Knowledge Bank

It has been known for many $years1$ that the (000) level of the $B¯2\Sigma u+$ state of the $Co2+$ ion is severely perturbed at low values of $J.Emission2$ and laser excitation $spectra3$ with low rotational temperatures have given low. J rotational term values for the e and f components of the $B¯(000)$ state and of two perturbing states. The present work is concerned with rotational analyses of new emission spectra at rotational temperatures of about 40 K and 200 K from the perturbed $B¯(000)$ state to high levels (up to $10000cm-1)$ of the ground state. These bands, whose intensity is due to the perturbing states, are shown to be parallel bands to $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +g$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma -g$ vibronic levels with odd values of the vibrational quanturm numbers $\nu 2$ and $\nu 3$ in the ground $X¯2\Pi$g electronic state. The states perturbing the $B¯(000)$ state, which must therefore be one $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma u+$ state and one $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma -g$ state, are assigned to the vibronic levels $A¯(231)\mu 2\Sigma u+$ and $A¯(151)\kappa 2\Sigma u-$ of the $A¯2\Pi u$ electronic state. Improved vibronic parameters for the $X¯2\Pi g$ and $A¯2\Pi u$ electronic states are obtained.