Submillimeter-wave spectroscopy of HN2+ and DN2+ in the excited vibrational states

The pure rotational transitions of HN2+ and DN2+ in the first excited vibrational states for all the fundamental vibrational modes have been observed in the range of 300-750 GHz. The molecular constants determined are much more accurate compared with those obtained from the infrared spectroscopy. The equilibrium rotational constants, Be = 46832.45 (71) MHz for HN2+ and Be = 38708.38 (58) MHz for DN2+, have been determined by correcting for the higher-order vibration-rotation interaction effects, γij, obtained by an infrared investigation. The equilibrium bond lengths are derived from these equilibrium rotational constants: re(H-N) = 1.03460 (14) Å and re (N-N) = 1.092698 (26) Å.