Knowledge Bank

The laser-induced fluorescence spectrum of CrO was recorded at Doppler-limited resolution in the near-infrared employing a single-frequency tunable cw Ti:sapphire ring laser. The (O,O) band centred near 8400 {\AA} consists of five unperturbed sub-bands each characterized by readily identifiable P, Q, and R branches. Rotational analysis confirmed the nature of the excited state of the red system of CrO as $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta$ in accord with a recent low-resolution $study1$. Spectroscopic measurements from the present analysis were combined with those of the $A5\Sigma +-X5\Pi$ (0,0) transition recorded previously using an FTIR $spectrometer2$. A weighted nonlinear least-squares fit furnished improved molecular parameters for the $A5\Sigma +$ and $X5\Pi$ electronic states as well as the first set of reliable constants for the $A5\Delta$ state.