The rotational spectrum and derived structure of 1,2,3-triazine

Abstract

The close similarity in patterns of bands in the microwave spectra of the isomeric 1,2,3- and 1,2,4-triazines has enabled assignment for the 1,2,3-isomer. Pure rotational transitions with J up to 65 were identified and fitted to a Watson-type Hamiltonian: A = 6334.157(14)., B = 6271.289(14), C = 3151.230(14). A and B thus show near degeneracy. Coupled cluster calculations which include both singles, doubles and selected triple excitations (CCSD(T)), give very close agreement with the spectral data. The theoretical structure which includes estimates of the 14N quadrupole coupling, not determined in the spectrum, is described.