Submillimeter microwave spectrum and spectroscopic constants of the OCS molecule: Isotopic species 16O12C33S and 18O12C32S

Abstract Microwave spectra of 16 O 12 C 33 S and 18 O 12 C 32 S in their natural isotopic abundances were investigated in the range 280–510 GHz. The effective rotational and centrifugal constants have been determined for all observed vibrational states. An analysis of the rotational spectrum taking account of l - and Fermi-resonances has been performed within each isotopic species.