Rotational analysis of the 0-0 band of the A3 ∏ inv-X3 ∑ − system of ND

The 0-0 band of the A³ ∏ _inv?X³ ∑ ^? system of ND was excited in an electrodeless microwave oscillator (2450 Mc./s.) discharge and photographed on a 6·6 meter concave grating spectrograph in the second order at a dispersion of 0·56 A/mm. Twenty-five out of the predicted twenty-seven branches have been identified in the rotational structure of the 0-0 band. From a rotational analysis, the following rotational constants have been determined: (i)X ³ ∑ ^? state—