Rotational analysis of the C˜2A1-X˜2A1 transition of SrNH2

The C˜2A1-X˜2A1 electronic transition of SrNH2 has been recorded at high resolution using laser-ablation/molecular jet techniques. Transitions arising from the Ka″=0 and Ka″=1 levels have been observed. The data have been analyzed using the S-reduced asymmetric top Hamiltonian to determine rotational and fine structure parameters. The spin-rotation constants of the C˜2A1 state were calculated using the pure precession model. These values were found to be in relatively good agreement with the experimentally determined parameters, however slight differences suggest that the unpaired electron in the C˜2A1 state is not entirely of p orbital character. A molecular structure was also determined for the C˜2A1 state of SrNH2. The strontium-nitrogen bond was found to decrease by 0.011 Å while the H-N-H bond angle was found to increase by 2.5° between the X˜2A1 and C˜2A1 states. A small positive inertial defect was calculated for the C˜2A1 state, indicating that the molecule is planar.