Zum Mikrowellenspektrum des Pyridazins

Abstract

The rotational spectrum of pyridazine in the vibrational ground state is reported for the parent species and three isotopically substituted species. The r s coordinates of the ring atoms have been reliably determined with the exception of the α coordinate of the Cl and the C4 atoms which is obviously too small for the application of KRAITCHMAN’S equations. The dipole moment was calculated from the STARK effect as μ α =4.22 D. The quadrupole coupling constants, from hfs measurements, are χ αα =— 4.64, χ bb =1.38, χ cc =3.27 MHz. The only non-diagonal quadrupole coupling tensor element has been less accurately determined from the variation of the hfs upon rotation of the principal axes system by isotopic substitution of one N 15 nucleus.