Some aspects of energy transfer in molecular and atomic collisions. [Cross sections, statistical model, quenching; S matrix

Abstract

It is maintained that quenching of 0(/sup 1/D) by collision with N/sub 2/ and the ionization of Na by collision with vibrationally excited N/sub 2/ proceed via the formation of a collision complex. Once the complex is formed, even a weak coupling between the two states involved, can induce a large transition probability because the crossing seam of the two potential energy surfaces is passed many times during the life of the complex. Qualitatively reasonable potential energy surfaces for 0(/sup 1/D) + N/sub 2/ are constructed and classical trajectory calculations carried out to show that the cross section for complex formation is indeed appreciable; a statistical model is used to determine the quenching probability of the complex; results are in good agreement with experiment. Ab initio (SCF) potential energy surface calculations are carried out for N/sub 2/-Na, N/sub 2/-Na/sup +/, and N/sup -//sub 2/-Na/sup +/ systems; the points are fit to simple standard functions; a statistical model is developed for the ionization of Na by vibrationally excited N/sub 2/. The classical S-Matrix theory is applied to rotational excitation of CO by collision with He; the results are in qualitative agreement with quantum mechanical calculation.