The pure rotational spectrum of thorium monosulfide, ThS

The separated field, pump/probe microwave optical double resonance technique was used to study the pure rotational transitions of Th³²S X¹Σ⁺. This is the first example of a microwave study of an actinide compound that is not an oxide. Eight rotational lines of ThS were observed, from which the rotational constants B = 3275.05033 ± 0.00041 and D = 0.0006699 ± 0.0000012 MHz were derived. Favorable comparisons with theoretical predictions support the assumption that computationally inexpensive density functional theory methods can provide reliable predictions for ground states of actinide-containing molecules.