Abstract
The absolute total scattering cross sections for K-N2 and K-CO were measured by the atomic beam attenuation method with velocity-selected potassium beams. Care was taken of the mercury drag effect in pressure measurements of N2 and CO. The effective length of the scattering chamber was obtained experimentally by changing the length of the chamber. Corrections for the thermal motion of the target gas and the angular resolution were estimated with the Barkling et al.'s formula and von Busch's formula, respectively. It is confirmed that even in the atom-diatomic molecule system van der Waals forces are dominant for scattering at thermal energies, and van der Waals constants are 325×10-60 erg·cm6 for K-N2 and 328×10-60 erg·cm6 for K-CO. These values are compared with other experimental and theoretical ones and are in agreement with the theoretical results of Langhoff and Karplus within the limit of errors.
