The Zeeman effect as an aid to electronic assignment: The NiH <i>A</i> 2Δ5/2 state

Abstract

Sub-Doppler Zeeman spectra of the B 2Δ5/2–X 2Δ5/2(1–0) Q(2.5) line at 17 462.95 cm−1, the A 2Δ5/2–X 2Δ5/2 (1–0) Q(2.5) line at 17 021.54 cm−1, and the 2Φ7/2–X 2Δ5/2(0–0) R(2.5) line at 17 132.48 cm−1 were recorded at magnetic fields up to 900 G. The lowest-j levels of the B 2Δ5/2, X 2Δ5/2, and 2Φ7/2 states are found to behave as nearly pure Hund’s case (a)basis states with g values (Λ+2Σ) near g=3,3, and 4, respectively, but the A 2Δ5/2 is found to have a g value very different from that required for a 2Δ5/2 state. Present experiments are unable to distinguish between the 4Φ5/2 (g=2) and 4Π5/2 (g=4) reassignment possibilities for the ab initio inexplicable A 2Δ5/2 state.