Zeeman spectroscopy of NiH: Landé factors of three Ω = 3/2 excited electronic states

Abstract We report molecular Lande factors for three Ω′ = 3/2 vibronic levels of NiH: E[17.8], D[17.6], and I[17.2], lying 17 000–18 000 cm −1 above the ground electronic state. The molecular Lande factors of these three states exhibit unusual variations with J and with parity. Also, molecular Lande factors of the D[17.6] excited electronic state are unexpectedly sensitive to Ni isotope substitution at low J . These observations provide evidence for extensive mixing among electronic states, deviation from Hund’s case (a) coupling, and the existence of a local perturbing state. We also report polarization-dependent discrepancies between experimental and theoretical spectral intensities [1] for transitions involving the I[17.2] excited electronic state.