Perturbations of the A 1Σ+u and b 3Πu states of Na2 and the effects on the transition intensity and the line splitting

Doppler-free polarization spectra of the A 1Σ+u (v=8, J=0–15) and b 3Π0u (v=14, J=0–15) states were observed. By analyzing the energy shifts, the spin–orbit interaction between the A 1Σ+u (v=8) and b 3Π0u (v=14) states was studied. The magnitudes of the hyperfine splittings were different in corresponding lines of the two states. In addition to the energy shifts, the line intensities and the line shapes were found to change remarkably near the perturbation. These are useful to study the mixing of the perturbing states.