Effects of an external magnetic field on laser-induced fluorescence and photodissociation of NaK

Each line of the fluorescence to the a 3Σ+ state following the excitation D 1Π (v′=12, J′=14) ← X 1Σ+(v″=0, J″=14) of the NaK molecule is found to split into three lines when an external magnetic field is applied. The changes of the intensity and the energy splitting are measured as a function of the field strength. Formulas for the intensities of the Zeeman lines of the resonance fluorescence to the 3Σ+ state following the Q excitation 1Π(v, J M±1) ← 1Σ+ (v0,J M) are presented. The contamination of the lower triplet state a 3Σ+ by a singlet perturber X 1Σ+ is shown to be negligible from the observed Zeeman splitting and a theoretical calculation. Intensity asymmetries of the three lines split by the Zeeman effect are observed and are explained by M dependent excitation to the Zeeman components of the D 1Π state. The intensities of emission from the dissociated Na(3 2P3/2), Na(3 2P1/2), K(42P3/2), and K(4 2P1/2) are found to change remarkably when a magnetic field is applied, and each line is found to change differently from others depending on the field strength.