HYPERFINE-STRUCTURE OF THE NAK-C3-SIGMA+ STATE AND THE EFFECTS OF PERTURBATION

Scanning the frequency of a single-mode dye laser crossed with a molecular beam of NaK, we have measured the excitation spectrum by monitoring selectively the fluorescence intensity of transition to the a (3)SIGMA+ state. The B (1)PI(upsilon = 8) and (3)SIGMA+ (upsilon = 22) levels are perturbed around J = 5 and the c (3)SIGMA+ (upsilon = 22) and b (3)PI(upsilon almost-equal-to 62) levels are perturbed around J = 24. The transition lines to the perturbed levels are fully resolved. The hyperfine splitting, which is induced by the coupling with the nuclear spins of the Na and K atoms, is observed for levels of the c (3)SIGMA+ state and the perturbed states. The magnitude of the hyperfine splitting, the line intensity, and the energy shift are analyzed, and their relation with the perturbation is studied. The ratio of electron spin densities at the sodium and potassium atoms in the c (3)SIGMA+ state is estimated to be 0.71:0.15 from the magnitudes of hyperfine splitting.