The submillimeter-wave spectrum of hydrogenisocyanide, HNC, in its (0,0,0)and (0,1,0) vibrational states up to 2 THz

The submillimeter-wave spectrum of hydrogenisocyanide, HNC, in its ground v ibrational (0, 0, 0) and first excited bending states (0, 1, 0) (vibrationa l states are denoted (v(1), v(2), v(3))) has been measured from 453 to 1991 GHz spanning the rotational quantum numbers 5 less than or equal to J(u) l ess than or equal to 22. The new transition frequencies were fitted togethe r with previously published data, providing a comprehensive set of molecula r parameters up to sextic centrifugal distortion constants. The present dat a set allows for the prediction of accurate rest frequencies well beyond 2 THz.