Abstract: | The microwave spectra of six isotopic species of selenoformaldehyde, H213C78,80Se, D2C78,80Se, and DHC78,80Se have been assigned. The resultant rotational constants, together with those of previous work yield the following substitution structure: r(C=Se) = 175.31 pm, HCH = 117.93°, and r(C---H) = 109.04 pm. This structure is compared with the equilibrium structure derived from ab initio calculations. The fundamental vibrational frequencies and centrifugal distortion constants of H2C80Se have been calculated. |