Microwave optical double resonance spectrum of NH2. IV. Observation of an unusual rotational transition in ? 2<i>B</i>1

Abstract

Two rotational transitions in the ground 2B1 state of NH2—331, J=7/2←413, J=7/2 and 331, J =7/2←413, J=9/2—have been observed by microwave optical double resonance. The transitions are magnetic dipole allowed as a result of the spin–rotation interaction mixing of 413, J=7/2 with 331, J=7/2. An analysis of the mixing when combined with the previously determined spin–rotation centrifugal distortion parameters allows the determination of five of the six linearly independent spin–rotation centrifugal distortion constants. The resulting constants (in MHz) are ηaaaa=30.7(6), ηbbbb=0.624(14), ηaabb=−2.7(14), ηbbaa=−13.9(14), and (ηabab+ηabba)/2=3.4(2), where the quoted error in parentheses is three standard deviations.