Single vibronic level emission spectroscopy of the low-lying electronic states of NiI

Five low-lying (Te < 2200 cm ) electronic states of NiI have been observed using single vibronic level (SVL) emission spectroscopy, via three hitherto unobserved band systems in the range 21 150– 22 410 cm . In addition to the previously characterized XD5/2 and A P3=2 states, the X D3=2, A P1=2, and BR1=2 states have been observed for the first time. The emission spectra yield term energies and vibrational constants that are in excellent agreement with recent ab initio calculations. A number of perturbations in the vibrational level structure can be identified and are attributed to homogenous interactions under the selection rule DX = 0. 2010 Elsevier B.V. All rights reserved.