Identification of triplet levels by Zeeman studies of microwave–optical double resonance in the system of thioformaldehyde

Microwave-optical double resonance experiments have been carried out in the presence of magnetic fields on the 410 band of the [Formula: see text] system of thioformaldehyde. Several anticrossings have been observed. The series of levels 60 6, 70 7, …. 120 12 of the 41 Ã1A2 state is shown to be perturbed by the 63 3, 73 4, …. 123 9 levels of the 21 31 ã3A2 state. Two anticrossings involving high vibronic levels of the ground state (X* levels) are explained by interactions with the 85 level of the 2142 ã3A2 state.