The experimental data was summarized by
(1) H. S. P. Müller, R. Gendriesch, L. Margulès, F. Lewen, G. Winnewisser, R. Bocquet, J. Demaison, U. Wötzel, and H. Mäder, 2000, Phys. Chem. Chem. Phys. 2, 3401.
At low temperatures, it may be necessary to discern between ortho-H₂¹³CO and para-H₂¹³CO. The ortho states are described by K_a odd, the para states by K_a even. The nuclear spin-weights are 3 and 1 for ortho-H₂¹³CO and para-H₂¹³CO, respectively. The J_KaKc = 1₁₁ is the lowest ortho state. It is 10.5135 cm^–1 above ground.
The dipole moment was measured by
(2) B. Fabricant, D. Krieger, and J. S. Muenter, 1977, J. Chem. Phys. 67, 1576.