A theoretical study of NiH Optical spectrum and potential curves

Abstract
Potential curves for the three lowest states of NiH, 2Δ, 2Π and 2Σ+, were calculated at both the CASSCF and the multireference CI level For the 2Δ ground state the bond distance, 1·470 Å, and the ΔG 1/2 value, 1911 cm−1, obtained at the CI level agree very well with the experimentally observed values, 1·475 Å and 1927 cm−1 respectively. A large part of the optical spectrum of NiH was also calculated at the CI level. It is concluded that there is only one excited 2Δ state at 15 000 cm−1, in contradiction to the earlier experimental assignment of two 2Δ states in this region.