Knowledge Bank

We have observed some interesting microwave transitions in $NH2$ using microwave optical double resonance (MODR) with dye laser excited fluorescence detection. In the $X~2B1$ state, the transitions $331\leftarrow 413,J=7/2\leftarrow J=7/2$ and $J=7/2\leftarrow J=9/2$ at 5.3 GHz and 11.6 GHz, respectively have been observed. These transitions are allowed only because of the interaction between $331,J=7/2$ and $413,J=7/2$ through matrix elements of the spin rotation Hamiltonian both diagonal in K and off-diagonal by 2 in K, The adequacy of the Hamiltonian used to fit the centrifugal distortion effects in the spin rotation interaction will be discussed. Finally, the electric dipole allowed rovibronic transitions, (tentatively assigned as) $X~2B1(0,12,0),220\leftarrow A2A1\Pi (0,10,0)110,J=3/2\leftarrow J=3/2$ and $J=3/2\leftarrow 1/2$ at 15.7 GHz and 6.3 GHz, respectively, will be discussed. Several approaches to assigning these transitions and, consequently, to determining the energy level pattern for $220,J=3/2$, will be presented.