Small angle scattering from crossed sodium and potassium beams

Abstract

The small angle dependence of the differential cross-section for the elastic scattering of Na by K has been measured at relative velocities from 936 to 1420 m sec^–1 using a crossed-beam technique. Quantum undulations in the cross-sections were observed at laboratory angles less than 2° and their origin is discussed. The positions of the observed peaks together with a singlet potential obtained from spectroscopic data yield information on the long-range dispersion forces and the triplet potential. For the triplet potential with an assumed Lennard-Jones 8 : 6 from the best agreement found between observation and forward calculation yielded ε= 2 × 10^–14 ergs and r_m= 5.6 Å, though the fit is not perfect.