Spinaustauschstreuung von Kalium an Caesium

The differential spin exchange cross sectionI _ex(?, E) for the system K-Cs has been measured as a function of angle for 2°???40° and collision energy for 1.2 · 10^?13 erg ?E?2.1 · 10^?13erg. Confirming previous experiments it exhibits a maximum neargj≈10°. The angular position of maximum changes with collision energy. Increasing the energy lowers the maximum angle. The analysis of the cross section with regard to information about the interaction of the collision partners turns out to be very complicated. A first few model calculations are presented and discussed. The most obvious, qualitative relations between the singlet and triplet interaction potentials,V ₀ andV ₁, and the differential spin exchange cross sectionI _ex(?) appear to be: 1. The average magnitude ofI _ex is markedly different below and above the rainbow angle \(\vartheta _{R_1 }\) of the shallow triplet potential V₁. From the observed intensity drop towards large angles we estimate a lower bound for the triplet potential well depth? ₁?1.4 · 10^?14 erg. 2. The expected relation between the integral spin exchange cross sectionσ _ex and the difference potentialΔV(R)=V ₁-V ₀ at large distances is also borne out by the differential spin exchange cross section I_ex(?) below \(\vartheta _{R_1 }\) . Relative to the intensity beyond \(\vartheta _{R_1 }\) the cross section increases if range and strength ofΔV is increased.