FARADAY LMR SPECTROSCOPY OF THE MGO A(1)PI-X(1)SIGMA-2) AND A(3)PI(0,1)-X(1)SIGMA+ (0-1) BANDS( (0)

We report the first direct observation of transitions between the stro ngly mixed low lying X1SIGMA+, a3PI and A1PI electronic states of (MgO )-Mg-24-O-16. The A1PI-X1SIGMA+ (0-2) band and the a3PI0.1-X1SIGMA+ (0 -1) intercombination bands have been detected. The measurements were p erformed with the CO laser Faraday laser magnetic resonance (LMR) tech nique in combination with a special oven set-up for the MgO production . The LMR data were fitted together with already published data to an effective Hamiltonian where the spin-orbit, orbit-rotation and Zeeman interactions between these three electronic states are included direct ly. We determined the interaction parameters and obtained a set of eff ective deperturbed molecular parameters of MgO in the X1SIGMA+ (v = 0, 1, 2), a3PI (v = 0) and A1PI (v = 0) states. These parameters describ e the LMR data within 7 x 10(-4) cm-1 (21 MHz) on average, which corre sponds to the experimental uncertainty.