High resolution FIR spectra of DCNO and HCNO

With a new method it was possible to generate DCNO in amounts practical for high resolution spectroscopy. DCNO is spectroscopically the most interesti ng isotopically substituted species of the quasilinear molecule fulminic ac id, HCNO. Both DCNO and the parent isotopomer were reinvestigated in the fa r infrared region. The rovibrational spectra were recorded with a Bruker IF S 120 HR interferometer with resolutions (1/MOPD) between 0.0017 and 0.0028 cm(-1). The nu(5) fundamental and many hot bands of both isotopomers could be assigned. The spectral lines were weighted according to their signal-to -noise ratio for use in subsequent fitting procedures. Spectroscopic parame ters of an effective Hamiltonian for linear molecules were adjusted for the vibrational states (nu(1)nu(2)nu(3)nu(4)nu(5)) = (00000), (00001), (00002) , (00003), (00004) of DCNO and (nu(1)nu(2)nu(3)nu(4)nu(5)) = (00000), (0000 1), (00002), (00011), (00010), (00003) of HCNO. The search for the nu(4) fu ndamental of DCNO was not yet successful. The now well known Coriolis reson ance between the states (00002) and (00010) seen in HCNO does not effect th e spectrum of DCNO. However, a new resonance was observed in DCNO between t he levels with l = 0 and 2 of the (00001) state and the two pairs of levels with l = 1 of the (00012) state. (C) 2000 Elsevier Science B.V. All rights reserved.