The v₂=1 inversional dependence of the rotational g-tensors in ¹⁴NH₃, ¹⁵NH₃, and ¹⁵ND₃

Abstract

The ΔM_j =±1 mm-wave Zeeman spectra of the (v ₂, J, K)=(1⁺, 2, 1) ← (1⁻, 1, 1) ro-inversional transitions of ¹⁴NH₃ and ¹⁵NH₃, and of a series of (1⁻, J, K) → (1⁺, J, K) inversion transitions of ¹⁵ND₃, at fields near 2·6T, are reported. The level g-factors, referred to the nuclear magneton, are g(1⁺, 2, 1)=0·5771(20), g(1⁻, 1, 1)=0·5419(40) for ¹⁵NH₃ and 2g(1⁺, 2, 1) −g(1⁻, 1, 1)= 0·6119(30) for ¹⁴NH₃. The ¹⁵ND₃ field splittings obey standard rigid-rotor rules, leading to the g ⊥/1‡=0·2946(11) and g ‖/1‡=0·2523(6) excited-state g-tensor elements. The ¹⁵NH₃ ground-state g-tensor is redetermined to be g ⊥/0‡=0·5654(7), g ‖/0‡= 0·5024(5). The data is analysed in terms of the rotating rigid-bender model, fitted at three electronic parameters. Results show nuclear-electronic uncoupling with increasing v ₂, whereas increasing coupling is predicted for v ₂≧3, around the perpendicular axis. As a by-product, the K=3 splittings of the (4, 3) and (5, 3) inversion signals of ¹⁵ND₃ were resolved for the first time.