A determination of the molecular parameters of SeO in the X³Σ^- state

Abstract

The detection and measurement of Zeeman components of the J = 3 ←2 transitions in X³Σ^- SeO is reported. The experiments were of the fixed frequency/swept field type, performed at about 85 GHz. The EPR transitions in the J = 1, Ω = 1 level at 9 GHz have also been remeasured and combined with other millimetre-wave data (the J = 4 ←3 transition frequencies) and some optical data to determine the main molecular parameters for ⁷⁸SeO and ⁸⁰SeO in their ground states. These parameters are interpreted in terms of the admixture of excited electronic states by spin-orbit coupling (notably the b ¹Σ⁺ state), revealing the extent of case (c) coupling effects in the X³Σ^- state.