Isocyanic Acid

Because the JPL database includes hfs, we have recomputed the entire spectrum (without hfs) with the accurate constants of Niedenhoff et al 1995. 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.

Collision data with ortho and para H2 are from Sahnoun et al 2018 and cover temperatures from 7 K to 300 K and states up to 145 cm-1 above ground.

Collision rates with He have been recomputed through use of S. Green's program for a larger number of levels than were included in his 1986 paper (NASA Technical Memorandum 87791). 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 Ka>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.

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