Knowledge Bank

The near infrared electronic transition of CuCl occuring in the region of $13,500cm-1$ has been recorded by intracavity laser absorption spectroscopy. The CuCl molecules were produced in a copper hollow cathode operating with an applied potential of 700 V, using 1.4 torr argon and a trace amount of carbon tetrachloride. The near infrared transition previously was recorded by Balfour and $Ram,a$ and it was assigned as emission from a low-lying $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma +$ state to the $X1\Sigma +$ state. Recently, this transition has received considerable attention because of high level ab initio $calculationsb$ that question whether this transition involves the $X1\Sigma 1$ ground state.