New measurements of the microwave spectrum of formamide

New measurements of the microwave spectrum of formamide have been obtained in the frequency range from 49 to 340 GHz using the microwave spectrometer at the Institute of Radio Astronomy of NASU, Kharkov, Ukraine. An analysis of the rotational spectra of the ground, v₁₂, v₉, v₁₁ and 2v₁₂ excited vibrational states of the main isotopic species as well as of the ground states of the ¹³C, ¹⁵N and ¹⁸O substituted species has been carried out using SPFIT/SPCAT programs. The analysis of a strong Coriolis interaction coupling between v₉, v₁₁ and 2v₁₂ vibrational states of formamide has been also fulfilled as well as the analysis of the quadrupole hyperfine structure of the observed transitions. For the first time the quadrupole coupling parameters for the excited vibrational states and for the ¹⁸O substituted species of formamide were determined.