Fulminic acid is a quasi-linear molecule close to the linear limit. The lines were taken from
(1) B. P. Winnewisser, M. Winnewisser, G. Wagner, J. Preusser, 1990, J. Mol. Spectrosc. 142, 29.
The predictions should be reliable up to about 1200 GHz. Contributions of excited vibrational states to the partition function can be neglected up to about 50 K.
The dipole moment was assumed to agree with that of the main species, see e043509.cat.