Knowledge Bank

Recently we $reported1$ the results of a high resolution optical Stark spectroscopic study of the $(0,0,0)-(0,0,0)A\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi -X2\Sigma$ band system of calcium isocyanide, CaNC. Although the optical spectra could be reduced using a conventional effective Hamiltonian operator, the spectroscopic parameters for the ``'' state were physically unrealistic. Specifically, $B\ast -B\prime$ was too large, , and the A-doubling parameters were too large. It was postulated that these effects were a result of large Renner-Teller effects and/or a mis-assignment of the excited state. Here we report on the results of the rotational analysis of the $Ca15NC$ and $CaN13C$ isotopic forms. Similar to previous $studies1,2$, a supersonic molecular beam sample was produced by skimming the products of a laser ablation (355nm, 5 mJ/pulse, 20 Hz)/ reaction $(5\%CH3CN/Ar)$ source. The spectra were recorded at a resolution of 50 MHz (FWHM). The $X2\Sigma$ state data fits to a standard model and produces bond lengths of: Ca-N, .227(9) nm; N-C, .115(9)nm. At the time of this submittal it has been impossible to get a satisfactory reduction of the excited state eigenvalues for the $Ca14N12C,Ca15NC$ and $CaN13C$ isotopic forms.