FURTHER MEASUREMENTS OF ANISOTROPY OF MOLECULAR INTERACTION BY SCATTERING OF MOLECULES IN DEFINED QUANTUM STATES .3. DETERMINATION OF ANISOTROPY FACTOR IN REPULSIVE INTERACTION OF CSF WITH HE

The interaction between diatomic molecules and rare gas atoms can be described by the realistic, though simplified potential V=e{open}[(rm/r)12(1 +q12P2(cos θ))-2(rm/r)6(1+q6P2(cos θ))] The determination of the parameters e{open}, rmand q6has been treated in the two previous parts of this series. The present final paper describes the determination of the anisotropy parameter in the repulsive part of the potential, q12, for the system CsF-He. While q6 could be derived using only the dependence of the total scattering cross section on the molecular rotational state, the determination of q12 requires, in addition, knowledge of the velocity dependence. The comparison of the experimental data for CsF in the rotational states |J, M〉=|1, 1〉 and |1, 0〉 with cross sections calculated by means of the high energy" approximation yields the result:q12=0.9±0.2. The validity of the "high energy" approximation in the velocity range covered by the experiment is discussed. © 1969 Springer-Verlag."