Identification of two new excited electronic states of NiCl: Analyses of the (1,0) & (0,0) bands of the [13.5] 2 Φ 7/2 – [0.16] A 2 Δ 5/2 and (0,0) band of the [13.8] 2 Π 1/2 – [0.38] X 2 Π 1/2 transitions

The near-infrared spectrum of NiCl has been recorded at high resolution in the 13,200–13,500 cm −1  and 13,600–13,750 cm −1  regions using Intracavity Laser Spectroscopy (ILS). The NiCl molecules were produced in the plasma discharge of a Ni-lined copper hollow cathode with 0.3–0.6 torr of argon as the sputter gas, and a trace amount of CCl 4 . Several electronic transitions were observed, including three transitions involving two previously unreported excited electronic states. The (0,0) and (1,0) bands of the [13.5]  2 Φ 7/2  – [0.16]  A   2 Δ 5/2  transition were observed near 13,318 cm −1  and 13,709 cm −1 , respectively. The (0,0) band of the [13.8]  2 Π 1/2  – [0.38]  X  2 Π 1/2  transition was observed near 13,480 cm −1 . With analysis of these transitions, molecular constants have been obtained for eleven of the twelve predicted NiCl doublets states with term energies less than 16,000 cm −1 . Comparison of experimentally observed transitions with the theoretical work is presented.