Knowledge Bank

A high resolution optical Stark spectroscopic study of the $(0,0)A4\Pi 3/2-X4\Sigma 1/2$ band system of molybdenum mononitride, MoN, has been performed. A supersonic molecular beam sample was produced by skimming the products of a laser ablation (355nm, 5 mJ/pulse, 20 Hz)/reaction (5% $NH3/Ar$) source. The spectra were recorded at a resolution of 50 MHz (FWHM) and in the presence of a static electric field of up to 3.5 kV/cm. Permanent electric dipole moments of 4.56(9)D and 3.38(7)D were determined for the $A4\Pi$ and $X4\Sigma -$ states, respectively. These values agree well with the only theoretical $prediction1$. The field free spectra for the $\mathrm{<mrow\; data-mjx-texclass="ORD">95</mrow>}MoN$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">97</mrow>}MoN$ isotopic forms exhibit a large splitting which has been interpreted as arising from the magnetic hyperfine interaction in the $X\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ state. The resulting Fermi contact parameter, $bF$, is of the same magnitude but opposite sign as the previous matrix isolated ESR $determination2$.