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

Abstract

We report molecular Landé factors for three Ω′=3/2 vibronic levels of NiH: E[17.8], D[17.6], and I[17.2], lying 17000–18000cm−1 above the ground electronic state. The molecular Landé factors of these three states exhibit unusual variations with J and with parity. Also, molecular Landé 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.