Analysis of the 118.6 μm laser magnetic resonance spectra of PH, X3Σ− and a1Δ

Measurement and analysis of the 118.6 μm far infrared laser magnetic resonance spectra of the PH radical in its X3Σ− and a1Δ states are reported. The following rotational and fine structure parameters have been determined: X3Σ−: B0 = 8.412018 (27) cm−1, λ0 = 2.2067 (15) cm−1, γ0 = −0.076476 (48) cm−1; a1Δ: B0 = 8.4392925 (46) cm−1. The derived hyperfine constants are: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]; a1Δ: aH = 28 (15) MHz, aP = 768 (37) MHz. Within experimental error the hyperfine parameters yield identical values of [Formula: see text] for both electronic states.