Knowledge Bank

“The emission spectrum in the region 5650-6600\AA, previously attributed to the A1C molecule, has been obtained with sufficient resolution to perform rotational analyses on the (0-0), (0-1), and (1-0) bands. From the magnitudes of the rotational constants and the observation of alternation of intensity, the spectrum can definitely be assigned to the $Al2$ molecule. The transition appears to be $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma -3\Sigma$, with the lower state being either $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma g-$ or $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma u+$. The following constants ($cm-1$) are reported:”