Knowledge Bank

The Zeeman splitting of the Doppler-free polarization spectra of the singlet-triplet perturbed levels $A1\Sigma u\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}(v=2,J=33):h3\Pi u(v=0,N=32,Fl,e)$ in $\mathrm{<mrow\; data-mjx-texclass="ORD">6</mrow>}Li2$ has been used to determine the fine structure constants for the triplet state. Measurements were made in magnetic fields up to 3 kG using a CW single mode dye laser. Orientation of the laser beam polarization with respect to the applied magnetic field gives different $mJ$ level selectivity. A fit of the Zeeman splitting pattern vs magnetic field with a Hamiltonian containing vibronic, rotational, spin-orbit, spin-spin, spin-rotation, and Zeeman terms yields the interactions responsible for the fine structure.