Vibration-rotation bands of trideuteromethyl iodide

The rotational fine structure of six parallel and nine perpendicular vibration bands of tri­deuteromethyl iodide has been analysed, and molecular constants have been derived. These include the band origins, the rotational constants in different vibrational levels, the αAi and αBi values, and the Coriolis coupling constants ςi for the fundamental degenerate vibrations. The ς values for overtone and combination bands have been compared with values calculated from the ςi values of the fundamentals, and agree closely with previous theoretical predictions.