CALCULATIONS OF SPIN-EXCHANGE CROSS SECTIONS OF ALKALI ATOMS BY PARTIAL-WAVE ANALYSIS

Four different spin-dependent scattering cross sections are calculated by semiclassical and by partial-wave analyses for each of the five alkali atoms, Li, Na, K, Rb, and Cs, for 124 different relative kinetic energies. These cross sections are finally averaged thermally. The results agree very well with experiments. In the calculation, the interaction potential between two alkali atoms is calculated by individually considering the interaction due to the two valence s electrons and to the closed electronic shells of the two atoms. The two-s-electron interaction is generated ad hoc phenomenologically from the known hydrogen-hydrogen interatomic potential and the closed-shell interaction from interatomic potentials of two inert atoms corresponding to the cores. The potentials so obtained are in agreement with those constructed from band spectra. © 1969 The American Physical Society.