Spin-Rotation Coupling in the Alkali—Rare-Gas Van der Waals Molecule KAr

Abstract
We report results of a molecular-beam magnetic-resonance study of the paramagnetic Van der Waals molecule KAr. The experiment yields a value for the spin-rotation interaction γS·N, where S and N are, respectively, the electronic and rotational angular momentum. The average spin-rotation constant in KAr is γ¯=0.24(1) MHz.