The lines were summarized in
(1) L. Nemes and M. Winnewisser, 1976, Z. Naturforsch. 31a, 272.
With respect to the Nov. 2003 entry, additional measurements between 229 and 341 GHz have been considered. They were published by
(2) A. Guarnieri, 2005, Z. Naturforsch. 60a, 619.
The line list was kindly provided by the author. Some higher order centrifugal distortion constants were kept fixed to values estimated from the main isotopomer, see e042501.cat. At low temperatures, it may be necessary to discern between ortho-D₂C₂O and para-D₂C₂O. The ortho states are described by K_a even, the para states by K_a odd. The nuclear spin-weights are 1 and 2 for ortho-D₂C₂O and para-D₂C₂O, respectively. The J_KaKc = 1₁₁ level is the lowest para level. It is 5.0048 cm^–1 above ground.
The dipole moment was assumed to be the same as for the main isotopomer, see e042501.cat.