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

Abstract

Sub‐Doppler Zeeman spectra of the B ²Δ_5/2–X ²Δ_5/2(1–0) Q(2.5) line at 17 462.95 cm⁻¹, the A ²Δ_5/2–X ²Δ_5/2 (1–0) Q(2.5) line at 17 021.54 cm⁻¹, and the ²Φ_7/2–X ²Δ_5/2(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 ²Δ_5/2, X ²Δ_5/2, and ²Φ_7/2 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 ²Δ_5/2 is found to have a g value very different from that required for a ²Δ_5/2 state. Present experiments are unable to distinguish between the ⁴Φ_5/2 (g=2) and ⁴Π_5/2 (g=4) reassignment possibilities for the ab initio inexplicable A ²Δ_5/2 state.