We have studied spin-orbit perturbations between the A (2) 'E+ and 6(1) 3110 states of the NaK molecule by accurately measuring the energies of mutually perturbing levels, and by measuring ratios of A (2) 'Zf -+ X(1) '8+ and b(1) 3110 + a(1) 32+ emission intensities, for five perturbed pairs. This allows twz partially independent determinations of each perturbation matrix element I(1 3110(ui,JI)
... [Show full abstract] 1 H, ]2'2+ (r&J')) 1. From these matrix elements, and calculated vibrational overlap inmgrals (u: 1 vi), the electronic part of theperturbationmatrixelement, H,1~~(13~,(v~,J')~H,,~2'2+(v~,J'))I/I(vjIv~)~, was obtained. Our results for He, from the two methods are consistent, and independent of vibrational and rotational quantum numbers, as expected. The determined best value for H,, is (15.64=tO.39) cm-'.