Knowledge Bank

The microwave-optical double resonance technique has been used to observe rotational transitions in the $A~1A\prime \prime (000)$ state of both HNO and DNO. Twenty-nine and thirty-two rotational lines were observed in HNO and DNO, respectively, in the frequency region from rf to 90 GHz. They were analyzed to give effective rotational and centrifugal distortion constants. Perturbations were found in K-type doubling transitions for several subbands. Microwave transitions between levels in the $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A\prime \prime (000)$ state and `extra' levels were observed in HNO.