The Ground State Rotational Spectrum of Formaldehyde

Abstract The ground state rotational spectrum has been measured from 1 to 2600 GHz. These new measurements together with the older ones have been fitted to a standard A -reduced Watson-type Hamiltonian. The accuracy of the rotational and centrifugal distortion (including some octic ones) constants has been notably improved. The experimental constants are compared to the ab initio ones.