Knowledge Bank

Laser-induced fluorescence of NiO formed by the reaction of sputtered Ni atoms from a hollow cathode source with oxygen or ozone was studied. Some of the bands belonging to the Rosen's System $IV1$ were vibrationally and rotationally analyzed. A new vibrational assignment is proposed. The rotational structure of the strongest band at 5176.5 {\AA} resembles $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Pi -1\Pi$ or $\Omega \prime =1$ to $\Omega \prime \prime =1$ transition. Interesting features include a rotational perturbation in the excited state and extremely strong $\Omega$-doubling in the lower state. This suggests the presence of nearly degenerate $\Omega =0$ electronic state which could be another component of a $a3\Sigma -$ state in Hund's coupling case c. Preliminary rotational analysis of the 5176.5 {\AA} band gives $r\prime =1.73$ {\AA} and $rv\prime \prime =1.62$ {\AA} for the equilibrium distances in the upper and lower electronic states.