Investigation of a vibration-rotation interaction in DCO+ by millimeter wave spectroscopy

The rotational spectrum of DCO+ in the 0111, 0310 and 0400 vibrational excited states has been studied to derive the rotational, centrifugal distortion and l-type doubling constants. It has been found that there is a Coriolis-type interaction involving the 0111 and 1000 states, thus ruling out a previous hypothesis suggesting the existence of a Fermi resonance between the 1000 and 0400 states.