Permanent electric dipole moment of molybdenum carbide

High resolution optical spectroscopy has been used to study a molecular beam of molybdenum monocarbide (MoC). The Stark effect of the Re (0) and Qfe (1) branch features of the [18.6] Π13 -X -3 (0,0) band system of Mo98 C were analyzed to determine the permanent electric dipole moments μe of 2.68(2) and 6.07 (18) D for the [18.6] Π13 (=0) and X -3 (=0) states, respectively. The dipole moments are compared with the experimental value for ruthenium monocarbide [T. C. Steimle, J. Chem. Phys. 118, 2620 (2003)] and with theoretical predictions. A molecular orbital correlation diagram is used to interpret the observed and predicted trends of ground state μe values for the 4d -metal monocarbides series.