HNCO
Isocyanic Acid
LAMDA | RADEX on-line

Because the JPL database includes hfs, we have recomputed the entire spectrum (without hfs) with the accurate constants of Niedenhoff et al. (1995, J. Mol. Spectrosc., 174, 151). For the lower transitions, these frequencies and transition probabilities agree with the weighted mean values tabulated in the JPL database well within the uncertainties. The same values of the dipole moments have been used as in the JPL tables, namely mu_a=1.602 and mu_b=1.350 Debye. The collision rates have been recomputed through use of S. Green's program for a larger number of levels than were included in his example. The recommended temperature range for these rates is 30-250 K. This data set could, in principle, be extended to higher states; however, owing to the large transition probabilities that connect states with K_a>3 to low-lying states, the populations of higher states are likely to be controlled by radiative processes and not collisions in most astrophysical environments of interest. At present no extrapolated rate coefficients are made available.

  • References
    Green, S. 1986, NASA Technical Memorandum 87791

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