summarize the important results of the present semiclassical calculations. 1. (1)An analytical potential surface containing just 19 parameters have been obtained using non-linear least-squares fitting technique. The root mean square deviation from 95 SCF points is about 6.6%. 2. (2)By introducing a state expansion in the vibrational states better statistics have been obtained for the weak rotational-vibrational transitions. 3. (3)The differential cross sections as a function of the final rotational state show a distribution with a single peak. This is in agreement with classical trajectory studies by Thomas [4] and experimental findings [6]. 4. (4)The distribution mentioned above is slightly narrower than the one found experimentally, especially at 7.07 eV. 5. (5)Since these calculations which include a P4 term in the potential agree (within the error bars) with the classical trajectory calculations which include a P6 term [4], one would tend to believe that the calculations have converged witt respect to the Pn expansion. Thus agreement between theory and experiment should be improved by improving the P0, P2 and P4 terms. 6. (6)The total energy transfer calculated using the present surface and method is in very good agreement with experimental findings. 7. (7)The calculations show more vibrational excitation than was resolved experimentally [6]. At 4.23 eV the vibrational inelastic cross sections are about 10% and at 7.07 eV about 30% of the vibrational elastic cross sections. 8. (8)The distribution of the differential cross sections on final rotational states is slightly narrower for the vibrational inelastic transitions than for the vibrational elastic transitions. The peaks of the two distributions are, however, located at about the same value of the final rotational angular momentum. © 1979.
