Molecular-beam magnetic-resonance measurement of the spin-rotational interaction in RbKr

Abstract

We have investigated the spin-rotation interaction in the van der Waals molecule RbKr using molecular-beam magnetic-resonance techniques. The bound $^{2}\ensuremath{\Sigma}$ molecules were produced in an expansion-cooled molecular beam and the interaction between the electronic spin angular momentum ($\ensuremath{\hbar}\stackrel{\ensuremath{\rightarrow}}{\mathrm{S}}$) of the rubidium valence electron and the rotational angular momentum ($\ensuremath{\hbar}\stackrel{\ensuremath{\rightarrow}}{\mathrm{N}}$) of the molecule was probed by magnetic resonance. A value for the strength of the interaction and a model of its dependence upon the internuclear separation were obtained. Results of numerical calculations of all bound and quasibound vibrational-rotational states of the RbKr ground-state potential are presented. These wave functions permit a detailed comparison of the results obtained by this technique and those obtained by M. Bouchiat et al. using optical-pumping techniques in a high-temperature gas cell. Excellent agreement is obtained when all of the relevant molecular states are considered.